Program Affiliations

  • Center for Latin American Studies

Current Research and Scholarly Interests

Land use, biodiversity dynamics, ecosystem services

Stanford Advisees

Graduate and Fellowship Programs

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

All Publications

  • The payoff of conservation investments in tropical countryside PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Chan, K. M., Daily, G. C. 2008; 105 (49): 19342-19347


    The future of biodiversity and ecosystem services hinges on harmonizing agricultural production and conservation, yet there is no planning algorithm for predicting the efficacy of conservation investments in farmland. We present a conservation planning framework for countryside (working agricultural landscapes) that calculates the production and conservation benefits to the current baseline of incremental investments. Our framework is analogous to the use of reserve design algorithms. Unlike much countryside modeling, our framework is designed for application in data-limited contexts, which are prevalent. We apply our framework to quantify the payoff for Costa Rican birds of changing farm plot and border vegetation. We show that installing windbreaks of native vegetation enhances both bird diversity and farm income, especially when complementing certain crop types. We make predictions that differ from those of approaches currently applied to agri-environment planning,: e.g., although habitat with trees has lower local species richness than farm plot habitats (1-44% lower), replacing any plot habitat with trees should boost regional richness considerably. Our planning framework reveals the small, targeted changes on farms that can make big differences for biodiversity.

    View details for DOI 10.1073/pnas.0810522105

    View details for Web of Science ID 000261706600058

    View details for PubMedID 19036931

  • Sustaining biodiversity in ancient tropical countryside PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Ranganathan, J., Daniels, R. J., Chandran, M. D., Ehrlich, P. R., Daily, G. C. 2008; 105 (46): 17852-17854


    With intensifying demands for food and biofuels, a critical threat to biodiversity is agricultural expansion into native tropical ecosystems. Tropical agriculture, particularly intensive agriculture, often supports few native organisms, and consequently has been largely overlooked in conservation planning; yet, recent work in the Neotropics demonstrates that tropical agriculture with certain features can support significant biodiversity, decades after conversion to farmland. It remains unknown whether this conservation value can be sustained for centuries to millennia. Here, we quantify the bird diversity affiliated with agricultural systems in southwest India, a region continuously cultivated for >2,000 years. We show that arecanut palm (Areca catechu) production systems retain 90% of the bird species associated with regional native forest. Two factors promote this high conservation value. First, the system involves intercropping with multiple, usually woody, understory species and, thus, has high vertical structural complexity that is positively correlated with bird species richness. Second, the system encompasses nearby forests, where large quantities of leaf litter are extracted for mulch. The preservation of these forests on productive land traces back to their value in supplying inputs to arecanut cultivation. The long-term biodiversity value of an agricultural ecosystem has not been documented in South and Southeast Asia. Our findings open a new conservation opportunity for this imperiled region that may well extend to other crops. Some of these working lands may be able to sustain native species over long-time scales, indicating that conservation investments in agriculture today could pay off for people and for nature.

    View details for DOI 10.1073/pnas.0808874105

    View details for Web of Science ID 000261225600052

    View details for PubMedID 18981411

  • Ecosystem services: From theory to implementation PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Daily, G. C., Matson, P. A. 2008; 105 (28): 9455-9456


    Around the world, leaders are increasingly recognizing ecosystems as natural capital assets that supply life-support services of tremendous value. The challenge is to turn this recognition into incentives and institutions that will guide wise investments in natural capital, on a large scale. Advances are required on three key fronts, each featured here: the science of ecosystem production functions and service mapping; the design of appropriate finance, policy, and governance systems; and the art of implementing these in diverse biophysical and social contexts. Scientific understanding of ecosystem production functions is improving rapidly but remains a limiting factor in incorporating natural capital into decisions, via systems of national accounting and other mechanisms. Novel institutional structures are being established for a broad array of services and places, creating a need and opportunity for systematic assessment of their scope and limitations. Finally, it is clear that formal sharing of experience, and defining of priorities for future work, could greatly accelerate the rate of innovation and uptake of new approaches.

