My scientific work examines the study of species interactions in tropical ecosystems from California, Latin America, and other tropical areas of the world. Recent research highlights the decline of animal life (“defaunation”), and how this affects ecosystem processes/services (e.g. disease regulation). I teach ecology, natural history, conservation biology, and biocultural diversity at undergraduate and graduate levels at Stanford, and conduct science education programs with underserved children in the Bay Area and our study sites. My lab includes undergrads, graduate students, postdocs, and visiting scholars from the US, and many other countries. I have co-authored the new Framework for K-12 Science Education.

Academic Appointments

Administrative Appointments

  • Co-Director, INOGO Program of the Woods Institute for the Environment (2011 - Present)
  • Associate Chair for Diversity and Inclusion, School of Earth, Energy and Environment (2020 - Present)

Honors & Awards

  • Pew Scholar in Conservation, The Pew Charitable Trust (1992)
  • Outstanding Service Award: Teaching, Organization for Tropical Studies (2002)
  • Member, Mexican Academy of Sciences (2003)
  • Outstanding Researcher, Biology, National University of Mexico (2003)
  • Presidential Award in Ecology, Secretary of Environment, Mexico (2003)
  • Foreign Associate, US National Academy of Science (2004)
  • Foreign Member, American Academy of Arts and Sciences (2004)
  • Member, California Academy of Sciences (2008)
  • Medal of Honor (Science),, The State Congress, Morelos, Mexico (2015)
  • Merit in Ecology (Research), The Ecological Society of Mexico (2015)
  • Miriam Arnold Rollan Prize for Community Service, Stanford University (2016)
  • Medal Alfonso L. Herrera: Distinguished Scientist, Universidad Autonoma de Puebla, Mexico (2017)
  • Medal for Merit in Research and Education, International Association for Tropical Biology (ATBC) (2017)
  • President Miguel Aleman Medal for outstanding work in ecology and environmental problems, Mexico City (2017)
  • Medal Luis Cifuentes, Mexican Federation of Biologists, Area of Research Puerto Vallarta, Mexico (2020)

Boards, Advisory Committees, Professional Organizations

  • Board Member, Turning Green (2021 - Present)
  • Board Member, Stop Extinction (2020 - Present)
  • Group member, Zoonotic Diseases Working Group of International Union of Biological Sciences (2020 - Present)
  • Committee member, Stanford Biology Diversity Equity and Inclusion (2020 - Present)
  • Committee member, Stanford Public Art Committee (2019 - Present)
  • Board Member, Stanford Breadth Governance Board (2019 - Present)
  • Board Member, Biological Sciences Curriculum Studies (2019 - Present)
  • Advisory Board, Stanford Bing Over Seas Program (2013 - Present)
  • Advisory Committee, Jasper Ridge Biological Preserve (2008 - Present)

Program Affiliations

  • Center for Latin American Studies

Professional Education

  • B.Sc., University of Morelos, Mexico, Biology (1972)
  • M.Sc., University of Wales, Ecology (1977)
  • Ph.D., University of Wales, Ecology (1980)

Community and International Work

  • Plant-animal interactions, Mexico, Costa Rica, Amazonia


    ecology and evolutionary biology

    Partnering Organization(s)

    National University of Mexico, Organization for Tropical Studies, Amazonian Institute of Research

    Populations Served

    USA and LAtin American Students and policy makers



    Ongoing Project


    Opportunities for Student Involvement


Current Research and Scholarly Interests

My interests are centered on the study of species interactions, trying to understand how the ecology and evolution of plants is affected by other living organisms, particularly animals (herbivores, pollinators, seed dispersal agents, and seed predators) and pathogens. My work is focused on tropical forest ecosystems, particulalry in Latin America, particularly Mexico, Costa Rica and Amazonia, but I am also conducting similar studies in other ecosystems as well. More recently, I have been conducting research in East Africa (Kenya, Tanzania), looking at how anthropogenic impact affects ecological interactions between plants and animals.
In the field of conservation biology, I am interested in studying the consequences of anthropogenic impact on the disruption of ecological processes and ecosystem services, including the importance of species interactions in human disease regulation.
Finally, I have a major interest in environmental education and sharing of my experiences in ecology and conservation, with the general public and students of all levels.


  • Effect of Herbivores on Plant Diversity, National University of Mexico (UNAM)

    This project examines via experimental manipulations and observations, the impact of herbivores on plant community, structure and diversity.



  • Effects of natural enemies (herbivorous animals and fungi) on the ecology of plants in tropical forest ecosystems, Stanford University, in collaboration with UNAM (Mexico), and other Brazilian institutions

    We seek to understand how the plants' natural enemies affect the ecology and evolutionary trajectories of plants in tropical ecosystems in Latin America.


    Mexico, Costa Rica, Panama, Brazil.

  • Anthropogenic impact on species interactions in tropical and temperate ecosystems, Stanford University

    This is a multi-faceted project aimed at understanding how drivers of global environmental change (deforestation, animal over-exploitation [defaunation], invasive species, and the interaction among drivers of global change affect the ecological interactions between species and how this, in turn, threatens ecosystem services.


    Mexico, Brazil, Kenya, the Channel Islands (Central Pacific)


    • Hillary Young, Professor, University of California Santa Barbara
  • Effects of biological enrichment on biodiversity and disease risk in oil palm plantations, Stanford University (Woods Institute)

    We are experimentally testing the effects of diversification (plant species enrichment) on the control of disease and productivity of oil palms, as well as on zoonotic disease risks in humans, as part of a larger project (INOGO) that attempts to combine biodiversity conservation with human wellbeing.


    OSa Peninsula and Golfito Canton in Costa Rica


    • Willliam Durham, Professor, Stanford University
  • Effects of defamation on ecosystem processes and services

    This research examines how the local loss of animal populations affects ecosystem processes generating a cascade of ecological consequences including degradation or loss of ecosystem services such as disease regulation


    Mexico, Kenya, Costa Rica


    • Michael Scmidt, Senior Researcher, Mexico's NAtional Commission for Biodiversity

2020-21 Courses

Stanford Advisees

Graduate and Fellowship Programs

  • Biology (School of Humanities and Sciences) (Phd Program)

All Publications

  • Incidence of Galls on Sympatric California Oaks: Ecological and Physiological Perspectives DIVERSITY-BASEL Perea, R., Dirzo, R., Bieler, S., Wilson Fernandes, G. 2021; 13 (1)

    View details for DOI 10.3390/d13010020

    View details for Web of Science ID 000610134000001

  • Host plant phylogeny and abundance predict root-associated fungal community composition and diversity of mutualists and pathogens JOURNAL OF ECOLOGY Schroeder, J. W., Martin, J. T., Angulo, D. F., Arias-Del Razo, I., Barbosa, J. M., Perea, R., Sebastian-Gonzalez, E., Dirzo, R. 2019; 107 (4): 1557–66
  • Nurse plant size and biotic stress determine quantity and quality of plant facilitation in oak savannas FOREST ECOLOGY AND MANAGEMENT Pelaez, M., Dirzo, R., Fernandes, G., Perea, R. 2019; 437: 435–42
  • An island of wildlife in a human-dominated landscape: The last fragment of primary forest on the Osa Peninsula's Golfo Dulce coastline, Costa Rica PLOS ONE Gutierrez, B., Zambrano, A., Zambrano, S., Gil, C., Bohlman, S., Avellan Arias, E., Mulder, G., Ols, C., Dirzo, R., DeLuycker, A. M., Lewis, K., Broadbent, E. N. 2019; 14 (3)
  • Rodent community responses to vegetation and landscape changes in early successional stages of tropical dry forest FOREST ECOLOGY AND MANAGEMENT Patricia Morales-Diaz, S., Yolotl Alvarez-Anorve, M., Edith Zamora-Espinoza, M., Dirzo, R., Oyama, K., Daniel Avila-Cabadilla, L. 2019; 433: 633–44
  • An island of wildlife in a human-dominated landscape: The last fragment of primary forest on the Osa Peninsula's Golfo Dulce coastline, Costa Rica. PloS one Gutierrez, B. L., Almeyda Zambrano, A. M., Almeyda Zambrano, S. L., Quispe Gil, C. A., Bohlman, S., Avellan Arias, E., Mulder, G., Ols, C., Dirzo, R., DeLuycker, A. M., Lewis, K., Broadbent, E. N. 2019; 14 (3): e0214390


    Habitat loss and fragmentation, together with related edge effects, are the primary cause of global biodiversity decline. Despite a large amount of research quantifying and demonstrating the degree of these effects, particularly in top predators and their prey, most fragmented patches are lost before their conservation value is recognized. This study evaluates terrestrial vertebrates in Playa Sandalo, in the Osa Peninsula of Costa Rica, which represents the last patch of "primary" forest in the most developed part of this region. Our study indicates that the diversity of ground species detected within Playa Sandalo rival other areas under active conservation like Lapa Rios Ecolodge. Historical fragmentation, together with the maintenance of forest cover in isolated conditions, are potentially responsible for the species composition observed within Playa Sandalo; facilitating the development of a prey-predator system including ocelots, medium-size mammals, and birds at the top of the trophic chain. The high diversity of both habitat and vertebrates, its prime location and cultural value, as well as its unique marine importance represent the ideal conditions for conservation. Conservation of Playa Sandalo, and other small tropical forest remnants, might represent the only management option for wildlife conservation within ever growing human-dominated landscapes.

    View details for PubMedID 30913255

  • Nature Divided, Scientists United: US-Mexico Border Wall Threatens Biodiversity and Binational Conservation BIOSCIENCE Peters, R., Ripple, W. J., Wolf, C., Moskwik, M., Carreon-Arroyo, G., Ceballos, G., Cordova, A., Dirzo, R., Ehrlich, P. R., Flesch, A. D., List, R., Lovejoy, T. E., Noss, R. F., Pacheco, J., Sarukhan, J. K., Soule, M. E., Wilson, E. O., Miller, J. B. 2018; 68 (10): 740–43
  • Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Ceballos, G., Ehrlich, P. R., Dirzo, R. 2017; 114 (30): E6089–E6096


    The population extinction pulse we describe here shows, from a quantitative viewpoint, that Earth's sixth mass extinction is more severe than perceived when looking exclusively at species extinctions. Therefore, humanity needs to address anthropogenic population extirpation and decimation immediately. That conclusion is based on analyses of the numbers and degrees of range contraction (indicative of population shrinkage and/or population extinctions according to the International Union for Conservation of Nature) using a sample of 27,600 vertebrate species, and on a more detailed analysis documenting the population extinctions between 1900 and 2015 in 177 mammal species. We find that the rate of population loss in terrestrial vertebrates is extremely high-even in "species of low concern." In our sample, comprising nearly half of known vertebrate species, 32% (8,851/27,600) are decreasing; that is, they have decreased in population size and range. In the 177 mammals for which we have detailed data, all have lost 30% or more of their geographic ranges and more than 40% of the species have experienced severe population declines (>80% range shrinkage). Our data indicate that beyond global species extinctions Earth is experiencing a huge episode of population declines and extirpations, which will have negative cascading consequences on ecosystem functioning and services vital to sustaining civilization. We describe this as a "biological annihilation" to highlight the current magnitude of Earth's ongoing sixth major extinction event.

    View details for PubMedID 28696295

  • Species traits and interaction rules shape a species-rich seed-dispersal interaction network. Ecology and evolution Sebastián-González, E. n., Pires, M. M., Donatti, C. I., Guimarães, P. R., Dirzo, R. n. 2017; 7 (12): 4496–4506


    Species phenotypic traits affect the interaction patterns and the organization of seed-dispersal interaction networks. Understanding the relationship between species characteristics and network structure help us understand the assembly of natural communities and how communities function. Here, we examine how species traits may affect the rules leading to patterns of interaction among plants and fruit-eating vertebrates. We study a species-rich seed-dispersal system using a model selection approach to examine whether the rules underlying network structure are driven by constraints in fruit resource exploitation, by preferential consumption of fruits by the frugivores, or by a combination of both. We performed analyses for the whole system and for bird and mammal assemblages separately, and identified the animal and plant characteristics shaping interaction rules. The structure of the analyzed interaction network was better explained by constraints in resource exploitation in the case of birds and by preferential consumption of fruits with specific traits for mammals. These contrasting results when looking at bird-plant and mammal-plant interactions suggest that the same type of interaction is organized by different processes depending on the assemblage we focus on. Size-related restrictions of the interacting species (both for mammals and birds) were the most important factors driving the interaction rules. Our results suggest that the structure of seed-dispersal interaction networks can be explained using species traits and interaction rules related to simple ecological mechanisms.

    View details for PubMedID 28649359

    View details for PubMedCentralID PMC5478084

  • Patterns of orchid bee species diversity and turnover among forested plateaus of central Amazonia. PloS one Antonini, Y. n., Machado, C. d., Galetti, P. M., Oliveira, M. n., Dirzo, R. n., Fernandes, G. W. 2017; 12 (4): e0175884


    The knowledge of spatial pattern and geographic beta-diversity is of great importance for biodiversity conservation and interpreting ecological information. Tropical forests, especially the Amazon Rainforest, are well known for their high species richness and low similarity in species composition between sites, both at local and regional scales. We aimed to determine the effect and relative importance of area, isolation and climate on species richness and turnover in orchid bee assemblages among plateaus in central Brazilian Amazonia. Variance partitioning techniques were applied to assess the relative effects of spatial and environmental variables on bee species richness, phylogeny and composition. We hypothesized that greater abundance and richness of orchid bees would be found on larger plateaus, with a set of core species occurring on all of them. We also hypothesized that smaller plateaus would possess lower phylogenetic diversity. We found 55 bee species distributed along the nine sampling sites (plateaus) with 17 of them being singletons. There was a significant decrease in species richness with decreasing size of plateaus, and a significant decrease in the similarity in species composition with greater distance and climatic variation among sampling sites. Phylogenetic diversity varied among the sampling sites but was directly related to species richness. Although not significantly related to plateau area, smaller or larger PDFaith were observed in the smallest and the largest plateaus, respectively.

