I am a theoretical ecologist by formation, I am generally interested in investigating factors and processes driving the dynamics of natural and harvested populations and in understanding how to use this knowledge to inform practical management.

In recent years I have been particularly interested in investigating factors and processes that provide resilience of natural or managed population to natural and anthropogenic stressors, environmental shocks and climate change. I study resilience from two very different points of view: on the one hand, I have focused my attention on populations that prove to be resilient despite our effort to control or eradicate them, namely parasitic and infectious diseases. On the other hand, I have been working extensively to understand how to increase resilience of population of commercial or conservation interest to extensive harvesting, environmental shocks, climate change and land use change.

I have been working on a number of theoretical and applied problems ranging from the conservation of the European eel to the sustainable management of the abalone fishery in Baja California in the face of climate change, the biocontrol of schistososmiasis in west Africa and the relationship between resource exploitation, infectious diseases and poverty traps.

Academic Appointments

Boards, Advisory Committees, Professional Organizations

  • Faculty Fellow, Stanford Center for Innovation in Global Health (2015 - Present)

Professional Education

  • Ph.D., University of Parma & University of Ferrara, Ecology (1993)
  • B.E. & M.Sc., Politecnico di Milano, Civil and Environmental Engineering (1989)

Current Research and Scholarly Interests

I am a population biologist and my primary research interest is the use of ecological theory, particularly life history-based models, in population dynamics and management. I make use of advanced mathematical and computational techniques to analyse a wide variety of ecological problems ranging from the identification of basic first-principles in the ecology of infectious diseases, to the analysis of costs and benefits of alternative policies for natural resource management in a multi-objective, multi-attribute framework, to the investigation of population dynamics and extinction risk in endangered populations. I dedicated a considerable effort to assess the effect of anthopogenic pressures as well as of ecological and environmental heterogeneities - including temperature, oxygen and pH anomalies - on population dynamics and management of marine resources and to estimate key parameters that may be incorporated into population models useful for decision-making. I have been working for more than two decades on the demography and management of the European eel (A. anguilla) and, more recently, the conservation of marble trout (S. marmoratus), the optimal bioeconomic management of mollusc farming, the problem of algal bloom control in Adriatic coastal lagoons and the development of Rapid Assessment Methods to assess the status of coastal lagoons. I am currently investigating how the interaction between networks of Marine Protected Areas and different schemes of fishery management might impact the resilience, productivity and persistence of the abalone fisheries in Baja California, Mexico under alternative scenarios of climate change, including increase frequency and intensity of low oxygen, low pH and variable temperature.
I recently started to work on the bio-control of schistosomiasis in Senegal with dr. Sanna Sokolow and I keep working with Luca Bolzoni on the optimal control of infectious diseases in the wildlife and in farmed animals.
My interest for pursuing solutions for a more sustainable world brought me to take a non-academic, governmental job from 2001 to 2004 as director of the Program for Technological Innovation and Sustainable Development for the Environmental Protection Agency of the Lombardy region (Italy), where I developed agreements with business and industrial associations to foster the adoption of environmental management schemes and to improve corporate environmental performances.
I am currently associated editor of Ecology Letters and reviewers for several ecological journals. From 1999 to 2005 I was president of the Italian Association of Environmental Engineering (AIAT), member of the administration board of WWF Italy (2005-2007) and, from 2007 to 2012, chair of the Ethics and Sustainability Committee of Eurizon Capital, the investment management company of Intesa SanPaolo, the first Italian Bank. In the effort to increase awareness about the threats imposed by climate change and to foster actions to curb emissions, increase energy efficiency and saving, I wrote a book “Energia e Salute della Terra” (Energy and Planet Health, Fondazione Boroli publisher) that was distributed to 40 thousands students in high schools and colleges in Italy.
I hold a BE in Civil Engineering and a MS in Environmental Engineering from Politecnico di Milano (1989, Italy), a PhD in Applied Ecology from the Universities of Ferrara and Parma (1993, Italy) a three years research experience at Princeton University (1994-1996) and three more years (1996-1998) back to Politecnico di Milano . After more than a decade at the University of Parma, in 2012 I happily moved to Stanford as full time faculty.

Stanford Advisees

Graduate and Fellowship Programs

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

All Publications

  • Nearly 400 million people are at higher risk of schistosomiasis because dams block the migration of snail-eating river prawns PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES Sokolow, S. H., Jones, I. J., Jocque, M., La, D., Cords, O., Knight, A., Lund, A., Wood, C. L., Lafferty, K. D., Hoover, C. M., Collender, P. A., Remais, J. V., Lopez-Carr, D., Fisk, J., Kuris, A. M., De Leo, G. A. 2017; 372 (1722)