    View details for DOI 10.1073/pnas.0804960105

    View details for Web of Science ID 000257784700003

    View details for PubMedID 18621697

  • Field evidence that ecosystem service projects support biodiversity and diversify options PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Goldman, R. L., Tallis, H., Kareiva, P., Daily, G. C. 2008; 105 (27): 9445-9448


    Ecosystem service approaches to conservation are being championed as a new strategy for conservation, under the hypothesis that they will broaden and deepen support for biodiversity protection. Where traditional approaches focus on setting aside land by purchasing property rights, ecosystem service approaches aim to engage a much wider range of places, people, policies, and financial resources in conservation. This is particularly important given projected intensification of human impacts, with rapid growth in population size and individual aspirations. Here we use field research on 34 ecosystem service (ES) projects and 26 traditional biodiversity (BD) projects from the Western Hemisphere to test whether ecosystem service approaches show signs of realizing their putative potential. We find that the ES projects attract on average more than four times as much funding through greater corporate sponsorship and use of a wider variety of finance tools than BD projects. ES projects are also more likely to encompass working landscapes and the people in them. We also show that, despite previous concern, ES projects not only expand opportunities for conservation, but they are no less likely than BD projects to include or create protected areas. Moreover, they do not draw down limited financial resources for conservation but rather engage a more diverse set of funders. We also found, however, that monitoring of conservation outcomes in both cases is so infrequent that it is impossible to assess the effectiveness of either ES or BD approaches.

    View details for DOI 10.1073/pnas.0800208105

    View details for Web of Science ID 000257645400056

    View details for PubMedID 18591667

  • Inadequate assessment of the ecosystem service rationale for conservation: Reply to Ghazoul CONSERVATION BIOLOGY Kremen, C., Daily, G. C., Klein, A., Scofield, D. 2008; 22 (3): 795-798
  • Ecosystem-service science and the way forward for conservation CONSERVATION BIOLOGY Armsworth, P. R., Chan, K. M., Daily, G. C., Ehrlich, P. R., Kremen, C., Ricketts, T. H., Sanjayan, M. A. 2007; 21 (6): 1383-1384
  • Satellite detection of bird communities in tropical countryside ECOLOGICAL APPLICATIONS Ranganathan, J., Chan, K. M., Daily, G. C. 2007; 17 (5): 1499-1510


    The future of biodiversity hinges partly on realizing the potentially high conservation value of human-dominated countryside. The characteristics of the countryside that promote biodiversity preservation remain poorly understood, however, particularly at the fine scales at which individual farmers tend to make land use decisions. To address this problem, we explored the use of a rapid remote sensing method for estimating bird community composition in tropical countryside, using a two-step process. First, we asked how fine-grained variation in land cover affected community composition. Second, we determined whether the observed changes in community composition correlated with three easily accessible remote sensing metrics (wetness, greenness, and brightness), derived from performing a tasseled-cap transformation on a Landsat Enhanced Thematic Mapper Plus image. As a comparison, we also examined whether the most commonly used remote sensing indicator in ecology, the Normalized Difference Vegetation Index (NDVI), correlated with community composition. We worked within an agricultural landscape in southern Costa Rica, where the land comprised a complex and highly heterogeneous mosaic of remnant native vegetation, pasture, coffee cultivation, and other crops. In this region, we selected 12 study sites (each < 60 ha) that encompassed the range of available land cover possibilities in the countryside. Within each site, we surveyed bird communities within all major land cover types, and we conducted detailed field mapping of land cover. We found that the number of forest-affiliated species increased with forest cover and decreased with residential area across sites. Conversely, the number of agriculture-affiliated species using forest increased with land area devoted to agricultural and residential uses. Interestingly, we found that the wetness and brightness metrics predicted the number of forest- and agriculture-affiliated species within a site as well as did detailed field-generated maps of land cover. In contrast, NDVI and the closely correlated greenness metric did not correlate with land cover or with bird communities. Our study shows the strong potential of the tasseled-cap transformation as a tool for assessing the conservation value of countryside for biodiversity.