    View details for PubMedID 28410432

    View details for PubMedCentralID PMC5391963

  • Scattered trees and livestock grazing as keystones organisms for sustainable use and conservation of Mediterranean dehesas JOURNAL FOR NATURE CONSERVATION Lopez-Sanchez, A., Miguel, A. S., Dirzo, R., Roig, S. 2016; 33: 58-67
  • Anthropogenic disturbances jeopardize biodiversity conservation within tropical rainforest reserves PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Martinez-Ramos, M., Ortiz-Rodriguez, I. A., Pinero, D., Dirzo, R., Sarukhan, J. 2016; 113 (19): 5323-5328


    Anthropogenic disturbances affecting tropical forest reserves have been documented, but their ecological long-term cumulative effects are poorly understood. Habitat fragmentation and defaunation are two major anthropogenic threats to the integrity of tropical reserves. Based on a long-term (four decades) study, we document how these disturbances synergistically disrupt ecological processes and imperil biodiversity conservation and ecosystem functioning at Los Tuxtlas, the northernmost tropical rainforest reserve in the Americas. Deforestation around this reserve has reduced the reserve to a medium-sized fragment (640 ha), leading to an increased frequency of canopy-gap formation. In addition, hunting and habitat loss have caused the decline or local extinction of medium and large herbivores. Combining empirical, experimental, and modeling approaches, we support the hypothesis that such disturbances produced a demographic explosion of the long-lived (≈120 y old, maximum height of 7 m) understory palm Astrocaryum mexicanum, whose population has increased from 1,243-4,058 adult individuals per hectare in only 39 y (annual growth rate of ca 3%). Faster gap formation increased understory light availability, enhancing seed production and the growth of immature palms, whereas release from mammalian herbivory and trampling increased survival of seedlings and juveniles. In turn, the palm's demographic explosion was followed by a reduction of tree species diversity, changing forest composition, altering the relative contribution of trees to forest biomass, and disrupting litterfall dynamics. We highlight how indirect anthropogenic disturbances (e.g., palm proliferation) on otherwise protected areas threaten tropical conservation, a phenomenon that is currently eroding the planet's richest repositories of biodiversity.

    View details for DOI 10.1073/pnas.1602893113

    View details for Web of Science ID 000375478800062

    View details for PubMedID 27071122

    View details for PubMedCentralID PMC4868451

  • Large wildlife removal drives immune defence increases in rodents FUNCTIONAL ECOLOGY Young, H. S., Dirzo, R., Helgen, K. M., McCauley, D. J., Nunn, C. L., Snyder, P., Veblen, K. E., Zhao, S., Ezenwa, V. O. 2016; 30 (5): 799-807
  • Livestock vs. wild ungulate management in the conservation of Mediterranean dehesas: Implications for oak regeneration FOREST ECOLOGY AND MANAGEMENT Lopez-Sanchez, A., Perea, R., Dirzo, R., Roig, S. 2016; 362: 99-106
  • Hemiparasite-host plant interactions in a fragmented landscape assessed via imaging spectroscopy and LiDAR ECOLOGICAL APPLICATIONS Barbosa, J. M., Sebastian-Gonzalez, E., Asner, G. P., Knapp, D. E., Anderson, C., Martin, R. E., Dirzo, R. 2016; 26 (1): 55-66

    View details for DOI 10.1890/14.2429

    View details for Web of Science ID 000369511000006

  • Saving the World's Terrestrial Megafauna. Bioscience Ripple, W. J., Chapron, G. n., López-Bao, J. V., Durant, S. M., Macdonald, D. W., Lindsey, P. A., Bennett, E. L., Beschta, R. L., Bruskotter, J. T., Campos-Arceiz, A. n., Corlett, R. T., Darimont, C. T., Dickman, A. J., Dirzo, R. n., Dublin, H. T., Estes, J. A., Everatt, K. T., Galetti, M. n., Goswami, V. R., Hayward, M. W., Hedges, S. n., Hoffmann, M. n., Hunter, L. T., Kerley, G. I., Letnic, M. n., Levi, T. n., Maisels, F. n., Morrison, J. C., Nelson, M. P., Newsome, T. M., Painter, L. n., Pringle, R. M., Sandom, C. J., Terborgh, J. n., Treves, A. n., Van Valkenburgh, B. n., Vucetich, J. A., Wirsing, A. J., Wallach, A. D., Wolf, C. n., Woodroffe, R. n., Young, H. n., Zhang, L. n. 2016; 66 (10): 807–12

    View details for PubMedID 28533560

  • Tropical Forest Fragmentation Affects Floral Visitors but Not the Structure of Individual-Based Palm-Pollinator Networks PLOS ONE Dattilo, W., Aguirre, A., Quesada, M., Dirzo, R. 2015; 10 (3)


    Despite increasing knowledge about the effects of habitat loss on pollinators in natural landscapes, information is very limited regarding the underlying mechanisms of forest fragmentation affecting plant-pollinator interactions in such landscapes. Here, we used a network approach to describe the effects of forest fragmentation on the patterns of interactions involving the understory dominant palm Astrocaryum mexicanum (Arecaceae) and its floral visitors (including both effective and non-effective pollinators) at the individual level in a Mexican tropical rainforest landscape. Specifically, we asked: (i) Does fragment size affect the structure of individual-based plant-pollinator networks? (ii) Does the core of highly interacting visitor species change along the fragmentation size gradient? (iii) Does forest fragment size influence the abundance of effective pollinators of A. mexicanum? We found that fragment size did not affect the topological structure of the individual-based palm-pollinator network. Furthermore, while the composition of peripheral non-effective pollinators changed depending on fragment size, effective core generalist species of pollinators remained stable. We also observed that both abundance and variance of effective pollinators of male and female flowers of A. mexicanum increased with forest fragment size. These findings indicate that the presence of effective pollinators in the core of all forest fragments could keep the network structure stable along the gradient of forest fragmentation. In addition, pollination of A. mexicanum could be more effective in larger fragments, since the greater abundance of pollinators in these fragments may increase the amount of pollen and diversity of pollen donors between flowers of individual plants. Given the prevalence of fragmentation in tropical ecosystems, our results indicate that the current patterns of land use will have consequences on the underlying mechanisms of pollination in remnant forests.

    View details for DOI 10.1371/journal.pone.0121275

    View details for Web of Science ID 000352084800039

    View details for PubMedID 25826702

    View details for PubMedCentralID PMC4380365

  • Context-dependent effects of large-wildlife declines on small-mammal communities in central Kenya ECOLOGICAL APPLICATIONS Young, H. S., McCauley, D. J., Dirzo, R., Goheen, J. R., Agwanda, B., Brook, C., Otarola-Castillo, E., Ferguson, A. W., Kinyua, S. N., McDonough, M. M., Palmer, T. M., Pringle, R. M., Young, T. P., Helgen, K. M. 2015; 25 (2): 348-360

    View details for DOI 10.1890/14-0995.1

    View details for Web of Science ID 000350556400004

  • Strategic Actions to Value, Conserve, and Restore the Natural Capital of Megadiversity Countries: The Case of Mexico. Bioscience Sarukhán, J. n., Urquiza-Haas, T. n., Koleff, P. n., Carabias, J. n., Dirzo, R. n., Ezcurra, E. n., Cerdeira-Estrada, S. n., Soberón, J. n. 2015; 65 (2): 164–73


    Decisionmakers need updated, scientifically sound and relevant information to implement appropriate policy measures and make innovative commitments to halt biodiversity loss and improve human well-being. Here, we present a recent science-based synthesis on the biodiversity and ecosystem services of Mexico, intended to be a tool for policymakers. We describe the methodological approach used to undertake such an assessment and highlight the major findings. Organized into five volumes and originally written in Spanish (Capital Natural de México), it summarizes the available knowledge on the components, structure, and functioning of the biodiversity of Mexico; the threats and trajectories of anthropogenic impact, together with its conservation status; and the policies, institutions, and instruments available for its sustainable management. We stress the lessons learned that can be useful for similar exercises in other megadiverse developing countries and identify major gaps and strategic actions to conserve the natural capital in light of the challenges of the Anthropocene.

    View details for PubMedID 26955077

    View details for PubMedCentralID PMC4778169

  • Habitat Heterogeneity Affects Plant and Arthropod Species Diversity and Turnover in Traditional Cornfields. PloS one Martínez, E. n., Rös, M. n., Bonilla, M. A., Dirzo, R. n. 2015; 10 (7): e0128950


    The expansion of the agricultural frontier by the clearing of remnant forests has led to human-dominated landscape mosaics. Previous studies have evaluated the effect of these landscape mosaics on arthropod diversity at local spatial scales in temperate and tropical regions, but little is known about fragmentation effects in crop systems, such as the complex tropical traditional crop systems that maintain a high diversity of weeds and arthropods in low-Andean regions. To understand the factors that influence patterns of diversity in human-dominated landscapes, we investigate the effect of land use types on plant and arthropod diversity in traditionally managed cornfields, via surveys of plants and arthropods in twelve traditional cornfields in the Colombian Andes. We estimated alpha and beta diversity to analyze changes in diversity related to land uses within a radius of 100 m to 1 km around each cornfield. We observed that forests influenced alpha diversity of plants, but not of arthropods. Agricultural lands had a positive relationship with plants and herbivores, but a negative relationship with predators. Pastures positively influenced the diversity of plants and arthropods. In addition, forest cover seemed to influence changes in plant species composition and species turnover of herbivore communities among cornfields. The dominant plant species varied among fields, resulting in high differentiation of plant communities. Predator communities also exhibited high turnover among cornfields, but differences in composition arose mainly among rare species. The crop system evaluated in this study represents a widespread situation in the tropics, therefore, our results can be of broad significance. Our findings suggest that traditional agriculture may not homogenize biological communities, but instead could maintain the regional pool of species through high beta diversity.

    View details for PubMedID 26197473

    View details for PubMedCentralID PMC4510542

  • Long-term vegetation changes in a temperate forest impacted by climate change ECOSPHERE Oakes, L. E., Hennon, P. E., O'Hara, K. L., Dirzo, R. 2014; 5 (10)
  • Differentiating genetic and environmental drivers of plant-pathogen community interactions JOURNAL OF ECOLOGY Busby, P. E., Newcombe, G., Dirzo, R., Whitham, T. G. 2014; 102 (5): 1300-1309
  • Reconstructing past ecological networks: the reconfiguration of seed-dispersal interactions after megafaunal extinction. Oecologia Pires, M. M., Galetti, M., Donatti, C. I., Pizo, M. A., Dirzo, R., Guimarães, P. R. 2014; 175 (4): 1247-1256


    The late Quaternary megafaunal extinction impacted ecological communities worldwide, and affected key ecological processes such as seed dispersal. The traits of several species of large-seeded plants are thought to have evolved in response to interactions with extinct megafauna, but how these extinctions affected the organization of interactions in seed-dispersal systems is poorly understood. Here, we combined ecological and paleontological data and network analyses to investigate how the structure of a species-rich seed-dispersal network could have changed from the Pleistocene to the present and examine the possible consequences of such changes. Our results indicate that the seed-dispersal network was organized into modules across the different time periods but has been reconfigured in different ways over time. The episode of megafaunal extinction and the arrival of humans changed how seed dispersers were distributed among network modules. However, the recent introduction of livestock into the seed-dispersal system partially restored the original network organization by strengthening the modular configuration. Moreover, after megafaunal extinctions, introduced species and some smaller native mammals became key components for the structure of the seed-dispersal network. We hypothesize that such changes in network structure affected both animal and plant assemblages, potentially contributing to the shaping of modern ecological communities. The ongoing extinction of key large vertebrates will lead to a variety of context-dependent rearranged ecological networks, most certainly affecting ecological and evolutionary processes.

    View details for DOI 10.1007/s00442-014-2971-1

    View details for PubMedID 24865393

  • Defaunation in the Anthropocene SCIENCE Dirzo, R., Young, H. S., Galetti, M., Ceballos, G., Isaac, N. J., Collen, B. 2014; 345 (6195): 401-406


    We live amid a global wave of anthropogenically driven biodiversity loss: species and population extirpations and, critically, declines in local species abundance. Particularly, human impacts on animal biodiversity are an under-recognized form of global environmental change. Among terrestrial vertebrates, 322 species have become extinct since 1500, and populations of the remaining species show 25% average decline in abundance. Invertebrate patterns are equally dire: 67% of monitored populations show 45% mean abundance decline. Such animal declines will cascade onto ecosystem functioning and human well-being. Much remains unknown about this "Anthropocene defaunation"; these knowledge gaps hinder our capacity to predict and limit defaunation impacts. Clearly, however, defaunation is both a pervasive component of the planet's sixth mass extinction and also a major driver of global ecological change.

    View details for DOI 10.1126/science.1251817

    View details for Web of Science ID 000339655100031

    View details for PubMedID 25061202

  • Declines in large wildlife increase landscape-level prevalence of rodent-borne disease in Africa PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Young, H. S., Dirzo, R., Helgen, K. M., McCauley, D. J., Billeter, S. A., Kosoy, M. Y., Osikowicz, L. M., Salkeld, D. J., Young, T. P., Dittmar, K. 2014; 111 (19): 7036-7041


    Populations of large wildlife are declining on local and global scales. The impacts of this pulse of size-selective defaunation include cascading changes to smaller animals, particularly rodents, and alteration of many ecosystem processes and services, potentially involving changes to prevalence and transmission of zoonotic disease. Understanding linkages between biodiversity loss and zoonotic disease is important for both public health and nature conservation programs, and has been a source of much recent scientific debate. In the case of rodent-borne zoonoses, there is strong conceptual support, but limited empirical evidence, for the hypothesis that defaunation, the loss of large wildlife, increases zoonotic disease risk by directly or indirectly releasing controls on rodent density. We tested this hypothesis by experimentally excluding large wildlife from a savanna ecosystem in East Africa, and examining changes in prevalence and abundance of Bartonella spp. infection in rodents and their flea vectors. We found no effect of wildlife removal on per capita prevalence of Bartonella infection in either rodents or fleas. However, because rodent and, consequently, flea abundance doubled following experimental defaunation, the density of infected hosts and infected fleas was roughly twofold higher in sites where large wildlife was absent. Thus, defaunation represents an elevated risk in Bartonella transmission to humans (bartonellosis). Our results (i) provide experimental evidence of large wildlife defaunation increasing landscape-level disease prevalence, (ii) highlight the importance of susceptible host regulation pathways and host/vector density responses in biodiversity-disease relationships, and (iii) suggest that rodent-borne disease responses to large wildlife loss may represent an important context where this relationship is largely negative.

    View details for DOI 10.1073/pnas.1404958111

    View details for Web of Science ID 000335798000068

    View details for PubMedID 24778215

    View details for PubMedCentralID PMC4024866

  • Differential plant damage due to litterfall in palm-dominated forest stands in a Central Pacific atoll JOURNAL OF TROPICAL ECOLOGY Young, H. S., McCauley, D. J., Pollock, A., Dirzo, R. 2014; 30: 231-236
  • Integrating stand and soil properties to understand foliar nutrient dynamics during forest succession following slash-and-burn agriculture in the Bolivian Amazon. PloS one Broadbent, E. N., Almeyda Zambrano, A. M., Asner, G. P., Soriano, M., Field, C. B., de Souza, H. R., Peña-Claros, M., Adams, R. I., Dirzo, R., Giles, L. 2014; 9 (2)


    Secondary forests cover large areas of the tropics and play an important role in the global carbon cycle. During secondary forest succession, simultaneous changes occur among stand structural attributes, soil properties, and species composition. Most studies classify tree species into categories based on their regeneration requirements. We use a high-resolution secondary forest chronosequence to assign trees to a continuous gradient in species successional status assigned according to their distribution across the chronosequence. Species successional status, not stand age or differences in stand structure or soil properties, was found to be the best predictor of leaf trait variation. Foliar δ(13)C had a significant positive relationship with species successional status, indicating changes in foliar physiology related to growth and competitive strategy, but was not correlated with stand age, whereas soil δ(13)C dynamics were largely constrained by plant species composition. Foliar δ(15)N had a significant negative correlation with both stand age and species successional status, - most likely resulting from a large initial biomass-burning enrichment in soil (15)N and (13)C and not closure of the nitrogen cycle. Foliar %C was neither correlated with stand age nor species successional status but was found to display significant phylogenetic signal. Results from this study are relevant to understanding the dynamics of tree species growth and competition during forest succession and highlight possibilities of, and potentially confounding signals affecting, the utility of leaf traits to understand community and species dynamics during secondary forest succession.

    View details for DOI 10.1371/journal.pone.0086042

    View details for PubMedID 24516525

    View details for PubMedCentralID PMC3917844

  • Water stress strengthens mutualism among ants, trees, and scale insects. PLoS biology Pringle, E. G., Akçay, E., Raab, T. K., Dirzo, R., Gordon, D. M. 2013; 11 (11)


    Abiotic environmental variables strongly affect the outcomes of species interactions. For example, mutualistic interactions between species are often stronger when resources are limited. The effect might be indirect: water stress on plants can lead to carbon stress, which could alter carbon-mediated plant mutualisms. In mutualistic ant-plant symbioses, plants host ant colonies that defend them against herbivores. Here we show that the partners' investments in a widespread ant-plant symbiosis increase with water stress across 26 sites along a Mesoamerican precipitation gradient. At lower precipitation levels, Cordia alliodora trees invest more carbon in Azteca ants via phloem-feeding scale insects that provide the ants with sugars, and the ants provide better defense of the carbon-producing leaves. Under water stress, the trees have smaller carbon pools. A model of the carbon trade-offs for the mutualistic partners shows that the observed strategies can arise from the carbon costs of rare but extreme events of herbivory in the rainy season. Thus, water limitation, together with the risk of herbivory, increases the strength of a carbon-based mutualism.

    View details for DOI 10.1371/journal.pbio.1001705

    View details for PubMedID 24223521

    View details for PubMedCentralID PMC3818173

  • Richness and Abundance of Ichneumonidae in a Fragmented Tropical Rain Forest NEOTROPICAL ENTOMOLOGY Ruiz-Guerra, B., Hanson, P., Guevara, R., Dirzo, R. 2013; 42 (5): 458-465
  • Consumer preference for seeds and seedlings of rare species impacts tree diversity at multiple scales OECOLOGIA Young, H. S., McCauley, D. J., Guevara, R., Dirzo, R. 2013; 172 (3): 857-867


    Positive density-dependent seed and seedling predation, where herbivores selectively eat seeds or seedlings of common species, is thought to play a major role in creating and maintaining plant community diversity. However, many herbivores and seed predators are known to exhibit preferences for rare foods, which could lead to negative density-dependent predation. In this study, we first demonstrate the occurrence of increased predation of locally rare tree species by a widespread group of insular seed and seedling predators, land crabs. We then build computer simulations based on these empirical data to examine the effects of such predation on diversity patterns. Simulations show that herbivore preferences for locally rare species are likely to drive scale-dependent effects on plant community diversity: at small scales these foraging patterns decrease plant community diversity via the selective consumption of rare plant species, while at the landscape level they should increase diversity, at least for short periods, by promoting clustered local dominance of a variety of species. Finally, we compared observed patterns of plant diversity at the site to those obtained via computer simulations, and found that diversity patterns generated under simulations were highly consistent with observed diversity patterns. We posit that preference for rare species by herbivores may be prevalent in low- or moderate-diversity systems, and that these effects may help explain diversity patterns across different spatial scales in such ecosystems.

    View details for DOI 10.1007/s00442-012-2542-2

    View details for Web of Science ID 000320409100021

    View details for PubMedID 23229391

  • Effects of mammalian herbivore declines on plant communities: observations and experiments in an African savanna JOURNAL OF ECOLOGY Young, H. S., McCauley, D. J., Helgen, K. M., Goheen, J. R., Otarola-Castillo, E., Palmer, T. M., Pringle, R. M., Young, T. P., Dirzo, R. 2013; 101 (4): 1030-1041
  • Genetic basis of pathogen community structure for foundation tree species in a common garden and in the wild JOURNAL OF ECOLOGY Busby, P. E., Newcombe, G., Dirzo, R., Whitham, T. G. 2013; 101 (4): 867-877
  • Ecological and evolutionary consequences of living in a defaunated world BIOLOGICAL CONSERVATION Galetti, M., Dirzo, R. 2013; 163: 1-6
  • Effects of grasses on sapling establishment and the role of transplanted saplings on the light environment of pastures: implications for tropical forest restoration APPLIED VEGETATION SCIENCE Meli, P., Dirzo, R. 2013; 16 (2): 296-304
  • The roles of productivity and ecosystem size in determining food chain length in tropical terrestrial ecosystems ECOLOGY Young, H. S., McCauley, D. J., Dunbar, R. B., Hutson, M. S., Ter-Kuile, M., Dirzo, R. 2013; 94 (3): 692-701


    Many different drivers, including productivity, ecosystem size, and disturbance, have been considered to explain natural variation in the length of food chains. Much remains unknown about the role of these various drivers in determining food chain length, and particularly about the mechanisms by which they may operate in terrestrial ecosystems, which have quite different ecological constraints than aquatic environments, where most food chain length studies have been thus far conducted. In this study, we tested the relative importance of ecosystem size and productivity in influencing food chain length in a terrestrial setting. We determined that (1) there is no effect of ecosystem size or productive space on food chain length; (2) rather, food chain length increases strongly and linearly with productivity; and (3) the observed changes in food chain length are likely achieved through a combination of changes in predator size, predator behavior, and consumer diversity along gradients in productivity. These results lend new insight into the mechanisms by which productivity can drive changes in food chain length, point to potential for systematic differences in the drivers of food web structure between terrestrial and aquatic systems, and challenge us to consider how ecological context may control the drivers that shape food chain length.

    View details for Web of Science ID 000317044300016

    View details for PubMedID 23687895

  • Effects of mammalian herbivore declines on plant communities: observations and experiments in an African savanna. The Journal of ecology Young, H. S., McCauley, D. J., Helgen, K. M., Goheen, J. R., Otárola-Castillo, E. n., Palmer, T. M., Pringle, R. M., Young, T. P., Dirzo, R. n. 2013; 101 (4): 1030–41


    1. Herbivores influence the structure and composition of terrestrial plant communities. However, responses of plant communities to herbivory are variable and depend on environmental conditions, herbivore identity and herbivore abundance. As anthropogenic impacts continue to drive large declines in wild herbivores, understanding the context dependence of herbivore impacts on plant communities becomes increasingly important. 2. Exclosure experiments are frequently used to assess how ecosystems reorganize in the face of large wild herbivore defaunation. Yet in many landscapes, declines in large wildlife are often accompanied by other anthropogenic activities, especially land conversion to livestock production. In such cases, exclosure experiments may not reflect typical outcomes of human-driven extirpations of wild herbivores. 3. Here, we examine how plant community responses to changes in the identity and abundance of large herbivores interact with abiotic factors (rainfall and soil properties). We also explore how effects of wild herbivores on plant communities differ between large-scale herbivore exclosures and landscape sites where anthropogenic activity has caused wildlife declines, often accompanied by livestock increases. 4. Abiotic context modulated the responses of plant communities to herbivore declines with stronger effect sizes in lower-productivity environments. Also, shifts in plant community structure, composition and species richness following wildlife declines differed considerably between exclosure experiments and landscape sites in which wild herbivores had declined and were often replaced by livestock. Plant communities in low wildlife landscape sites were distinct in both composition and physical structure from both exclosure and control sites in experiments. The power of environmental (soil and rainfall) gradients in influencing plant response to herbivores was also greatly dampened or absent in the landscape sites. One likely explanation for these observed differences is the compensatory effect of livestock associated with the depression or extirpation of wildlife. 5.Synthesis. Our results emphasize the importance of abiotic environmental heterogeneity in modulating the effects of mammalian herbivory on plant communities and the importance of such covariation in understanding effects of wild herbivore declines. They also suggest caution when extrapolating results from exclosure experiments to predict the consequences of defaunation as it proceeds in the Anthropocene.

    View details for PubMedID 24014216

    View details for PubMedCentralID PMC3758959

  • Plant defense, herbivory, and the growth of Cordia alliodora trees and their symbiotic Azteca ant colonies OECOLOGIA Pringle, E. G., Dirzo, R., Gordon, D. M. 2012; 170 (3): 677-685


    The effects of herbivory on plant fitness are integrated over a plant's lifetime, mediated by ontogenetic changes in plant defense, tolerance, and herbivore pressure. In symbiotic ant-plant mutualisms, plants provide nesting space and food for ants, and ants defend plants against herbivores. The benefit to the plant of sustaining the growth of symbiotic ant colonies depends on whether defense by the growing ant colony outpaces the plant's growth in defendable area and associated herbivore pressure. These relationships were investigated in the symbiotic mutualism between Cordia alliodora trees and Azteca pittieri ants in a Mexican tropical dry forest. As ant colonies grew, worker production remained constant relative to ant-colony size. As trees grew, leaf production increased relative to tree size. Moreover, larger trees hosted lower densities of ants, suggesting that ant-colony growth did not keep pace with tree growth. On leaves with ants experimentally excluded, herbivory per unit leaf area increased exponentially with tree size, indicating that larger trees experienced higher herbivore pressure per leaf area than smaller trees. Even with ant defense, herbivory increased with tree size. Therefore, although larger trees had larger ant colonies, ant density was lower in larger trees, and the ant colonies did not provide sufficient defense to compensate for the higher herbivore pressure in larger trees. These results suggest that in this system the tree can decrease herbivory by promoting ant-colony growth, i.e., sustaining space and food investment in ants, as long as the tree continues to grow.

    View details for DOI 10.1007/s00442-012-2340-x

    View details for Web of Science ID 000309866200009

    View details for PubMedID 22562422

  • Averting biodiversity collapse in tropical forest protected areas NATURE Laurance, W. F., Useche, D. C., Rendeiro, J., Kalka, M., Bradshaw, C. J., Sloan, S. P., Laurance, S. G., Campbell, M., Abernethy, K., Alvarez, P., Arroyo-Rodriguez, V., Ashton, P., Benitez-Malvido, J., Blom, A., Bobo, K. S., Cannon, C. H., Cao, M., Carroll, R., Chapman, C., Coates, R., Cords, M., Danielsen, F., De Dijn, B., Dinerstein, E., Donnelly, M. A., Edwards, D., Edwards, F., Farwig, N., Fashing, P., Forget, P., Foster, M., Gale, G., Harris, D., Harrison, R., Hart, J., Karpanty, S., Kress, W. J., Krishnaswamy, J., Logsdon, W., Lovett, J., Magnusson, W., Maisels, F., Marshall, A. R., McClearn, D., Mudappa, D., Nielsen, M. R., Pearson, R., Pitman, N., van der Ploeg, J., Plumptre, A., Poulsen, J., Quesada, M., Rainey, H., Robinson, D., Roetgers, C., Rovero, F., Scatena, F., Schulze, C., Sheil, D., Struhsaker, T., Terborgh, J., Thomas, D., Timm, R., Urbina-Cardona, J. N., Vasudevan, K., Wright, S. J., Arias-G, J. C., Arroyo, L., Ashton, M., Auzel, P., Babaasa, D., Babweteera, F., Baker, P., Banki, O., Bass, M., Bila-Isia, I., Blake, S., Brockelman, W., Brokaw, N., Bruehl, C. A., Bunyavejchewin, S., Chao, J., Chave, J., Chellam, R., Clark, C. J., Clavijo, J., Congdon, R., Corlett, R., Dattaraja, H. S., Dave, C., Davies, G., Beisiegel, B. d., da Silva, R. d., Di Fiore, A., Diesmos, A., Dirzo, R., Doran-Sheehy, D., Eaton, M., Emmons, L., Estrada, A., Ewango, C., Fedigan, L., Feer, F., Fruth, B., Willis, J. G., Goodale, U., Goodman, S., Guix, J. C., Guthiga, P., Haber, W., Hamer, K., Herbinger, I., Hill, J., Huang, Z., Sun, I. F., Ickes, K., Itoh, A., Ivanauskas, N., Jackes, B., Janovec, J., Janzen, D., Jiangming, M., Jin, C., Jones, T., Justiniano, H., Kalko, E., Kasangaki, A., Killeen, T., King, H., Klop, E., Knott, C., Kone, I., Kudavidanage, E., Ribeiro, J. L., Lattke, J., Laval, R., Lawton, R., Leal, M., Leighton, M., Lentino, M., Leonel, C., Lindsell, J., Ling-Ling, L., Linsenmair, K. E., Losos, E., Lugo, A., Lwanga, J., Mack, A. L., Martins, M., McGraw, W. S., McNab, R., Montag, L., Thompson, J. M., Nabe-Nielsen, J., Nakagawa, M., Nepal, S., Norconk, M., Novotny, V., O'Donnell, S., Opiang, M., Ouboter, P., Parker, K., Parthasarathy, N., Pisciotta, K., Prawiradilaga, D., Pringle, C., Rajathurai, S., Reichard, U., Reinartz, G., Renton, K., Reynolds, G., Reynolds, V., Riley, E., Roedel, M., Rothman, J., Round, P., Sakai, S., Sanaiotti, T., Savini, T., Schaab, G., Seidensticker, J., Siaka, A., Silman, M. R., Smith, T. B., de Almeida, S. S., Sodhi, N., Stanford, C., Stewart, K., Stokes, E., Stoner, K. E., Sukumar, R., Surbeck, M., Tobler, M., Tscharntke, T., Turkalo, A., Umapathy, G., Van Weerd, M., Rivera, J. V., Venkataraman, M., Venn, L., Verea, C., de Castilho, C. V., Waltert, M., Wang, B., Watts, D., Weber, W., West, P., Whitacre, D., Whitney, K., Wilkie, D., Williams, S., Wright, D. D., Wright, P., Xiankai, L., Yonzon, P., Zamzani, F. 2012; 489 (7415): 290-?