    View details for Web of Science ID 000248265700019

    View details for PubMedID 17708224

  • Persistence of forest birds in the Costa Rican agricultural countryside CONSERVATION BIOLOGY Sekercioglu, C. H., Loarie, S. R., Brenes, F. O., Ehrlich, P. R., Daily, G. C. 2007; 21 (2): 482-494


    Understanding the persistence mechanisms of tropical forest species in human-dominated landscapes is a fundamental challenge of tropical ecology and conservation. Many species, including more than half of Costa Rica's native land birds, use mostly deforested agricultural countryside, but how they do so is poorly known. Do they commute regularly to forest or can some species survive in this human-dominated landscape year-round? Using radiotelemetry, we detailed the habitat use, movement, foraging, and nesting patterns of three bird species, Catharus aurantiirostris, Tangara icterocephala, and Turdus assimilis, by obtaining 8101 locations from 156 individuals. We chose forest birds that varied in their vulnerability to deforestation and were representative of the species found both in forest and human-dominated landscapes. Our study species did not commute from extensive forest; rather, they fed and bred in the agricultural countryside. Nevertheless, T. icterocephala and T. assimilis, which are more habitat sensitive, were highly dependent on the remaining trees. Although trees constituted only 11% of land cover, these birds spent 69% to 85% of their time in them. Breeding success of C. aurntiirostris and T. icterocephala in deforested habitats was not different than in forest remnants, where T. assimilis experienced reduced breeding success. Although this suggests an ecological trap for T. assimilis, higher fledgling survival in forest remnants may make up for lower productivity. Tropical countryside has high potential conservation value, which can be enhanced with even modest increases in tree cover. Our findings have applicability to many human-dominated tropical areas that have the potential to conserve substantial biodiversity if appropriate restoration measures are taken.

    View details for DOI 10.1111/j.1523-1739.2007.00655.x

    View details for Web of Science ID 000245438200024

    View details for PubMedID 17391198

  • Bee community shifts with landscape context in a tropical countryside ECOLOGICAL APPLICATIONS Brosi, B. J., Daily, G. C., Ehrlich, P. R. 2007; 17 (2): 418-430


    The ongoing scientific controversy over a putative "global pollination crisis" underscores the lack of understanding of the response of bees (the most important taxon of pollinators) to ongoing global land-use changes. We studied the effects of distance to forest, tree management, and floral resources on bee communities in pastures (the dominant land-use type) in southern Costa Rica. Over two years, we sampled bees and floral resources in 21 pastures at three distance classes from a large (approximately 230-ha) forest patch and of three common types: open pasture; pasture with remnant trees; and pasture with live fences. We found no consistent differences in bee diversity or abundance with respect to pasture management or floral resources. Bee community composition, however, was strikingly different at forest edges as compared to deforested countryside only a few hundred meters from forest. At forest edges, native social stingless bees (Apidae: Meliponini) comprised approximately 50% of the individuals sampled, while the alien honeybee Apis mellifera made up only approximately 5%. Away from forests, meliponines dropped to approximately 20% of sampled bees, whereas Apis increased to approximately 45%. Meliponine bees were also more speciose at forest edge sites than at a distance from forest, their abundance decreased with continuous distance to the nearest forest patch, and their species richness was correlated with the proportion of forest cover surrounding sample sites at scales from 200 to 1200 m. Meliponines and Apis together comprise the eusocial bee fauna of the study area and are unique in quickly recruiting foragers to high-quality resources. The diverse assemblage of native meliponine bees covers a wide range of body sizes and flower foraging behavior not found in Apis, and populations of many bee species (including Apis), are known to fluctuate considerably from year to year. Thus, the forest-related changes in eusocial bee communities we found may have important implications for: (1) sustaining a diverse bee fauna in tropical countryside; (2) ensuring the effective pollination of a diverse native plant community; and (3) the efficiency and stability of agricultural pollination, particularly for short-time-scale, mass-flowering crops such as coffee.

    View details for Web of Science ID 000245744200011

    View details for PubMedID 17489249

  • Evaluating the potential for conservation development: Biophysical, economic, and institutional perspectives CONSERVATION BIOLOGY Pejchar, L., Morgan, P. M., Caldwell, M. R., Palmer, C., Daily, G. C. 2007; 21 (1): 69-78


    The widespread conversion of rural land to low-density residential development poses an immediate threat to biodiversity and to the provision of ecosystem services. Given that development will continue and environmental stakes are high, analyzing alternative growth strategies is critical. Conservation development is one such strategy that has the potential to benefit ecosystems and diverse stakeholders including developers, homebuyers, governments, and society as a whole. Conservation development clusters homes on one part of a property to manage the most ecologically important land for the conservation of biodiversity and ecosystem services. We draw on lessons learned from landscape ecology, open-space development, and regional planning to weigh the biophysical, economic, and institutional evidence for and against conservation development. Conservation development offers many potential environmental and economic advantages: relatively high home values and appreciation rates, lower development costs, and social and ecological benefits to society including landscape connectivity, protection and active stewardship of important ecological assets, and the maintenance of ecosystem services. But this approach also has shortcomings: it may require enlightened institutional regulations and regional planning (and/or ecologically aware developers), it is not always more profitable than conventional development and thus may require subsidies or incentives, and additional research is required to fully understand its benefits and drawbacks. With more information on the effects of clustering, the development of flexible zoning laws, and effective regional planning, conservation development could be a viable strategy for sustaining biodiversity and ecosystem services in changing landscapes.