    The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon. With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses. As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 31 functional groups of species and 21 potential drivers of environmental change, for 60 protected areas stratified across the world’s major tropical regions. Our analysis reveals great variation in reserve ‘health’: about half of all reserves have been effective or performed passably, but the rest are experiencing an erosion of biodiversity that is often alarmingly widespread taxonomically and functionally. Habitat disruption, hunting and forest-product exploitation were the strongest predictors of declining reserve health. Crucially, environmental changes immediately outside reserves seemed nearly as important as those inside in determining their ecological fate, with changes inside reserves strongly mirroring those occurring around them. These findings suggest that tropical protected areas are often intimately linked ecologically to their surrounding habitats, and that a failure to stem broad-scale loss and degradation of such habitats could sharply increase the likelihood of serious biodiversity declines.

    View details for DOI 10.1038/nature11318

    View details for Web of Science ID 000308635900041

    View details for PubMedID 22832582

  • Effects of Spatial Subsidies and Habitat Structure on the Foraging Ecology and Size of Geckos PLOS ONE Briggs, A. A., Young, H. S., McCauley, D. J., Hathaway, S. A., Dirzo, R., Fisher, R. N. 2012; 7 (8)


    While it is well established that ecosystem subsidies--the addition of energy, nutrients, or materials across ecosystem boundaries--can affect consumer abundance, there is less information available on how subsidy levels may affect consumer diet, body condition, trophic position, and resource partitioning among consumer species. There is also little information on whether changes in vegetation structure commonly associated with spatial variation in subsidies may play an important role in driving consumer responses to subsidies. To address these knowledge gaps, we studied changes in abundance, diet, trophic position, size, and body condition of two congeneric gecko species (Lepidodactylus spp.) that coexist in palm dominated and native (hereafter dicot dominated) forests across the Central Pacific. These forests differ strongly both in the amount of marine subsidies that they receive from seabird guano and carcasses, and in the physical structure of the habitat. Contrary to other studies, we found that subsidy level had no impact on the abundance of either gecko species; it also did not have any apparent effects on resource partitioning between species. However, it did affect body size, dietary composition, and trophic position of both species. Geckos in subsidized, dicot forests were larger, had higher body condition and more diverse diets, and occupied a much higher trophic position than geckos found in palm dominated, low subsidy level forests. Both direct variation in subsidy levels and associated changes in habitat structure appear to play a role in driving these responses. These results suggest that variation in subsidy levels may drive important behavioral responses in predators, even when their numerical response is limited. Strong changes in trophic position of consumers also suggest that subsidies may drive increasingly complex food webs, with longer overall food chain length.

    View details for DOI 10.1371/journal.pone.0041364

    View details for PubMedID 22899995

  • Diversification and phylogeographic structure in widespread Azteca plant-ants from the northern Neotropics MOLECULAR ECOLOGY Pringle, E. G., Ramirez, S. R., Bonebrake, T. C., Gordon, D. M., Dirzo, R. 2012; 21 (14): 3576-3592


    The Neotropical myrmecophytic tree Cordia alliodora hosts symbiotic Azteca ants in most of its widespread range. The taxonomy of the genus Azteca is notoriously difficult, which has frequently obscured species identity in ecological studies. We used sequence data from one mitochondrial and four nuclear loci to infer phylogenetic relationships, patterns of geographic distribution, and timing of diversification for 182 colonies of five C. alliodora-dwelling Azteca species from Mexico to Colombia. All morphological species were recovered as monophyletic, but we identified at least five distinct genetic lineages within the most abundant and specialized species, Azteca pittieri. Mitochondrial and nuclear data were concordant at the species level, but not within species. Divergence time analyses estimated that C. alliodora-dwelling Azteca shared a common ancestor approximately 10-22million years ago, prior to the proposed arrival of the host tree in Middle America. Diversification in A. pittieri occurred in the Pleistocene and was not correlated with geographic distance, which suggests limited historical gene flow among geographically restricted populations. This contrasts with the previously reported lack of phylogeographic structure at this spatial scale in the host tree. Climatic niches, and particularly precipitation-related variables, did not overlap between the sites occupied by northern and southern lineages of A. pittieri. Together, these results suggest that restricted gene flow among ant populations may facilitate local adaptation to environmental heterogeneity. Differences in population structure between the ants and their host trees may profoundly affect the evolutionary dynamics of this widespread ant-plant mutualism.

    View details for DOI 10.1111/j.1365-294X.2012.05618.x

    View details for Web of Science ID 000306087100017

    View details for PubMedID 22646059

  • From wing to wing: the persistence of long ecological interaction chains in less-disturbed ecosystems SCIENTIFIC REPORTS McCauley, D. J., DeSalles, P. A., Young, H. S., Dunbar, R. B., Dirzo, R., Mills, M. M., Micheli, F. 2012; 2


    Human impact on biodiversity usually is measured by reduction in species abundance or richness. Just as important, but much more difficult to discern, is the anthropogenic elimination of ecological interactions. Here we report on the persistence of a long ecological interaction chain linking diverse food webs and habitats in the near-pristine portions of a remote Pacific atoll. Using biogeochemical assays, animal tracking, and field surveys we show that seabirds roosting on native trees fertilize soils, increasing coastal nutrients and the abundance of plankton, thus attracting manta rays to native forest coastlines. Partnered observations conducted in regions of this atoll where native trees have been replaced by human propagated palms reveal that this complex interaction chain linking trees to mantas readily breaks down. Taken together these findings provide a compelling example of how anthropogenic disturbance may be contributing to widespread reductions in ecological interaction chain length, thereby isolating and simplifying ecosystems.

    View details for DOI 10.1038/srep00409

    View details for Web of Science ID 000304393800001

    View details for PubMedID 22624091

    View details for PubMedCentralID PMC3354671

  • The effect of land use change and ecotourism on biodiversity: a case study of Manuel Antonio, Costa Rica, from 1985 to 2008 LANDSCAPE ECOLOGY Broadbent, E. N., Zambrano, A. M., Dirzo, R., Durham, W. H., Driscoll, L., Gallagher, P., Salters, R., Schultz, J., Colmenares, A., Randolph, S. G. 2012; 27 (5): 731-744
  • Consequences of Fragmentation of Tropical Moist Forest for Birds and Their Role in Predation of Herbivorous Insects BIOTROPICA Ruiz-Guerra, B., Renton, K., Dirzo, R. 2012; 44 (2): 228-236
  • Intersexual comparison of DNA content by flow cytometry, and chromosome number in four dioecious Chamaedorea palms from Mexico CARYOLOGIA Cepeda-Cornejo, V., Palomino, G., Mendez, I., Dirzo, R. 2012; 65 (4): 263-270


    Elucidating the factors that determine the abundance and distribution of species remains a central goal of ecology. It is well recognized that genetic differences among individual species can affect the distribution and species interactions of dependent taxa, but the ecological effects of genetic differences on taxa of the same trophic level remain much less understood. Our goal was to test the hypothesis that differences between related overstory tree species and their hybrids can influence the understory plant community in wild settings.We conducted vegetation surveys in a riparian community with the overstory dominated by Populus fremontii, P. angustifolia, and their natural hybrids (referred to as cross types) along the Weber River in north central Utah, USA. Understory diversity and community composition, as well as edaphic properties, were compared under individual trees.Diversity metrics differ under the three different tree cross types such that a greater species richness, diversity, and cover of understory plants exist under the hybrids compared with either of the parental taxa (30-54%, 40-48%, and 35-74% greater, respectively). The community composition of the understory also varied by cross type, whereby additional understory plant species cluster with hybrids, not with parental species.Genetic composition dictated by hybridization in the overstory can play a role in structuring the associated understory plants in natural communities-where a hybridized overstory correlates with a species-rich understory-and thus can have cascading effects on community members of the same trophic level. The underlying mechanism requires further investigation.

    View details for DOI 10.3732/ajb.1100137

    View details for Web of Science ID 000295888800018

    View details for PubMedID 21960550

  • Analysis of a hyper-diverse seed dispersal network: modularity and underlying mechanisms ECOLOGY LETTERS Donatti, C. I., Guimaraes, P. R., Galetti, M., Pizo, M. A., Marquitti, F. M., Dirzo, R. 2011; 14 (8): 773-781


    Mutualistic interactions involving pollination and ant-plant mutualistic networks typically feature tightly linked species grouped in modules. However, such modularity is infrequent in seed dispersal networks, presumably because research on those networks predominantly includes a single taxonomic animal group (e.g. birds). Herein, for the first time, we examine the pattern of interaction in a network that includes multiple taxonomic groups of seed dispersers, and the mechanisms underlying modularity. We found that the network was nested and modular, with five distinguishable modules. Our examination of the mechanisms underlying such modularity showed that plant and animal trait values were associated with specific modules but phylogenetic effect was limited. Thus, the pattern of interaction in this network is only partially explained by shared evolutionary history. We conclude that the observed modularity emerged by a combination of phylogenetic history and trait convergence of phylogenetically unrelated species, shaped by interactions with particular types of dispersal agents.

    View details for DOI 10.1111/j.1461-0248.2011.01639.x

    View details for Web of Science ID 000292864400007

    View details for PubMedID 21699640

  • Differential diameter-size effects of forest management on tree species richness and community structure: implications for conservation BIODIVERSITY AND CONSERVATION Gutierrez-Granados, G., Perez-Salicrup, D. R., Dirzo, R. 2011; 20 (7): 1571-1585
  • Distinct Leaf-trait Syndromes of Evergreen and Deciduous Trees in a Seasonally Dry Tropical Forest BIOTROPICA Pringle, E. G., Adams, R. I., Broadbent, E., Busby, P. E., Donatti, C. I., Kurten, E. L., Renton, K., Dirzo, R. 2011; 43 (3): 299-308
  • A Novel Method to Improve Individual Animal Identification Based on Camera-Trapping Data JOURNAL OF WILDLIFE MANAGEMENT Mendoza, E., Martineau, P. R., Brenner, E., Dirzo, R. 2011; 75 (4): 973-979

    View details for DOI 10.1002/jwmg.120

    View details for Web of Science ID 000291818100025



    Seabirds often cause significant changes to soil properties, and seabird-dominated systems often host unique plant communities. This study experimentally (1) examined species-specific responses to seabird guano gradients, (2) considered the role that differential functional traits among species play in altering plant response to guano, and (3) investigated the implications of seabird guano on range-expanding species.Using a greenhouse fertilization experiment, we examined how guano fertilization affects the growth and functional traits of four tree species dominant in the Pacific Islands: Cocos nucifera, Pisonia grandis, Scaevola sericea, and Tournefortia argentea. In these systems, seabirds are frequently found in association with three of these four species; the remaining species, C. nucifera, is a recently proliferating species commonly found in the region but rarely associated with seabirds.We determined that responses to guano addition differed significantly between species in ways that were consistent with predictions based on differing functional traits among species. Notably, we demonstrated that C. nucifera showed no growth responses to guano additions, whereas all seabird-associated plants showed strong responses.These results provide experimental evidence of differential species response to guano additions, suggesting that differences in species functional traits may contribute to changes in plant communities in seabird-dominated areas, with seabird-associated species garnering performance advantages in these high-nutrient environments. Among these species, results also suggest that C. nucifera may have a competitive advantage in low-nutrient environments, providing an unusual example of how a range-expanding plant species can profit from low-nutrient environments.

    View details for DOI 10.3732/ajb.1000159

    View details for Web of Science ID 000286884500015

    View details for PubMedID 21613110

  • Indirect benefits of symbiotic coccoids for an ant-defended myrmecophytic tree ECOLOGY Pringle, E. G., Dirzo, R., Gordon, D. M. 2011; 92 (1): 37-46


    The net benefits of mutualism depend directly on the costs and effectiveness of mutualistic services and indirectly on the interactions that affect those services. We examined interactions among Cordia alliodora myrmecophytic trees, their symbiotic ants Azteca pittieri, coccoid hemipterans, and foliar herbivores in two Neotropical dry forests. The tree makes two investments in symbiotic ants: it supplies nesting space, as domatia, and it provides phloem to coccoids, which then produce honeydew that is consumed by ants. Although higher densities of coccoids should have higher direct costs for trees, we asked whether higher densities of coccoids can also have higher indirect benefits for trees by increasing the effectiveness of ant defense against foliar herbivores. We found that trees benefited from ant defense against herbivores. Ants defended trees effectively only when colonies reached high densities within trees, and ant and coccoid densities within trees were strongly positively correlated. The benefits of reduced foliar herbivory by larger ant colonies were therefore indirectly controlled by the number of coccoids. Coccoid honeydew supply also affected per capita ant aggression against tree herbivores. Ants experimentally fed a carbohydrate-rich diet, analogous to sugar obtained from coccoids, were more aggressive against caterpillars per capita than ants fed a carbohydrate-poor diet. Ant defense was more effective on more valuable and vulnerable young leaves than on older leaves. Young domatia, associated with young leaves, contained higher coccoid densities than older domatia, which suggests that coccoids may also drive spatially favorable ant defense of the tree. If higher investments by one mutualistic partner are tied to higher benefits received from the other, there may be positive feedback between partners that will stabilize the mutualism. These results suggest that higher investment by trees in coccoids leads to more effective defense by ants against the tree's foliar herbivores.

    View details for Web of Science ID 000289552200006

    View details for PubMedID 21560674

  • Effects of forest fragmentation on assemblages of pollinators and floral visitors to male- and female-phase inflorescences of Astrocaryum mexicanum (Arecaceae) in a Mexican rain forest JOURNAL OF TROPICAL ECOLOGY Aguirre, A., Guevara, R., Dirzo, R. 2011; 27: 25-33
  • The coconut palm, Cocos nucifera, impacts forest composition and soil characteristics at Palmyra Atoll, Central Pacific JOURNAL OF VEGETATION SCIENCE Young, H. S., Raab, T. K., McCauley, D. J., Briggs, A. A., Dirzo, R. 2010; 21 (6): 1058-1068
  • Plant stages with biotic, indirect defences are more palatable and suffer less herbivory than their undefended counterparts BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY Llandres, A. L., Rodriguez-Girones, M. A., Dirzo, R. 2010; 101 (3): 536-543
  • Delineation of biogeomorphic land units across a tropical natural and humanized terrain in Los Tuxtlas, Veracruz, Mexico GEOMORPHOLOGY Concepcion Garcia-Aguirre, M., Alvarez, R., Dirzo, R., Ortiz, M. A., Eng, M. M. 2010; 121 (3-4): 245-256
  • Experimental defoliation affects male but not female reproductive performance of the tropical monoecious plant Croton suberosus (Euphorbiaceae) ANNALS OF BOTANY Narbona, E., Dirzo, R. 2010; 106 (2): 359-369


    Monoecious plants have the capacity to allocate resources separately to male and female functions more easily than hermaphrodites. This can be advantageous against environmental stresses such as leaf herbivory. However, studies showing effects of herbivory on male and female functions and on the interaction with the plant's pollinators are limited, particularly in tropical plants. Here, the effects of experimental defoliation were examined in the monoecious shrub Croton suberosus (Euphorbiaceae), a wasp-pollinated species from a Mexican tropical dry forest.Three defoliation treatments were applied: 0 % (control), 25 % (low) or 75 % (high) of plant leaf area removed. Vegetative (production of new leaves) and reproductive (pistillate and staminate flower production, pollen viability, nectar production, fruit set, and seed set) performance variables, and the abundance and activity of floral visitors were examined.Defoliated plants overcompensated for tissue loss by producing more new leaves than control plants. Production of staminate flowers gradually decreased with increasing defoliation and the floral sex ratio (staminate : pistillate flowers) was drastically reduced in high-defoliation plants. In contrast, female reproductive performance (pistillate flower production, fruit set and seed set) and pollinator visitation and abundance were not impacted by defoliation.The asymmetrical effects of defoliation on male and female traits of C. suberosus may be due to the temporal and spatial flexibility in the allocation of resources deployed by monoecious plants. We posit that this helps to maintain the plant's pollination success in the face of leaf herbivory stress.

    View details for DOI 10.1093/aob/mcq117

    View details for Web of Science ID 000280264400012

    View details for PubMedID 20519239



    Typically, plant-pollinator interactions are recognized as mutualistic relationships. Flower visitors, however, can potentially play multiple roles. The floral nectar in Croton suberosus has been proposed to operate as a reward for predators, especially the wasp Polistes instabilis (Vespidae), which kills herbivorous insects, while the plant has been thought to be mainly wind-pollinated. In this study, we reassessed the pollination mode of C. suberosus and the possible role of its flower visitors. Pollinator exclusion experiments demonstrated that C. suberosus should be considered a strictly entomophilous species. Inflorescences of C. suberosus were visited by a diverse entomofauna involving 28 taxa belonging to six orders; however, wasps and bees were the only visitors that carried C. suberosus pollen. The visitation rate of wasps was approximately four times that of bees. This observation, combined with the fact that the small size of bees makes effective contact of their bodies with the stigma difficult, strongly suggests that large wasps are responsible for most of the effective pollination of C. suberosus. Among the wasp visitors, P. instabilis seems to be one of the most important. These findings expose an unusual plant-insect interaction, in which the plant provides nectar and wasps pollinate and defend the plant.

    View details for DOI 10.3732/ajb.0900259

    View details for Web of Science ID 000276045500014

    View details for PubMedID 21622429

  • Sex-Related Differences in Reproductive Allocation, Growth, Defense and Herbivory in Three Dioecious Neotropical Palms PLOS ONE Cepeda-Cornejo, V., Dirzo, R. 2010; 5 (3)


    Frequently, in dioecious plants, female plants allocate more resources to reproduction than male plants. Therefore it is expected that asymmetrical allocation to reproduction may lead to a reproduction-growth tradeoff, whereby female plants grow less than male plants, but invest more in defenses and thus experience lower herbivory than male plants.We tested these expectations by comparing resource allocation to reproduction, growth and defense and its consequences on herbivory in three sympatric dioecious Chamaedorea palms (C. alternans, C. pinnatifrons and C. ernesti-augusti) using a pair-wise design (replicated male/female neighboring plants) in a Mexican tropical rain forest. Our findings support the predictions. Biomass allocation to reproduction in C. pinnatifrons was 3-times higher in female than male plants, consistent with what is known in C. alternans and C. ernesti-augusti. Growth (height and leaf production rate and biomass production) was higher in male plants of all three species. Female plants of the three species had traits that suggest greater investment in defense, as they had 4-16% tougher leaves, and 8-18% higher total phenolic compounds concentration. Accordingly, female plants sustained 53-78% lower standing herbivory and 49-87% lower herbivory rates than male plants.Our results suggests that resource allocation to reproduction in the studied palms is more costly to female plants and this leads to predictable intersexual differences in growth, defense and herbivory. We conclude that resource allocation to reproduction in plants can have important consequences that influence their interaction with herbivores. Since herbivory is recognized as an important selective force in plants, these results are of significance to our understanding of plant defense evolution.

    View details for DOI 10.1371/journal.pone.0009824

    View details for Web of Science ID 000275894400024

    View details for PubMedID 20352113

  • Importance of the lilac-crowned parrot in pre-dispersal seed predation of Astronium graveolens in a Mexican tropical dry forest JOURNAL OF TROPICAL ECOLOGY Ines Villasenor-Sanchez, E., Dirzo, R., Renton, K. 2010; 26: 227-236
  • Plants cause ecosystem nutrient depletion via the interruption of bird-derived spatial subsidies PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Young, H. S., McCauley, D. J., Dunbar, R. B., Dirzo, R. 2010; 107 (5): 2072-2077


    Plant introductions and subsequent community shifts are known to affect nutrient cycling, but most such studies have focused on nutrient enrichment effects. The nature of plant-driven nutrient depletions and the mechanisms by which these might occur are relatively poorly understood. In this study we demonstrate that the proliferation of the commonly introduced coconut palm, Cocos nucifera, interrupts the flow of allochthonous marine subsidies to terrestrial ecosystems via an indirect effect: impact on birds. Birds avoid nesting or roosting in C. nucifera, thus reducing the critical nutrient inputs they bring from the marine environment. These decreases in marine subsidies then lead to reductions in available soil nutrients, decreases in leaf nutrient quality, diminished leaf palatability, and reduced herbivory. This nutrient depletion pathway contrasts the more typical patterns of nutrient enrichment that follow plant species introductions. Research on the effects of spatial subsidy disruptions on ecosystems has not yet examined interruptions driven by changes within the recipient community, such as plant community shifts. The ubiquity of coconut palm introductions across the tropics and subtropics makes these observations particularly noteworthy. Equally important, the case of C. nucifera provides a strong demonstration of how plant community changes can dramatically impact the supply of allochthonous nutrients and thereby reshape energy flow in ecosystems.

    View details for DOI 10.1073/pnas.0914169107

    View details for Web of Science ID 000274296300049

    View details for PubMedID 20133852

    View details for PubMedCentralID PMC2836700

  • Insect herbivory declines with forest fragmentation and covaries with plant regeneration mode: evidence from a Mexican tropical rain forest OIKOS Ruiz-Guerra, B., Guevara, R., Mariano, N. A., Dirzo, R. 2010; 119 (2): 317-325
  • Niche partitioning among and within sympatric tropical seabirds revealed by stable isotope analysis MARINE ECOLOGY PROGRESS SERIES Young, H. S., McCauley, D. J., Dirzo, R., Dunbar, R. B., Shaffer, S. A. 2010; 416: 285-294

    View details for DOI 10.3354/meps08756

    View details for Web of Science ID 000283446400023

  • Resource partitioning by species but not sex in sympatric boobies in the central Pacific Ocean MARINE ECOLOGY PROGRESS SERIES Young, H. S., Shaffer, S. A., McCauley, D. J., Foley, D. G., Dirzo, R., Block, B. A. 2010; 403: 291-301

    View details for DOI 10.3354/meps08478

    View details for Web of Science ID 000276799000024

  • Prevalence of Tree Regeneration by Sprouting and Seeding Along a Rainfall Gradient in Hawai'i BIOTROPICA Busby, P. E., Vitousek, P., Dirzo, R. 2010; 42 (1): 80-86
  • Indirect effects of timber extraction on plant recruitment and diversity via reductions in abundance of frugivorous spider monkeys JOURNAL OF TROPICAL ECOLOGY Gutierrez-Granados, G., Dirzo, R. 2010; 26: 45-52


    Tolerance, the capacity of plants to withstand attack by animals, as opposed to resistance, has been poorly examined in the context of seed predation. We investigated the role that the seed mass of the large-seeded endemic tree Aesculus californica plays as a tolerance trait to rodent attack by comparing, under greenhouse conditions, patterns of germination, and subsequent seedling growth, of seeds with a wide range of natural damage. Germination percentage was reduced by 50% and time to germination by 64% in attacked compared to intact seeds, and germination probability was negatively correlated with damage. Seedlings that emerged from intact seeds were taller and bore more leaves than those from damaged seeds. This species' large seed mass favors tolerance to damage because heavily damaged seeds are able to germinate and produce seedlings. This finding is significant given that seeds of this species are known to contain chemical compounds toxic to vertebrates, a resistance trait. We posit that this combination of tolerance and resistance traits might be a particularly effective antipredation strategy when seeds are exposed to a variety of vertebrate predators.

    View details for DOI 10.3732/ajb.0800297

    View details for Web of Science ID 000267870800005

    View details for PubMedID 21628274

  • Morphological variation in the flowers of Jacaratia mexicana A. DC. (Caricaceae), a subdioecious tree PLANT BIOLOGY Aguirre, A., Vallejo-Marin, M., Piedra-Malagon, E. M., Cruz-Ortega, R., Dirzo, R. 2009; 11 (3): 417-424


    The Caricaceae is a small family of tropical trees and herbs in which most species are dioecious. In the present study, we extend our previous work on dioecy in the Caricaceae, characterising the morphological variation in sexual expression in flowers of the dioecious tree Jacaratia mexicana. We found that, in J. mexicana, female plants produce only pistillate flowers, while male plants are sexually variable and can bear three different types of flowers: staminate, pistillate and perfect. To characterise the distinct types of flowers, we measured 26 morphological variables. Our results indicate that: (i) pistillate flowers from male trees carry healthy-looking ovules and are morphologically similar, although smaller than, pistillate flowers on female plants; (ii) staminate flowers have a rudimentary, non-functional pistil and are the only flowers capable of producing nectar; and (iii) perfect flowers produce healthy-looking ovules and pollen, but have smaller ovaries than pistillate flowers and fewer anthers than staminate flowers, and do not produce nectar. The restriction of sexual variation to male trees is consistent with the evolutionary path of dioecy from hermaphrodite ancestors through the initial invasion of male-sterile plants and a subsequent gradual reduction in female fertility in cosexual individuals (gynodioecy pathway), but further work is needed to confirm this hypothesis.

    View details for DOI 10.1111/j.1438-8677.2008.00154.x

    View details for Web of Science ID 000265015300015

    View details for PubMedID 19470112

  • Effects of fragmentation on pollinator abundance and fruit set of an abundant understory palm in a Mexican tropical forest BIOLOGICAL CONSERVATION Aguirre, A., Dirzo, R. 2008; 141 (2): 375-384
  • Effects of Amazonian forest fragmentation on the interaction between plants, insect herbivores, and their natural enemies JOURNAL OF TROPICAL ECOLOGY Faveri, S. B., Vasconcelos, H. L., Dirzo, R. 2008; 24: 57-64
  • Seed-size variation determines interspecific differential predation by mammals in a neotropical rain forest OIKOS Mendoza, E., Dirzo, R. 2007; 116 (11): 1841-1852
  • Ontogenetic switches from plant resistance to tolerance: minimizing costs with age? ECOLOGY LETTERS Boege, K., Dirzo, R., Siemens, D., Brown, P. 2007; 10 (3): 177-187


    Changes in herbivory and resource availability during a plant's development should promote ontogenetic shifts in resistance and tolerance, if the costs and benefits of these basic strategies also change as plants develop. We proposed and tested a general model to detect the expression of ontogenetic tradeoffs for these two alternative anti-herbivory strategies in Raphanus sativus. We found that ontogenetic trajectories occur in both resistance and tolerance but in opposite directions. The juvenile stage was more resistant but less tolerant than the reproductive stage. The ontogenetic switch from resistance to tolerance was consistent with the greater vulnerability of young plants to leaf damage and with the costs of resistance and tolerance found at each stage. We posit that the ontogenetic perspective presented here will be helpful in resolving the current debate on the existence and detection of a general resistance-tolerance tradeoff.

    View details for DOI 10.1111/j.1461-0248.2006.01012.x

    View details for Web of Science ID 000244227800003

    View details for PubMedID 17305801

  • Floristic diversity of sabal palmetto woodland: an endemic and endangered vegetation type from Mexico BIODIVERSITY AND CONSERVATION Lopez, J. C., Dirzo, R. 2007; 16 (3): 807-825
  • Variation in sexual expression in Jacaratia mexicana (Caricaceae) in southern Mexico: Frequency and relative seed performance of fruit-producing males BIOTROPICA Aguirre, A., Vallejo-Marin, M., Salazar-Goroztieta, L., Arias, D. M., Dirzo, R. 2007; 39 (1): 79-86
  • Biased seed rain in forest edges: Evidence from the Brazilian Atlantic forest BIOLOGICAL CONSERVATION de Melo, F. P., Dirzo, R., Tabarelli, M. 2006; 132 (1): 50-60
  • Simulated seed predation reveals a variety of germination responses of neotropical rain forest species AMERICAN JOURNAL OF BOTANY Vallejo-Marin, M., DOMINGUEZ, C. A., Dirzo, R. 2006; 93 (3): 369-376


    Seed predation, an omnipresent phenomenon in tropical rain forests, is an important determinant of plant recruitment and forest regeneration. Although seed predation destroys large amounts of the seed crop of numerous tropical species, in many cases individual seed damage is only partial. The extent to which partial seed predation affects the recruitment of new individuals in the population depends on the type and magnitude of alteration of the germination behavior of the damaged seeds. We analyzed the germination dynamics of 11 tropical woody species subject to increasing levels of simulated seed predation (0-10% seed mass removal). Germination response to seed damage varied considerably among species but could be grouped into four distinct types: (1) complete inability to germinate under damage ≥1%, (2) no effect on germination dynamics, (3) reduced germination with increasing damage, and (4) reduced final germination but faster germination with increasing damage. We conclude that partial seed predation is often nonlethal and argue that different responses to predation may represent different proximal mechanisms for coping with partial damage, with potential to shape, in the long run, morphological and physiological adaptations in tropical, large-seeded species.