    View details for DOI 10.1111/j.1523-1739.2006.00572.x

    View details for Web of Science ID 000244148800015

    View details for PubMedID 17298512

  • Modeling biodiversity dynamics in countryside landscapes ECOLOGY Pereira, H. M., Daily, G. C. 2006; 87 (8): 1877-1885


    The future of biodiversity hinges to a great extent on the conservation value of countryside, the growing fraction of Earth's surface heavily influenced by human activities. How many species, and which species, can persist in such landscapes (and analogous seascapes) are open questions. Here we explore two complementary theoretical frameworks to address these questions: species-area relationships and demographic models. We use the terrestrial mammal fauna of Central America to illustrate the application of both frameworks. We begin by proposing a multi-habitat species-area relationship, the countryside species-area relationship, to forecast species extinction rates. To apply it, we classify the mammal fauna by affinity to native and human-dominated habitats. We show how considering the conservation value of countryside habitats changes estimates derived from the classic species-area approach We also examine how the z value of the species-area relationship affects extinction estimates. Next, we present a framework for assessing the relative vulnerability of species to extinction in the countryside, based on the Skellam model of population dynamics. This model predicts the minimum area of contiguous native habitat required for persistence of a species, which we use as an indicator of vulnerability to habitat change. To apply the model, we use our habitat affinity classification of mammals and we estimate life-history parameters by species and habitat type. The resulting ranking of vulnerabilities is significantly correlated with the World Conservation Union (IUCN) Red List assessment.

    View details for Web of Science ID 000239833400002

    View details for PubMedID 16937624

  • Business strategies for conservation on private lands: Koa forestry as a case study PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Goldstein, J. H., Daily, G. C., Friday, J. B., Matson, P. A., Naylor, R. A. 2006; 103 (26): 10140-10145


    Innovative financial instruments are being created to reward conservation on private, working lands. Major design challenges remain, however, to make investments in biodiversity and ecosystem services economically attractive and commonplace. From a business perspective, three key financial barriers for advancing conservation land uses must frequently be addressed: high up-front costs, long time periods with no revenue, and high project risk due to long time horizons and uncertainty. We explored ways of overcoming these barriers on grazing lands in Hawaii by realizing a suite of timber and conservation revenue streams associated with their (partial) reforestation. We calculated the financial implications of alternative strategies, focusing on Acacia koa ("koa") forestry because of its high conservation and economic potential. Koa's timber value alone creates a viable investment (mean net present value = $453/acre), but its long time horizon and poor initial cash flow pose formidable challenges for landowners. At present, subsidy payments from a government conservation program targeting benefits for biodiversity, water quality, and soil erosion have the greatest potential to move landowners beyond the tipping point in favor of investments in koa forestry, particularly when combined with future timber harvest (mean net present value = $1,661/acre). Creating financial mechanisms to capture diverse ecosystem service values through time will broaden opportunities for conservation land uses. Governments, nongovernmental organizations, and private investors have roles to play in catalyzing this transition by developing new revenue streams that can reach a broad spectrum of landowners.

    View details for DOI 10.1073/pnas.0600391103

    View details for Web of Science ID 000238872900070

    View details for PubMedID 16782816

  • Land market feedbacks can undermine biodiversity conservation PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Armsworth, P. R., Daily, G. C., Kareiva, P., Sanchirico, J. N. 2006; 103 (14): 5403-5408


    The full or partial purchase of land has become a cornerstone of efforts to conserve biodiversity in countries with strong private property rights. Methods used to target areas for acquisition typically ignore land market dynamics. We show how conservation purchases affect land prices and generate feedbacks that can undermine conservation goals, either by displacing development toward biologically valuable areas or by accelerating its pace. The impact of these market feedbacks on the effectiveness of conservation depends on the ecological value of land outside nature reserves. Traditional, noneconomic approaches to site prioritization should perform adequately in places where land outside reserves supports little biodiversity. However, these approaches will perform poorly in locations where the countryside surrounding reserves is important for species' persistence. Conservation investments can sometimes even be counterproductive, condemning more species than they save. Conservation is most likely to be compromised in the absence of accurate information on species distributions, which provides a strong argument for improving inventories of biodiversity. Accounting for land market dynamics in conservation planning is crucial for making smart investment decisions.