    View details for Web of Science ID 000235986100006

    View details for PubMedID 21646197

  • A quantitative analysis of forest fragmentation in Los Tuxtlas, southeast Mexico: patterns and implications for conservation REVISTA CHILENA DE HISTORIA NATURAL Mendoza, E., Fay, J., Dirzo, R. 2005; 78 (3): 451-467
  • Myrmecophily: Plants with their own army INTERCIENCIA Del Val, E., Dirzo, R. 2004; 29 (12): 673-?
  • Diversity of gall-inducing insects in a Mexican tropical dry forest: the importance of plant species richness, life-forms, host plant age and plant density JOURNAL OF ECOLOGY Cuevas-Reyes, P., Quesada, M., Hanson, P., Dirzo, R., Oyama, K. 2004; 92 (4): 707-716
  • Intraspecific variation in growth, defense and herbivory in Dialium guianense (Caesalpiniaceae) mediated by edaphic heterogeneity PLANT ECOLOGY Boege, K., Dirzo, R. 2004; 175 (1): 59-69
  • Global state of biodiversity and loss Annual Review of Environment and Natural Resources Rodolfo Dirzo, Peter Raven 2003; 28: 137-167
  • Does ontogeny cause changes in the defensive strategies of the myrmecophyte Cecropia peltata? PLANT ECOLOGY Del Val, E., Dirzo, R. 2003; 169 (1): 35-41
  • The causes of land-use and land-cover change: moving beyond the myths GLOBAL ENVIRONMENTAL CHANGE-HUMAN AND POLICY DIMENSIONS Lambin, E. F., Turner, B. L., Geist, H. J., Agbola, S. B., Angelsen, A., Bruce, J. W., Coomes, O. T., Dirzo, R., Fischer, G., Folke, C., George, P. S., Homewood, K., Imbernon, J., Leemans, R., Li, X. B., Moran, E. F., Mortimore, M., Ramakrishnan, P. S., Richards, J. F., Skanes, H., STEFFEN, W., Stone, G. D., Svedin, U., Veldkamp, T. A., Vogel, C., Xu, J. C. 2001; 11 (4): 261-269
  • Biodiversity - Global biodiversity scenarios for the year 2100 SCIENCE Sala, O. E., Chapin, F. S., Armesto, J. J., Berlow, E., Bloomfield, J., Dirzo, R., Huber-Sanwald, E., Huenneke, L. F., Jackson, R. B., Kinzig, A., Leemans, R., Lodge, D. M., Mooney, H. A., Oesterheld, M., Poff, N. L., Sykes, M. T., Walker, B. H., Walker, M., Wall, D. H. 2000; 287 (5459): 1770-1774


    Scenarios of changes in biodiversity for the year 2100 can now be developed based on scenarios of changes in atmospheric carbon dioxide, climate, vegetation, and land use and the known sensitivity of biodiversity to these changes. This study identified a ranking of the importance of drivers of change, a ranking of the biomes with respect to expected changes, and the major sources of uncertainties. For terrestrial ecosystems, land-use change probably will have the largest effect, followed by climate change, nitrogen deposition, biotic exchange, and elevated carbon dioxide concentration. For freshwater ecosystems, biotic exchange is much more important. Mediterranean climate and grassland ecosystems likely will experience the greatest proportional change in biodiversity because of the substantial influence of all drivers of biodiversity change. Northern temperate ecosystems are estimated to experience the least biodiversity change because major land-use change has already occurred. Plausible changes in biodiversity in other biomes depend on interactions among the causes of biodiversity change. These interactions represent one of the largest uncertainties in projections of future biodiversity change.

    View details for Web of Science ID 000085775300030

  • Global biodiversity scenarios for the year 2100. Science Sala, O. E., Chapin, F. S., Armesto, J. J., Berlow, E., Bloomfield, J., Dirzo, R., Huber-Sanwald, E., Huenneke, L. F., Jackson, R. B., Kinzig, A., Leemans, R., Lodge, D. M., Mooney, H. A., Oesterheld, M., Poff, N. L., Sykes, M. T., Walker, B. H., Walker, M., Wall, D. H. 2000; 287 (5459): 1770-1774


    Scenarios of changes in biodiversity for the year 2100 can now be developed based on scenarios of changes in atmospheric carbon dioxide, climate, vegetation, and land use and the known sensitivity of biodiversity to these changes. This study identified a ranking of the importance of drivers of change, a ranking of the biomes with respect to expected changes, and the major sources of uncertainties. For terrestrial ecosystems, land-use change probably will have the largest effect, followed by climate change, nitrogen deposition, biotic exchange, and elevated carbon dioxide concentration. For freshwater ecosystems, biotic exchange is much more important. Mediterranean climate and grassland ecosystems likely will experience the greatest proportional change in biodiversity because of the substantial influence of all drivers of biodiversity change. Northern temperate ecosystems are estimated to experience the least biodiversity change because major land-use change has already occurred. Plausible changes in biodiversity in other biomes depend on interactions among the causes of biodiversity change. These interactions represent one of the largest uncertainties in projections of future biodiversity change.

    View details for PubMedID 10710299

  • Deforestation in Lacandonia (southeast Mexico): evidence for the declaration of the northernmost tropical hot-spot BIODIVERSITY AND CONSERVATION Mendoza, E., Dirzo, R. 1999; 8 (12): 1621-1641
  • Ecological science and the human predicament SCIENCE Bazzaz, F., Ceballos, G., Davis, M., Dirzo, R., Ehrlich, P. R., Eisner, T., Levin, S., Lawton, J. H., Lubchenco, J., Matson, P. A., Mooney, H. A., Raven, P. H., Roughgarden, J. E., Sarukhan, J., Tilman, G. D., Vitousek, P., Wall, D. H., Wilson, E. O., Woodwell, G. M. 1998; 282 (5390): 879-879
  • Logging drives contrasting animal body-size effects on tropical forest mammal communities FOREST ECOLOGY AND MANAGEMENT Gutierrez-Granados, G., Dirzo, R. 2021; 481
  • Jose Mario Molina: Life and legacy of a man who helped to save Earth's ozone layer. Proceedings of the National Academy of Sciences of the United States of America Dirzo, R., Fernandez, A. 2021; 118 (1)

    View details for DOI 10.1073/pnas.2023954118

    View details for PubMedID 33328336

  • Successful neighbour: Interactions of the generalist carnivore red fox with dogs, wolves and humans for continued survival in dynamic anthropogenic landscapes GLOBAL ECOLOGY AND CONSERVATION Reshamwala, H. S., Mahar, N., Dirzo, R., Habib, B. 2021; 25
  • Transgenerational Plasticity in Flower Color Induced by Caterpillars. Frontiers in plant science Sobral, M., Neylan, I. P., Narbona, E., Dirzo, R. 2021; 12: 617815


    Variation in flower color due to transgenerational plasticity could stem directly from abiotic or biotic environmental conditions. Finding a link between biotic ecological interactions across generations and plasticity in flower color would indicate that transgenerational effects of ecological interactions, such as herbivory, might be involved in flower color evolution. We conducted controlled experiments across four generations of wild radish (Raphanus sativus, Brassicaceae) plants to explore whether flower color is influenced by herbivory, and to determine whether flower color is associated with transgenerational chromatin modifications. We found transgenerational effects of herbivory on flower color, partly related to chromatin modifications. Given the presence of herbivory in plant populations worldwide, our results are of broad significance and contribute to our understanding of flower color evolution.

    View details for DOI 10.3389/fpls.2021.617815

    View details for PubMedID 33790921

  • Forest fragmentation and defaunation drive an unusual ecological cascade: Predation release, monkey population outburst and plant demographic collapse BIOLOGICAL CONSERVATION Portela, R. Q., Dirzo, R. 2020; 252
  • Matching species traits and microsites improves regeneration in mixed oak woodlands APPLIED VEGETATION SCIENCE Lopez-Sanchez, A., Johnson, I., Dirzo, R., Perea, R. 2020

    View details for DOI 10.1111/avsc.12536

    View details for Web of Science ID 000581128200001

  • Impacts of rodent eradication on seed predation and plant community biomass on a tropical atoll BIOTROPICA Kuile, A., Orr, D., Bui, A., Dirzo, R., Klope, M., McCauley, D., Motta, C., Young, H. 2020

    View details for DOI 10.1111/btp.12864

    View details for Web of Science ID 000575511100001

  • Biodiversity and ecosystem services in the Campo Rupestre: A road map for the sustainability of the hottest Brazilian biodiversity hotspot PERSPECTIVES IN ECOLOGY AND CONSERVATION Fernandes, G., Arantes-Garcia, L., Barbosa, M., Barbosa, N. U., Batista, E. L., Beiroz, W., Resende, F. M., Abrahao, A., Almada, E. D., Alves, E., Alves, N. J., Angrisano, P., Arista, M., Arroyo, J., Arruda, A., Bahia, T., Braga, L., Brito, L., Callisto, M., Caminha-Paiva, D., Carvalho, M., Conceicao, A., Costa, L. N., Cruz, A., Cunha-Blum, J., Dagevos, J., Dias, B. S., Pinto, V. D., Dirzo, R., Domingos, D., Echternacht, L., Fernandes, S., Figueira, J. C., Fiorini, C. F., Giulietti, A., Gomes, A., Gomes, V. M., Gontijo, B., Goulart, F., Guerra, T. J., Junqueira, P. A., Lima-Santos, D., Marques, J., Meira-Neto, J., Miola, D. B., Morellato, L. C., Negreiros, D., Neire, E., Neves, A., Neves, F. S., Novais, S., Oki, Y., Oliveira, E., Oliveira, R. S., Pivari, M. O., Pontes Junior, E., Ranieri, B. D., Ribas, R., Scariot, A., Schaefer, C. E., Sena, L., da Silva, P. G., Siqueira, P. R., Soares, N. C., Soares-Filho, B., Solar, R., Tabarelli, M., Vasconcellos, R., Vilela, E., Silveira, F. O. 2020; 18 (4): 213–22
  • Are protected populations of two globular cactus species facing a demographic explosion or just a "bonanza" year? JOURNAL OF ARID ENVIRONMENTS Antonini, Y., Dirzo, R., Quitete-Portela, R. 2020; 179
  • Early plant development depends on embryo damage location: the role of seed size in partial seed predation OIKOS Perea, R., Fernandes, G., Dirzo, R. 2020; 129 (3): 320–30

    View details for DOI 10.1111/oik.06912

    View details for Web of Science ID 000517172500003

  • A field experiment to determine the effect of dry-season irrigation on vegetative and reproductive traits in the wet-deciduous tree Bonellia nervosa JOURNAL OF TROPICAL ECOLOGY Sanchez, O., Quesada, M., Dirzo, R., Schlichting, C. D. 2020; 36 (1): 29–35
  • Distinct responses of antagonistic and mutualistic networks to agricultural intensification. Ecology Morrison, B. M., Dirzo, R. n. 2020: e03116


    Species interaction networks, which govern the maintenance of biodiversity and ecosystem processes within ecological communities, are being rapidly altered by anthropogenic activities worldwide. Studies on the response of species interaction networks to anthropogenic disturbance have almost exclusively focused on one interaction type at a time, such as mutualistic or antagonistic interactions, making it challenging to decipher how networks of different interaction types respond to the same anthropogenic disturbance. Moreover, few studies have simultaneously focused on the two main components of network structure: network topology (i.e. architecture) and network ecology (i.e. species identities and interaction turnover), thereby limiting our understanding of the ecological drivers underlying changes in network topology in response to anthropogenic disturbance. Here, we used 16,400 plant-pollinator and plant-herbivore interaction observations from 16 sites along an agricultural intensification gradient to compare changes in network topology and ecology between mutualistic and antagonistic networks. We measured two aspects of network topology - nestedness and modularity - and found that while the mutualistic networks were consistently more nested than antagonistic networks and antagonistic networks were consistently more modular, the rate of change in nestedness and modularity along the gradient was comparable between the two network types. Change in network ecology, however, was distinct between mutualistic and antagonistic networks, with partner switching making a significantly larger contribution to interaction turnover in the mutualistic networks than in the antagonistic networks, while species turnover was a strong contributor to interaction turnover in the antagonistic networks. The ecological and topological changes we observed in the antagonistic and mutualistic networks have different implications for pollinator and herbivore communities in agricultural landscapes, and support the idea that pollinators are more labile in their interaction partner choice whereas herbivores form more reciprocally specialized, and therefore more vulnerable, interactions. Our results also demonstrate that studying both topological and ecological network structure can help to elucidate the effects of anthropogenic disturbance on ecological communities, with applications for conservation and restoration of species interactions and the ecosystem processes they maintain.

    View details for DOI 10.1002/ecy.3116

    View details for PubMedID 32530504

  • Agricultural intensification drives changes in hybrid network robustness by modifying network structure. Ecology letters Morrison, B. M., Brosi, B. J., Dirzo, R. 2019


    Within ecological communities, species engage in myriad interaction types, yet empirical examples of hybrid species interaction networks composed of multiple types of interactions are still scarce. A key knowledge gap is understanding how the structure and stability of such hybrid networks are affected by anthropogenic disturbance. Using 15,169 interaction observations, we constructed 16 hybrid herbivore-plant-pollinator networks along an agricultural intensification gradient to explore changes in network structure and robustness to local extinctions. We found that agricultural intensification led to declines in modularity but increases in nestedness and connectance. Notably, network connectance, a structural feature typically thought to increase robustness, caused declines in hybrid network robustness, but the directionality of changes in robustness along the gradient depended on the order of local species extinctions. Our results not only demonstrate the impacts of anthropogenic disturbance on hybrid network structure, but they also provide unexpected insights into the structure-stability relationship of hybrid networks.

    View details for DOI 10.1111/ele.13440

    View details for PubMedID 31814265

  • Spatio-temporal variation of biotic and abiotic stress agents determines seedling survival in assisted oak regeneration JOURNAL OF APPLIED ECOLOGY Lopez-Sanchez, A., Pelaez, M., Dirzo, R., Fernandes, G., Seminatore, M., Perea, R. 2019
  • Peláez M, Dirzo R, Fernandes GW, Perea R. 2019. Nurse plant size and biotic stress determine quantity and quality of plant facilitation in oak savannas. Forest Ecology and Management 437: 435-442 Forest Ecology and Management Dirzo, R. 2019
  • López Gutierrez, B., Almeyda Zambrano, A., Almeyda Zambrano, S. Quispe Gil, C.A., Avellan-Arias, E., Mulder, G., Ols, C. Dirzo, R., DeLuycker, A.M., Bohlman, S., Lewis, K., Broadbent, E.N. 2019. An island of wildlife in a human-dimionated landscape on the Osa Peninsula’s Golfo Dulce coastline, Costa Rica. PLoS One. 14(3): e0214390. pone.0214390 PLoS One Dirzo, R. 2019
  • Opening the silvicultural toolbox: A new framework for conserving biodiversity in Chilean timber plantations FOREST ECOLOGY AND MANAGEMENT McFadden, T. N., Dirzo, R. 2018; 425: 75–84
  • Invasive rat eradication strongly impacts plant recruitment on a tropical atoll PLOS ONE Wolf, C. A., Young, H. S., Zilliacus, K. M., Wegmann, A. S., McKown, M., Holmes, N. D., Tershy, B. R., Dirzo, R., Kropidlowski, S., Croll, D. A. 2018; 13 (7): e0200743


    Rat eradication has become a common conservation intervention in island ecosystems and its effectiveness in protecting native vertebrates is increasingly well documented. Yet, the impacts of rat eradication on plant communities remain poorly understood. Here we compare native and non-native tree and palm seedling abundance before and after eradication of invasive rats (Rattus rattus) from Palmyra Atoll, Line Islands, Central Pacific Ocean. Overall, seedling recruitment increased for five of the six native trees species examined. While pre-eradication monitoring found no seedlings of Pisonia grandis, a dominant tree species that is important throughout the Pacific region, post-eradication monitoring documented a notable recruitment event immediately following eradication, with up to 688 individual P. grandis seedlings per 100m2 recorded one month post-eradication. Two other locally rare native trees with no observed recruitment in pre-eradication surveys had recruitment post-rat eradication. However, we also found, by five years post-eradication, a 13-fold increase in recruitment of the naturalized and range-expanding coconut palm Cocos nucifera. Our results emphasize the strong effects that a rat eradication can have on tree recruitment with expected long-term effects on canopy composition. Rat eradication released non-native C. nucifera, likely with long-term implications for community composition, potentially necessitating future management interventions. Eradication, nevertheless, greatly benefitted recruitment of native tree species. If this pattern persists over time, we expect long-term benefits for flora and fauna dependent on these native species.