    View details for DOI 10.1073/pnas.0505278103

    View details for Web of Science ID 000236636400031

    View details for PubMedID 16554375

  • Diversity, natural history and conservation of mammals from San Vito de Coto Brus, Costa Rica. REVISTA DE BIOLOGIA TROPICAL Pacheco, J., Ceballos, G., Daily, G. C., Ehrlich, P. R., Suzan, G., Rodriguez-Herrera, B., Marce, E. 2006; 54 (1): 219-240


    Although Costa Rica has been biologically well studied, few areas have complete mammal inventories, which are essential for ecological studies and conservation. The San Vito region is considered among the most important for scientific research in the country because of the presence of the Wilson Botanical Garden and Las Cruces. However, the knowledge of its mammalian fauna is incomplete. We extensively studied the mammals of San Vito, compiled a checklist, and evaluated its composition, relative abundance, habitat distribution, and conservation status. We recorded 105 species, representing 85 genera, 29 families, and 10 orders. Non-volant mammals represented 62 species, 59 genera, 23 families, and 9 orders. Bats belonged to 6 families, 26 genera and 43 species. The extensive deforestation and hunting have caused the extinction of seven species, but the region still supports, surprisingly, a relatively high number of species, most of which are rare. Few species are common and abundant. Species richness was higher in forest, and forest fragments; fewer species were found in coffee plantations, induced grasslands, and secondary vegetation. Around 21% (13 species) are included in the IUCN red book. Three species are considered endangered (Saimiri oerstedii, Tapirus bairdii, and Sylvilagus dicei), and two threatened (Myrmecophaga trydactila and Caluromys derbianus), of which two (T. bairdii and M. trydactila) are locally extinct. The other species in IUCN are either of low risk (i.e. Chironectes minimus) or data deficient (Lontra longicaudis). Additionally, 24 species (39%) are included in CITES.

    View details for Web of Science ID 000243514100022

    View details for PubMedID 18457190

  • Global consequences of land use SCIENCE Foley, J. A., Defries, R., Asner, G. P., Barford, C., Bonan, G., Carpenter, S. R., Chapin, F. S., Coe, M. T., Daily, G. C., Gibbs, H. K., Helkowski, J. H., Holloway, T., Howard, E. A., Kucharik, C. J., Monfreda, C., Patz, J. A., Prentice, I. C., Ramankutty, N., Snyder, P. K. 2005; 309 (5734): 570-574


    Land use has generally been considered a local environmental issue, but it is becoming a force of global importance. Worldwide changes to forests, farmlands, waterways, and air are being driven by the need to provide food, fiber, water, and shelter to more than six billion people. Global croplands, pastures, plantations, and urban areas have expanded in recent decades, accompanied by large increases in energy, water, and fertilizer consumption, along with considerable losses of biodiversity. Such changes in land use have enabled humans to appropriate an increasing share of the planet's resources, but they also potentially undermine the capacity of ecosystems to sustain food production, maintain freshwater and forest resources, regulate climate and air quality, and ameliorate infectious diseases. We face the challenge of managing trade-offs between immediate human needs and maintaining the capacity of the biosphere to provide goods and services in the long term.

    View details for DOI 10.1126/science.1111772

    View details for Web of Science ID 000230735200036

    View details for PubMedID 16040698

  • Ecosystem consequences of bird declines PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Sekercioglu, C. H., Daily, G. C., Ehrlich, P. R. 2004; 101 (52): 18042-18047


    We present a general framework for characterizing the ecological and societal consequences of biodiversity loss and applying it to the global avifauna. To investigate the potential ecological consequences of avian declines, we developed comprehensive databases of the status and functional roles of birds and a stochastic model for forecasting change. Overall, 21% of bird species are currently extinction-prone and 6.5% are functionally extinct, contributing negligibly to ecosystem processes. We show that a quarter or more of frugivorous and omnivorous species and one-third or more of herbivorous, piscivorous, and scavenger species are extinction-prone. Furthermore, our projections indicate that by 2100, 6-14% of all bird species will be extinct, and 7-25% (28-56% on oceanic islands) will be functionally extinct. Important ecosystem processes, particularly decomposition, pollination, and seed dispersal, will likely decline as a result.