    View details for PubMedID 30016347

  • Assessing sustainability in North America's ecosystems using criticality and information theory PLOS ONE Ramirez-Carrillo, E., Lopez-Corona, O., Toledo-Roy, J. C., Lovett, J. C., de Leon-Gonzalez, F., Osorio-Olvera, L., Equihua, J., Robredo, E., Frank, A., Dirzo, R., Perez-Cirera, V. 2018; 13 (7): e0200382


    Sustainability is a key concept in economic and policy debates. Nevertheless, it is usually treated only in a qualitative way and has eluded quantitative analysis. Here, we propose a sustainability index based on the premise that sustainable systems do not lose or gain Fisher Information over time. We test this approach using time series data from the AmeriFlux network that measures ecosystem respiration, water and energy fluxes in order to elucidate two key sustainability features: ecosystem health and stability. A novel definition of ecosystem health is developed based on the concept of criticality, which implies that if a system's fluctuations are scale invariant then the system is in a balance between robustness and adaptability. We define ecosystem stability by taking an information theory approach that measures its entropy and Fisher information. Analysis of the Ameriflux consortium big data set of ecosystem respiration time series is contrasted with land condition data. In general we find a good agreement between the sustainability index and land condition data. However, we acknowledge that the results are a preliminary test of the approach and further verification will require a multi-signal analysis. For example, high values of the sustainability index for some croplands are counter-intuitive and we interpret these results as ecosystems maintained in artificial health due to continuous human-induced inflows of matter and energy in the form of soil nutrients and control of competition, pests and disease.

    View details for PubMedID 30011317

  • Community composition and diversity of Neotropical root-associated fungi in common and rare trees BIOTROPICA Schroeder, J. W., Martin, J. T., Angulo, D. F., Barbosa, J. M., Perea, R., Arias-Del Razo, I., Sebastian-Gonzalez, E., Dirzo, R. 2018; 50 (4): 694–703

    View details for DOI 10.1111/btp.12553

    View details for Web of Science ID 000437264200017

  • Embryo size as a tolerance trait against seed predation: Contribution of embryo-damaged seeds to plant regeneration PERSPECTIVES IN PLANT ECOLOGY EVOLUTION AND SYSTEMATICS Perea, R., Fernandes, G., Dirzo, R. 2018; 31: 7–16
  • Cumulative effects of transgenerational induction on plant palatability to generalist and specialist herbivores WEB ECOLOGY Neylan, I. P., Dirzo, R., Sobral, M. 2018; 18 (1): 41–46
  • Anthropogenic food subsidies change the pattern of red fox diet and occurrence across Trans-Himalayas, India JOURNAL OF ARID ENVIRONMENTS Reshamwala, H. S., Shrotriya, S., Bora, B., Lyngdoh, S., Dirzo, R., Habib, B. 2018; 150: 15–20
  • Changes in livestock footprint and tree layer coverage in Mediterranean dehesas: a six-decade study based on remote sensing INTERNATIONAL JOURNAL OF REMOTE SENSING Lopez-Sanchez, A., Dirzo, R., Roig, S. 2018; 39 (14): 4727–43
  • Interacting effects of land use and climate on rodent-borne pathogens in central Kenya PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES Young, H. S., McCauley, D. J., Dirzo, R., Nunn, C. L., Campana, M. G., Agwanda, B., Otarola-Castillo, E. R., Castillo, E. R., Pringle, R. M., Veblen, K. E., Salkeld, D. J., Stewardson, K., Fleischer, R., Lambin, E. F., Palmer, T. M., Helgen, K. M. 2017; 372 (1722)


    Understanding the effects of anthropogenic disturbance on zoonotic disease risk is both a critical conservation objective and a public health priority. Here, we evaluate the effects of multiple forms of anthropogenic disturbance across a precipitation gradient on the abundance of pathogen-infected small mammal hosts in a multi-host, multi-pathogen system in central Kenya. Our results suggest that conversion to cropland and wildlife loss alone drive systematic increases in rodent-borne pathogen prevalence, but that pastoral conversion has no such systematic effects. The effects are most likely explained both by changes in total small mammal abundance, and by changes in relative abundance of a few high-competence species, although changes in vector assemblages may also be involved. Several pathogens responded to interactions between disturbance type and climatic conditions, suggesting the potential for synergistic effects of anthropogenic disturbance and climate change on the distribution of disease risk. Overall, these results indicate that conservation can be an effective tool for reducing abundance of rodent-borne pathogens in some contexts (e.g. wildlife loss alone); however, given the strong variation in effects across disturbance types, pathogen taxa and environmental conditions, the use of conservation as public health interventions will need to be carefully tailored to specific pathogens and human contexts.This article is part of the themed issue 'Conservation, biodiversity and infectious disease: scientific evidence and policy implications'.

    View details for DOI 10.1098/rstb.2016.0116

    View details for Web of Science ID 000399956400001

    View details for PubMedID 28438909

  • Cascading community and ecosystem consequences of introduced coconut palms (Cocos nucifera) in tropical islands CANADIAN JOURNAL OF ZOOLOGY Young, H. S., Miller-ter Kuile, A., McCauley, D. J., Dirzo, R. 2017; 95 (3): 139-148
  • Merging paleobiology with conservation biology to guide the future of terrestrial ecosystems SCIENCE Barnosky, A. D., Hadly, E. A., Gonzalez, P., Head, J., Polly, P. D., Lawing, A. M., Eronen, J. T., Ackerly, D. D., Alex, K., Biber, E., Blois, J., Brashares, J., Ceballos, G., Davis, E., Dietl, G. P., Dirzo, R., Doremus, H., Fortelius, M., Greene, H. W., Hellmann, J., Hickler, T., Jackson, S. T., Kemp, M., Koch, P. L., Kremen, C., Lindsey, E. L., Looy, C., Marshall, C. R., Mendenhall, C., Mulch, A., Mychajliw, A. M., Nowak, C., Ramakrishnan, U., Schnitzler, J., Das Shrestha, K., Solari, K., Stegner, L., Stegner, M. A., Stenseth, N. C., Wake, M. H., Zhang, Z. 2017; 355 (6325): 594-?


    Conservation of species and ecosystems is increasingly difficult because anthropogenic impacts are pervasive and accelerating. Under this rapid global change, maximizing conservation success requires a paradigm shift from maintaining ecosystems in idealized past states toward facilitating their adaptive and functional capacities, even as species ebb and flow individually. Developing effective strategies under this new paradigm will require deeper understanding of the long-term dynamics that govern ecosystem persistence and reconciliation of conflicts among approaches to conserving historical versus novel ecosystems. Integrating emerging information from conservation biology, paleobiology, and the Earth sciences is an important step forward on the path to success. Maintaining nature in all its aspects will also entail immediately addressing the overarching threats of growing human population, overconsumption, pollution, and climate change.

    View details for DOI 10.1126/science.aah4787

    View details for PubMedID 28183912

  • Saving the World's Terrestrial Megafauna BIOSCIENCE Ripple, W. J., Chapron, G., Vicente Lopez-Bao, J., Durant, S. M., Macdonald, D. W., Lindsey, P. A., Bennett, E. L., Beschta, R. L., Bruskotter, J. T., Campos-Arceiz, A., Corlett, R. T., Darimont, C. T., Dickman, A. J., Dirzo, R., Dublin, H. T., Estes, J. A., Everatt, K. T., Galetti, M., Goswami, V. R., Hayward, M. W., Hedges, S., Hoffmann, M., Hunter, L. T., Kerley, G. I., Letnic, M., Levi, T., Maisels, F., Morrison, J. C., Nelson, M. P., Newsome, T. M., Painter, L., Pringle, R. M., Sandom, C. J., Terborgh, J., Treves, A., Van Valkenburgh, B., Vucetich, J. A., Wirsing, A. J., Wallach, A. D., Wolf, C., Woodroffe, R., Young, H., Zhang, L. 2016; 66 (10): 807-812
  • Bushmeat hunting and extinction risk to the world's mammals ROYAL SOCIETY OPEN SCIENCE Ripple, W. J., Abernethy, K., Betts, M. G., Chapron, G., Dirzo, R., Galetti, M., Levi, T., Lindsey, P. A., Macdonald, D., Machovina, B., Newsome, T. M., Peres, C. A., Wallach, A. D., Wolf, C., Young, H. 2016; 3 (10)


    Terrestrial mammals are experiencing a massive collapse in their population sizes and geographical ranges around the world, but many of the drivers, patterns and consequences of this decline remain poorly understood. Here we provide an analysis showing that bushmeat hunting for mostly food and medicinal products is driving a global crisis whereby 301 terrestrial mammal species are threatened with extinction. Nearly all of these threatened species occur in developing countries where major coexisting threats include deforestation, agricultural expansion, human encroachment and competition with livestock. The unrelenting decline of mammals suggests many vital ecological and socio-economic services that these species provide will be lost, potentially changing ecosystems irrevocably. We discuss options and current obstacles to achieving effective conservation, alongside consequences of failure to stem such anthropogenic mammalian extirpation. We propose a multi-pronged conservation strategy to help save threatened mammals from immediate extinction and avoid a collapse of food security for hundreds of millions of people.

    View details for DOI 10.1098/rsos.160498

    View details for Web of Science ID 000389241700035

    View details for PubMedID 27853564

    View details for PubMedCentralID PMC5098989

  • Post-dispersal seed recovery by animals: is it a plant- or an animal-driven process? OIKOS Perea, R., Dirzo, R., San Miguel, A., Gil, L. 2016; 125 (8): 1203-1210

    View details for DOI 10.1111/oik.02556

    View details for Web of Science ID 000381207200015

  • Does tropical forest fragmentation affect plant anti-herbivore defensive and nutritional traits? JOURNAL OF TROPICAL ECOLOGY Ruiz-Guerra, B., Guevara, R., Velazquez-Rosas, N., Dirzo, R. 2016; 32: 162-164
  • Does tropical forest fragmentation affect plant anti-herbivore defensive and nutritional traits? Journal of Tropical Ecology Ruiz-Guerra, B., Guevara, R., Velazquez-Rosas, N., Dirzo, R. 2016; 32: 162-164
  • Patterns, Causes, and Consequences of Anthropocene Defaunation ANNUAL REVIEW OF ECOLOGY, EVOLUTION, AND SYSTEMATICS, VOL 47 Young, H. S., McCauley, D. J., Galetti, M., Dirzo, R. 2016; 47: 333-358
  • Genetics-based interactions among plants, pathogens, and herbivores define arthropod community structure ECOLOGY Busby, P. E., Lamit, L. J., Keith, A. R., Newcombe, G., Gehring, C. A., Whitham, T. G., Dirzo, R. 2015; 96 (7): 1974-1984

    View details for DOI 10.1890/13-2031.1

    View details for Web of Science ID 000357525800024

  • Genetics-based interactions among plants, pathogens, and herbivores define arthropod community structure. Ecology Busby, P. E., Lamit, L. J., Keith, A. R., Newcombe, G., Gehring, C. A., Whitham, T. G., Dirzo, R. 2015; 96 (7): 1974-1984


    Plant resistance to pathogens or insect herbivores is common, but its potential for indirectly influencing plant-associated communities is poorly known. Here, we test whether pathogens' indirect effects on arthropod communities and herbivory depend on plant resistance to pathogens and/or herbivores, and address the overarching interacting foundation species hypothesis that genetics-based interactions among a few highly interactive species can structure a much larger community. In a manipulative field experiment using replicated genotypes of two Populus species and their interspecific hybrids, we found that genetic variation in plant resistance to both pathogens and insect herbivores modulated the strength of pathogens' indirect effects on arthropod communities and insect herbivory. First, due in part to the pathogens' differential impacts on leaf biomass among the two Populus species and the hybrids, the pathogen most strongly impacted arthropod community composition, richness, and abundance on the pathogen-susceptible tree species. Second, we found similar patterns comparing pathogen-susceptible and pathogen-resistant genotypes within species. Third, within a plant species, pathogens caused a fivefold greater reduction in herbivory on insect-herbivore-susceptible plant genotypes than on herbivore-resistant genotypes, demonstrating that the pathogen-herbivore interaction is genotype dependent. We conclude that interactions among plants, pathogens, and herbivores can structure multitrophic communities, supporting the interacting foundation species hypothesis. Because these interactions are genetically based, evolutionary changes in genetic resistance could result in ecological changes in associated communities, which may in turn feed back to affect plant fitness.

    View details for PubMedID 26378319

  • Drivers of Intensity and Prevalence of Flea Parasitism on Small Mammals in East African Savanna Ecosystems. journal of parasitology Young, H. S., Dirzo, R., McCauley, D. J., Agwanda, B., Cattaneo, L., Dittmar, K., Eckerlin, R. P., Fleischer, R. C., Helgen, L. E., Hintz, A., Montinieri, J., Zhao, S., Helgen, K. M. 2015; 101 (3): 327-335


    The relative importance of environmental factors and host factors in explaining variation in prevalence and intensity of flea parasitism in small mammal communities is poorly established. We examined these relationships in an East African savanna landscape, considering multiple host levels: across individuals within a local population, across populations within species, and across species within a landscape. We sampled fleas from 2,672 small mammals of 27 species. This included a total of 8,283 fleas, with 5 genera and 12 species identified. Across individual hosts within a site, both rodent body mass and season affected total intensity of flea infestation, although the explanatory power of these factors was generally modest (<10%). Across host populations in the landscape, we found consistently positive effects of host density and negative effects of vegetation cover on the intensity of flea infestation. Other factors explored (host diversity, annual rainfall, anthropogenic disturbance, and soil properties) tended to have lower and less consistent explanatory power. Across host species in the landscape, we found that host body mass was strongly positively correlated with both prevalence and intensity of flea parasitism, while average robustness of a host species to disturbance was not correlated with flea parasitism. Cumulatively, these results provide insight into the intricate roles of both host and environmental factors in explaining complex patterns of flea parasitism across landscape mosaics.