    View details for DOI 10.1073/pnas.0408049101

    View details for Web of Science ID 000226102700030

    View details for PubMedID 15601765

  • Economic value of tropical forest to coffee production PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Ricketts, T. H., Daily, G. C., Ehrlich, P. R., Michener, C. D. 2004; 101 (34): 12579-12582


    Can economic forces be harnessed for biodiversity conservation? The answer hinges on characterizing the value of nature, a tricky business from biophysical, socioeconomic, and ethical perspectives. Although the societal benefits of native ecosystems are clearly immense, they remain largely unquantified for all but a few services. Here, we estimate the value of tropical forest in supplying pollination services to agriculture. We focus on coffee because it is one of the world's most valuable export commodities and is grown in many of the world's most biodiverse regions. Using pollination experiments along replicated distance gradients, we found that forest-based pollinators increased coffee yields by 20% within approximately 1 km of forest. Pollination also improved coffee quality near forest by reducing the frequency of "peaberries" (i.e., small misshapen seeds) by 27%. During 2000-2003, pollination services from two forest fragments (46 and 111 hectares) translated into approximately 60,000 USD per year for one Costa Rican farm. This value is commensurate with expected revenues from competing land uses and far exceeds current conservation incentive payments. Conservation investments in human-dominated landscapes can therefore yield double benefits: for biodiversity and agriculture.

    View details for Web of Science ID 000223596200034

    View details for PubMedID 15306689

  • Alleviating spatial conflict between people and biodiversity PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Luck, G. W., Ricketts, T. H., Daily, G. C., Imhoff, M. 2004; 101 (1): 182-186


    Human settlements are expanding in species-rich regions and pose a serious threat to biodiversity conservation. We quantify the degree to which this threat manifests itself in two contrasting continents, Australia and North America, and suggest how it can be substantially alleviated. Human population density has a strong positive correlation with species richness in Australia for birds, mammals, amphibians, and butterflies (but not reptiles) and in North America for all five taxa. Nevertheless, conservation investments could secure locations that harbor almost all species while greatly reducing overlap with densely populated regions. We compared two conservation-planning scenarios that each aimed to represent all species at least once in a minimum set of sampling sites. The first scenario assigned equal cost to each site (ignoring differences in human population density); the second assigned a cost proportional to the site's human population density. Under the equal-cost scenario, 13-40% of selected sites occurred where population density values were highest (in the top decile). However, this overlap was reduced to as low as 0%, and in almost all cases to <10%, under the population-cost scenario, when sites of high population density were avoided where possible. Moreover, this reduction of overlap was achieved with only small increases in the total amount of area requiring protection. As densely populated regions continue to expand rapidly and drive up land values, the strategic conservation investments of the kind highlighted in our analysis are best made now.

    View details for DOI 10.1073/pnas.2237148100

    View details for Web of Science ID 000187937200035

    View details for PubMedID 14681554

  • Effects of household dynamics on resource consumption and biodiversity NATURE Liu, J. G., Daily, G. C., Ehrlich, P. R., Luck, G. W. 2003; 421 (6922): 530-533


    Human population size and growth rate are often considered important drivers of biodiversity loss, whereas household dynamics are usually neglected. Aggregate demographic statistics may mask substantial changes in the size and number of households, and their effects on biodiversity. Household dynamics influence per capita consumption and thus biodiversity through, for example, consumption of wood for fuel, habitat alteration for home building and associated activities, and greenhouse gas emissions. Here we report that growth in household numbers globally, and particularly in countries with biodiversity hotspots (areas rich in endemic species and threatened by human activities), was more rapid than aggregate population growth between 1985 and 2000. Even when population size declined, the number of households increased substantially. Had the average household size (that is, the number of occupants) remained static, there would have been 155 million fewer households in hotspot countries in 2000. Reduction in average household size alone will add a projected 233 million additional households to hotspot countries during the period 2000-15. Rapid increase in household numbers, often manifested as urban sprawl, and resultant higher per capita resource consumption in smaller households pose serious challenges to biodiversity conservation.

    View details for DOI 10.1038/nature01359

    View details for Web of Science ID 000180670600044

    View details for PubMedID 12540852

  • Disappearance of insectivorous birds from tropical forest fragments PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Sekercioglu, C. H., Ehrlich, P. R., Daily, G. C., Aygen, D., Goehring, D., Sandi, R. F. 2002; 99 (1): 263-267


    Determining the impact of forest disturbance and fragmentation on tropical biotas is a central goal of conservation biology. Among tropical forest birds, understory insectivores are particularly sensitive to habitat disturbance and fragmentation, despite their relatively small sizes and freedom from hunting pressure. Why these birds are especially vulnerable to fragmentation is not known. Our data indicate that the best determinant of the persistence of understory insectivorous birds in small fragments is the ability to disperse through deforested countryside habitats. This finding contradicts our initial hypothesis that the decline of insectivorous birds in forest fragments is caused by impoverished invertebrate prey base in fragments. Although we observed significantly fewer insectivorous birds in smaller fragments, extensive sampling of invertebrate communities (106,082 individuals) and avian diets (of 735 birds) revealed no important differences between large and small fragments. Neither habitat specificity nor drier fragment microclimates seemed critical. Bird species that were less affected by forest fragmentation were, in general, those that used the deforested countryside more, and we suggest that the key to their conservation will be found there.

    View details for Web of Science ID 000173233300049

    View details for PubMedID 11782549

  • Ecological forecasts NATURE Daily, G. C. 2001; 411 (6835): 245-245

    View details for Web of Science ID 000168710000024

    View details for PubMedID 11357107

  • Conserving biodiversity and ecosystem services SCIENCE Balvanera, P., Daily, G. C., Ehrlich, P. R., Ricketts, T. H., Bailey, S. A., Kark, S., Kremen, C., Pereira, H. 2001; 291 (5511): 2047-2047

    View details for Web of Science ID 000167563800001

    View details for PubMedID 11256386

  • Ecology - The value of nature and the nature of value SCIENCE Daily, G. C., Soderqvist, T., Aniyar, S., Arrow, K., Dasgupta, P., Ehrlich, P. R., Folke, C., Jansson, A., Jansson, B. O., Kautsky, N., Levin, S., Lubchenco, J., Maler, K. G., Simpson, D., Starrett, D., Tilman, D., Walker, B. 2000; 289 (5478): 395-396


    Ecosystems are capital assets: When properly managed, they yield a flow of vital goods and services. Relative to other forms of capital, however, ecosystems are poorly understood, scarcely monitored, and--in many important cases--undergoing rapid degradation. The process of economic valuation could greatly improve stewardship. This potential is now being realized with innovative financial instruments and institutional arrangements.

    View details for Web of Science ID 000088305500022

    View details for PubMedID 10939949

  • Economic incentives for rain forest conservation across scales SCIENCE Kremen, C., Niles, J. O., Dalton, M. G., Daily, G. C., Ehrlich, P. R., Fay, J. P., Grewal, D., Guillery, R. P. 2000; 288 (5472): 1828-1832


    Globally, tropical deforestation releases 20 to 30% of anthropogenic greenhouse gases. Conserving forests could reduce emissions, but the cost-effectiveness of this mechanism for mitigation depends on the associated opportunity costs. We estimated these costs from local, national, and global perspectives using a case study from Madagascar. Conservation generated significant benefits over logging and agriculture locally and globally. Nationally, however, financial benefits from industrial logging were larger than conservation benefits. Such differing economic signals across scales may exacerbate tropical deforestation. The Kyoto Protocol could potentially overcome this obstacle to conservation by creating markets for protection of tropical forests to mitigate climate change.

    View details for Web of Science ID 000087503800051

    View details for PubMedID 10846165

  • Seeking the great transition NATURE Daily, G. C., Walker, B. H. 2000; 403 (6767): 243-245

    View details for Web of Science ID 000084899700022

    View details for PubMedID 10659827

  • Food production, population growth, and the environment. Science Daily, G., Dasgupta, P., Bolin, B., Crosson, P., du Guerny, J., Ehrlich, P., Folke, C., Jansson, A. M., Jansson, B., Kautsky, N., Kinzig, A., Levin, S., Mäler, K. G., Pinstrup-Andersen, P., Siniscalco, D., Walker, B. 1998; 281 (5381): 1291-1292