    View details for DOI 10.1645/14-684.1

    View details for PubMedID 25634599

  • DRIVERS OF INTENSITY AND PREVALENCE OF FLEA PARASITISM ON SMALL MAMMALS IN EAST AFRICAN SAVANNA ECOSYSTEMS JOURNAL OF PARASITOLOGY Young, H. S., Dirzo, R., McCauley, D. J., Agwanda, B., Cattaneo, L., Dittmarjj, K., Eckerlin, R. P., Fleischer, R. C., Helgen, L. E., Hintz, A., Montinieri, J., Zhao, S., Helgen, K. M. 2015; 101 (3): 327-335

    View details for DOI 10.1645/14-684.1

    View details for Web of Science ID 000356539600009

  • Collapse of the world's largest herbivores. Science advances Ripple, W. J., Newsome, T. M., Wolf, C., Dirzo, R., Everatt, K. T., Galetti, M., Hayward, M. W., Kerley, G. I., Levi, T., Lindsey, P. A., Macdonald, D. W., Malhi, Y., Painter, L. E., Sandom, C. J., Terborgh, J., Van Valkenburgh, B. 2015; 1 (4)


    Large wild herbivores are crucial to ecosystems and human societies. We highlight the 74 largest terrestrial herbivore species on Earth (body mass ≥100 kg), the threats they face, their important and often overlooked ecosystem effects, and the conservation efforts needed to save them and their predators from extinction. Large herbivores are generally facing dramatic population declines and range contractions, such that ~60% are threatened with extinction. Nearly all threatened species are in developing countries, where major threats include hunting, land-use change, and resource depression by livestock. Loss of large herbivores can have cascading effects on other species including large carnivores, scavengers, mesoherbivores, small mammals, and ecological processes involving vegetation, hydrology, nutrient cycling, and fire regimes. The rate of large herbivore decline suggests that ever-larger swaths of the world will soon lack many of the vital ecological services these animals provide, resulting in enormous ecological and social costs.

    View details for DOI 10.1126/sciadv.1400103

    View details for PubMedID 26601172

    View details for PubMedCentralID PMC4640652

  • Effects of Land Use on Plague (Yersinia pestis) Activity in Rodents in Tanzania AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE McCauley, D. J., Salkeld, D. J., Young, H. S., Makundi, R., Dirzo, R., Eckerlin, R. P., Lambin, E. F., Gaffikin, L., Barry, M., Helgen, K. M. 2015; 92 (4): 776-783


    Understanding the effects of land-use change on zoonotic disease risk is a pressing global health concern. Here, we compare prevalence of Yersinia pestis, the etiologic agent of plague, in rodents across two land-use types-agricultural and conserved-in northern Tanzania. Estimated abundance of seropositive rodents nearly doubled in agricultural sites compared with conserved sites. This relationship between land-use type and abundance of seropositive rodents is likely mediated by changes in rodent and flea community composition, particularly via an increase in the abundance of the commensal species, Mastomys natalensis, in agricultural habitats. There was mixed support for rodent species diversity negatively impacting Y. pestis seroprevalence. Together, these results suggest that land-use change could affect the risk of local transmission of plague, and raise critical questions about transmission dynamics at the interface of conserved and agricultural habitats. These findings emphasize the importance of understanding disease ecology in the context of rapidly proceeding landscape change.

    View details for DOI 10.4269/ajtmh.14-0504

    View details for Web of Science ID 000352828200018

    View details for PubMedID 25711606

    View details for PubMedCentralID PMC4385772

  • Context-dependent effects of large-wildlife declines on small-mammal communities in central Kenya. Ecological applications Young, H. S., McCauley, D. J., Dirzo, R., Goheen, J. R., Agwanda, B., Brook, C., Otarola-Castillo, E., Ferguson, A. W., Kinyua, S. N., McDonough, M. M., Palmer, T. M., Pringle, R. M., Young, T. P., Helgen, K. M. 2015; 25 (2): 348-360


    Many species of large wildlife have declined drastically worldwide. These reductions often lead to profound shifts in the ecology of entire communities and ecosystems. However, the effects of these large-wildlife declines on other taxa likely hinge upon both underlying abiotic properties of these systems and on the types of secondary anthropogenic changes associated with wildlife loss, making impacts difficult to predict. To better understand how these important contextual factors determine the consequences of large-wildlife declines on other animals in a community, we examined the effects of three common forms of large-wildlife loss (removal without replacement [using fences], removal followed by replacement with domestic stock, and removal accompanied by crop agricultural use) on small-mammal abundance, diversity, and community composition, in landscapes that varied in several abiotic attributes (rainfall, soil fertility, land-use intensity) in central Kenya. We found that small-mammal communities were indeed heavily impacted by all forms of large-wildlife decline, showing, on average: (1) higher densities, (2) lower species richness per site, and (3) different species assemblages in sites from which large wildlife were removed. However, the nature and magnitude of these effects were strongly context dependent. Rainfall, type of land-use change, and the interaction of these two factors were key predictors of both the magnitude and type of responses of small mammals. The strongest effects, particularly abundance responses, tended to be observed in low-rainfall areas. Whereas isolated wildlife removal primarily led to increased small-mammal abundance, wildlife removal associated with secondary uses (agriculture, domestic stock) had much more variable effects on abundance and stronger impacts on diversity and composition. Collectively, these results (1) highlight the importance of context in determining the impacts of large-wildlife decline on small-mammal communities, (2) emphasize the challenges in extrapolating results from controlled experimental studies to predict the effects of wildlife declines that are accompanied by secondary land-uses, and (3) suggest that, because of the context-dependent nature of the responses to large-wildlife decline, large-wildlife status alone cannot be reliably used to predict small-mammal community changes.

    View details for PubMedID 26263659

  • Experimental defaunation of terrestrial mammalian herbivores alters tropical rainforest understorey diversity. Proceedings. Biological sciences / The Royal Society Camargo-Sanabria, A. A., Mendoza, E., Guevara, R., Martínez-Ramos, M., Dirzo, R. 2015; 282 (1800)


    It has been suggested that tropical defaunation may unleash community-wide cascading effects, leading to reductions in plant diversity. However, experimental evidence establishing cause-effect relationships thereof is poor. Through a 5 year exclosure experiment, we tested the hypothesis that mammalian defaunation affects tree seedling/sapling community dynamics leading to reductions in understorey plant diversity. We established plot triplets (n = 25) representing three defaunation contexts: terrestrial-mammal exclosure (TE), medium/large mammal exclosure (PE) and open access controls (C). Seedlings/saplings 30-100 cm tall were marked and identified within each of these plots and re-censused three times to record survival and recruitment. In the periods 2010-2011 and 2011-2013, survival was greater in PE than in C plots and recruitment was higher in TE plots than in C plots. Overall, seedling density increased by 61% in TE plots and 23% in PE plots, whereas it decreased by 5% in C plots. Common species highly consumed by mammals (e.g. Brosimum alicastrum and Ampelocera hottlei) increased in their abundance in TE plots. Rarefaction curves showed that species diversity decreased in TE plots from 2008 to 2013, whereas it remained similar for C plots. Given the prevalence of tropical defaunation, we posit this is an anthropogenic effect threatening the maintenance of tropical forest diversity.

    View details for DOI 10.1098/rspb.2014.2580

    View details for PubMedID 25540281

    View details for PubMedCentralID PMC4298212

  • Strategic Actions to Value, Conserve, and Restore the Natural Capital of Megadiversity Countries: The Case of Mexico BIOSCIENCE Sarukhan, J., Urquiza-Haas, T., Koleff, P., Carabias, J., Dirzo, R., Ezcurra, E., Cerdeira-Estrada, S., Soberon, J. 2015; 65 (2): 164-173
  • Integrating Stand and Soil Properties to Understand Foliar Nutrient Dynamics during Forest Succession Following Slash-and-Burn Agriculture in the Bolivian Amazon. PloS one Broadbent, E. N., Almeyda Zambrano, A. M., Asner, G. P., Soriano, M., Field, C. B., de Souza, H. R., Peña-Claros, M., Adams, R. I., Dirzo, R., Giles, L. 2014; 9 (2)

    View details for DOI 10.1371/journal.pone.0086042

    View details for PubMedID 24516525

  • Effects of cattle management on oak regeneration in northern californian mediterranean oak woodlands. PloS one López-Sánchez, A., Schroeder, J., Roig, S., Sobral, M., Dirzo, R. 2014; 9 (8)


    Oak woodlands of Mediterranean ecosystems, a major component of biodiversity hotspots in Europe and North America, have undergone significant land-use change in recent centuries, including an increase in grazing intensity due to the widespread presence of cattle. Simultaneously, a decrease in oak regeneration has been observed, suggesting a link between cattle grazing intensity and limited oak regeneration. In this study we examined the effect of cattle grazing on coast live oak (Quercus agrifolia Née) regeneration in San Francisco Bay Area, California. We studied seedling, sapling and adult density of coast live oak as well as vertebrate herbivory at 8 independent sites under two grazing conditions: with cattle and wildlife presence (n = 4) and only with wildlife (n = 4). The specific questions we addressed are: i) to what extent cattle management practices affect oak density, and ii) what is the effect of rangeland management on herbivory and size of young oak plants. In areas with cattle present, we found a 50% reduction in young oak density, and plant size was smaller, suggesting that survival and growth young plants in those areas are significantly limited. In addition, the presence of cattle raised the probability and intensity of herbivory (a 1.5 and 1.8-fold difference, respectively). These results strongly suggest that the presence of cattle significantly reduced the success of young Q. agrifolia through elevated herbivory. Given the potential impact of reduced recruitment on adult populations, modifying rangeland management practices to reduce cattle grazing pressure seems to be an important intervention to maintain Mediterranean oak woodlands.

    View details for DOI 10.1371/journal.pone.0105472

    View details for PubMedID 25126939

    View details for PubMedCentralID PMC4134313

  • The evolution of ecology in Mexico: facing challenges and preparing for the future FRONTIERS IN ECOLOGY AND THE ENVIRONMENT Martinez, M. L., Manson, R. H., Balvanera, P., Dirzo, R., Soberon, J., Garcia-Barrios, L., Martinez-Ramos, M., Moreno-Casasola, P., Rosenzweig, L., Sarukhan, J. 2006; 4 (5): 259-267
  • An endangered oasis of aquatic microbial biodiversity in the Chihuahuan desert PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Souza, V., Espinosa-Asuar, L., Escalante, A. E., Eguiarte, L. E., Farmer, J., Forney, L., Lloret, L., Rodriguez-Martinez, J. M., Soberon, X., Dirzo, R., Elser, J. J. 2006; 103 (17): 6565-6570


    The Cuatro Cienegas basin in the Chihuahuan desert is a system of springs, streams, and pools. These ecosystems support >70 endemic species and abundant living stromatolites and other microbial communities, representing a desert oasis of high biodiversity. Here, we combine data from molecular microbiology and geology to document the microbial biodiversity of this unique environment. Ten water samples from locations within the Cuatro Cienegas basin and two neighboring valleys as well as three samples of wet sediments were analyzed. The phylogeny of prokaryotic populations in the samples was determined by characterizing cultured organisms and by PCR amplification and sequencing of 16S rRNA genes from total community DNA. The composition of microbial communities was also assessed by determining profiles of terminal restriction site polymorphisms of 16S rRNA genes in total community DNA. There were 250 different phylotypes among the 350 cultivated strains. Ninety-eight partial 16S rRNA gene sequences were obtained and classified. The clones represented 38 unique phylotypes from ten major lineages of Bacteria and one of Archaea. Unexpectedly, 50% of the phylotypes were most closely related to marine taxa, even though these environments have not been in contact with the ocean for tens of millions of years. Furthermore, terminal restriction site polymorphism profiles and geological data suggest that the aquatic ecosystems of Cuatro Cienegas are hydrologically interconnected with adjacent valleys recently targeted for agricultural intensification. The findings underscore the conservation value of desert aquatic ecosystems and the urgent need for study and preservation of freshwater microbial communities.

    View details for DOI 10.1073/pnas.0601434103

    View details for Web of Science ID 000237151000028

    View details for PubMedID 16618921

  • Global state of biodiversity and loss ANNUAL REVIEW OF ENVIRONMENT AND RESOURCES Dirzo, R., Raven, P. H. 2003; 28: 137-167
  • Genetic divergence among Mexican populations of red mangrove (Rhizophora mangle): geographic and historic effects EVOLUTIONARY ECOLOGY RESEARCH Nunez-Farfan, J., DOMINGUEZ, C. A., Eguiarte, L. E., Cornejo, A., Quijano, M., Vargas, J., Dirzo, R. 2002; 4 (7): 1049-1064
  • Consumption of macro-fungi by invertebrates in a Mexican tropical cloud forest: do fruit body characteristics matter? JOURNAL OF TROPICAL ECOLOGY Guevara, R., Dirzo, R. 1999; 15: 603-617
  • Flower morphometry of Rhizophora mangle (Rhizophoraceae): Geographical variation in Mexican populations AMERICAN JOURNAL OF BOTANY DOMINGUEZ, C. A., Eguiarte, L. E., Nunez-Farfan, J., Dirzo, R. 1998; 85 (5): 637-643


    We explored the patterns of intra- and interpopulation variation in flower morphology of the red mangrove, Rhizophora mangle. Twelve populations in Mexico were studied: five from the Gulf of Mexico and the Caribbean Sea, and seven from the Pacific Coast. Six metric floral attributes were measured from a sample of 1370 flowers. Significant differences among populations were found for all six attributes. Because floral attributes were all correlated, scores derived from principal factor analysis were used to describe the variation in flower morphology. Two factors explained essentially all of the variance in flower morphology. Corolla and calyx size had a strong effect on factor 1, while gynoecium size had the higher effect on factor 2. Nested analyses of variance on the scores from both factors revealed significant differences among coasts, among populations within coasts, and among plants within populations. Nonetheless, this variation cannot be explained as a result of clinal variation, as indicated by a series of regression analyses. Cluster analysis (UPGMA) showed that a population from the Pacific coast was clustered together with those of the Atlantic, and the arrangement of populations within each coast showed no evident geographical pattern. We propose that frequent events of extinction and recolonization by a few individuals, followed by selfing, may produce differentiation among populations of red mangrove.

    View details for Web of Science ID 000073708300004

    View details for PubMedID 21715293

  • A rapid method for the assessment of the macromycota. The fungal community of an evergreen cloud forest as an example CANADIAN JOURNAL OF BOTANY-REVUE CANADIENNE DE BOTANIQUE Guevara, R., Dirzo, R. 1998; 76 (4): 596-601
  • Mating system consequences on resistance to herbivory and life history traits in Datura stramonium AMERICAN JOURNAL OF BOTANY NUNEZFARFAN, J., CabralesVargas, R. A., Dirzo, R. 1996; 83 (8): 1041-1049
  • The role of an avian nectar robber and of Hummingbird pollinators in the reproduction of two plant species FUNCTIONAL ECOLOGY Arizmendi, M. C., DOMINGUEZ, C. A., Dirzo, R. 1996; 10 (1): 119-127