    View details for Web of Science ID 000075666800027

    View details for PubMedID 9735046

  • Population diversity: Its extent and extinction SCIENCE Hughes, J. B., Daily, G. C., Ehrlich, P. R. 1997; 278 (5338): 689-692


    Genetically distinct populations are an important component of biodiversity. This work estimates the number of populations per area of a sample of species from literature on population differentiation and the average range area of a species from a sample of distribution maps. This yields an estimate of about 220 populations per species, or 1.1 to 6.6 billion populations globally. Assuming that population extinction is a linear function of habitat loss, approximately 1800 populations per hour (16 million annually) are being destroyed in tropical forests alone.

    View details for Web of Science ID A1997YC32300055

    View details for PubMedID 9381179

  • Nocturnality and species survival PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Daily, G. C., Ehrlich, P. R. 1996; 93 (21): 11709-11712


    Surveys of butterfly and moth diversity in tropical forest fragments suggest that nocturnality confers a dispersal, and possibly a survival, advantage. The butterfly faunas of smaller fragments were depauperate; in contrast, the species richness of nocturnal moths was similar in all fragments and even in pasture. The lack of correlation between butterfly and moth species richness among fragments (r2 = 0.005) is best explained by movements of moths at night when ambient conditions in forest and pasture are most similar; butterflies face substantial daytime temperature, humidity, and solar radiation barriers. This interpretation is supported by information on birds, beetles, and bats.

    View details for Web of Science ID A1996VM68100075

    View details for PubMedID 8876201



    Roughly 43 percent of Earth's terrestrial vegetated surface has diminished capacity to supply benefits to humanity because of recent, direct impacts of land use. This represents an approximately 10 percent reduction in potential direct instrumental value (PDIV), defined as the potential to yield direct benefits such as agricultural, forestry, industrial, and medicinal products. If present trends continue, the global loss of PDIV could reach approximately 20 percent by 2020. From a biophysical perspective, recovery of approximately 5 percent of PDIV is feasible over the next 25 years. Capitalizing on natural recovery mechanisms is urgently needed to prevent further irreversible degradation and to retain the multiple values of productive land.

    View details for Web of Science ID A1995RK42700033

    View details for PubMedID 17841252



    Species in a Colorado subalpine ecosystem show subtle interdependences. Red-naped sapsuckers play two distinct keystone roles. They excavate nest cavities in fungus-infected aspens that are required as nest sites by two species of swallows, and they drill sap wells into willows that provide abundant nourishment for themselves, hummingbirds, orange-crowned warblers, chipmunks, and an array of other sap robbers. The swallows thus depend on, and the sap robbers benefit from, a keystone species complex comprised of sapsuckers, willows, aspens, and a heartwood fungus. Disappearance of any element of the complex could cause an unanticipated unraveling of the community.

    View details for Web of Science ID A1993KH51600048

    View details for PubMedID 11607351


    View details for Web of Science ID A1993NG62200008

    View details for PubMedID 12290839



    A simple, globally aggregated, stochastic-simulation model was constructed to examine the effects of rapid climatic change on agriculture and the human population. The model calculates population size and the production, consumption and storage of grain under different climate scenarios over a 20-year projection time. In most scenarios, either an optimistic baseline annual increase of agricultural output of 1.7% or a more pessimistic appraisal of 0.9% was used. The rate of natural increase of the human population exclusive of excess hunger-related deaths was set as 1.7% per year and climatic changes with both negative and positive impacts on agriculture were assessed. Analysis of the model suggests that the number of hunger-related deaths could double (with reference to an estimated 200 million deaths in the past two decades) if grain production keeps pace with population growth but climatic conditions are unfavourable. If the rate of increase in grain production is about half that of population growth, the number of hunger-related deaths could increase about fivefold (over past levels); the impact of climatic change is relatively small under this imbalance. Even favourable climatic changes that enhance agricultural production may not prevent a fourfold increase in deaths (over past levels) under scenarios where population growth outpaces production by about 0.8% per annum. These results may foreshadow a fundamental change where, for the first time, absolute global food deficits compound inequities in food production and distribution in causing famine. The model also highlights the effectiveness of reducing population growth rates as a strategy for minimizing the impact of global climate change and maintaining food supplies for everyone.

    View details for Web of Science ID A1990ED14900012

    View details for PubMedID 1979448