    Dams have long been associated with elevated burdens of human schistosomiasis, but how dams increase disease is not always clear, in part because dams have many ecological and socio-economic effects. A recent hypothesis argues that dams block reproduction of the migratory river prawns that eat the snail hosts of schistosomiasis. In the Senegal River Basin, there is evidence that prawn populations declined and schistosomiasis increased after completion of the Diama Dam. Restoring prawns to a water-access site upstream of the dam reduced snail density and reinfection rates in people. However, whether a similar cascade of effects (from dams to prawns to snails to human schistosomiasis) occurs elsewhere is unknown. Here, we examine large dams worldwide and identify where their catchments intersect with endemic schistosomiasis and the historical habitat ranges of large, migratory Macrobrachium spp. prawns. River prawn habitats are widespread, and we estimate that 277-385 million people live within schistosomiasis-endemic regions where river prawns are or were present (out of the 800 million people who are at risk of schistosomiasis). Using a published repository of schistosomiasis studies in sub-Saharan Africa, we compared infection before and after the construction of 14 large dams for people living in: (i) upstream catchments within historical habitats of native prawns, (ii) comparable undammed watersheds, and (iii) dammed catchments beyond the historical reach of migratory prawns. Damming was followed by greater increases in schistosomiasis within prawn habitats than outside prawn habitats. We estimate that one third to one half of the global population-at-risk of schistosomiasis could benefit from restoration of native prawns. Because dams block prawn migrations, our results suggest that prawn extirpation contributes to the sharp increase of schistosomiasis after damming, and points to prawn restoration as an ecological solution for reducing human disease.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.2016.0127

    View details for Web of Science ID 000399956400008

    View details for PubMedID 28438916

  • Big-data-driven modeling unveils country-wide drivers of endemic schistosomiasis SCIENTIFIC REPORTS Mari, L., Gatto, M., Ciddio, M., Dia, E. D., Sokolow, S. H., De Leo, G. A., Casagrandi, R. 2017; 7


    Schistosomiasis is a parasitic infection that is widespread in sub-Saharan Africa, where it represents a major health problem. We study the drivers of its geographical distribution in Senegal via a spatially explicit network model accounting for epidemiological dynamics driven by local socioeconomic and environmental conditions, and human mobility. The model is parameterized by tapping several available geodatabases and a large dataset of mobile phone traces. It reliably reproduces the observed spatial patterns of regional schistosomiasis prevalence throughout the country, provided that spatial heterogeneity and human mobility are suitably accounted for. Specifically, a fine-grained description of the socioeconomic and environmental heterogeneities involved in local disease transmission is crucial to capturing the spatial variability of disease prevalence, while the inclusion of human mobility significantly improves the explanatory power of the model. Concerning human movement, we find that moderate mobility may reduce disease prevalence, whereas either high or low mobility may result in increased prevalence of infection. The effects of control strategies based on exposure and contamination reduction via improved access to safe water or educational campaigns are also analyzed. To our knowledge, this represents the first application of an integrative schistosomiasis transmission model at a whole-country scale.

    View details for DOI 10.1038/s41598-017-00493-1

    View details for Web of Science ID 000397528600021

    View details for PubMedID 28352101

  • The Potential Role of Direct and Indirect Contacts on Infection Spread in Dairy Farm Networks. PLoS computational biology Rossi, G., De Leo, G. A., Pongolini, S., Natalini, S., Zarenghi, L., Ricchi, M., Bolzoni, L. 2017; 13 (1)


    Animals' exchanges are considered the most effective route of between-farm infectious disease transmission. However, despite being often overlooked, the infection spread due to contaminated equipment, vehicles, or personnel proved to be important for several livestock epidemics. This study investigated the role of indirect contacts in a potential infection spread in the dairy farm network of the Province of Parma (Northern Italy). We built between-farm contact networks using data on cattle exchange (direct contacts), and on-farm visits by veterinarians (indirect contacts). We compared the features of the contact structures by using measures on static and temporal networks. We assessed the disease spreading potential of the direct and indirect network structures in the farm system by using data on the infection state of farms by paratuberculosis. Direct and indirect networks showed non-trivial differences with respect to connectivity, contact distribution, and super-spreaders identification. Furthermore, our analyses on paratuberculosis data suggested that the contributions of direct and indirect contacts on diseases spread are apparent at different spatial scales. Our results highlighted the potential role of indirect contacts in between-farm disease spread and underlined the need for a deeper understanding of these contacts to develop better strategies for prevention of livestock epidemics.

    View details for DOI 10.1371/journal.pcbi.1005301

    View details for PubMedID 28125610

    View details for PubMedCentralID PMC5268397

  • Ocean warming and the demography of declines in coral body size MARINE ECOLOGY PROGRESS SERIES Elahi, R., Sebens, K. P., De Leo, G. A. 2016; 560: 147-158

    View details for DOI 10.3354/meps11931

    View details for Web of Science ID 000390104900010

  • Global Assessment of Schistosomiasis Control Over the Past Century Shows Targeting the Snail Intermediate Host Works Best. PLoS neglected tropical diseases Sokolow, S. H., Wood, C. L., Jones, I. J., Swartz, S. J., Lopez, M., Hsieh, M. H., Lafferty, K. D., Kuris, A. M., Rickards, C., De Leo, G. A. 2016; 10 (7)


    Despite control efforts, human schistosomiasis remains prevalent throughout Africa, Asia, and South America. The global schistosomiasis burden has changed little since the new anthelmintic drug, praziquantel, promised widespread control.We evaluated large-scale schistosomiasis control attempts over the past century and across the globe by identifying factors that predict control program success: snail control (e.g., molluscicides or biological control), mass drug administrations (MDA) with praziquantel, or a combined strategy using both. For data, we compiled historical information on control tactics and their quantitative outcomes for all 83 countries and territories in which: (i) schistosomiasis was allegedly endemic during the 20th century, and (ii) schistosomiasis remains endemic, or (iii) schistosomiasis has been "eliminated," or is "no longer endemic," or transmission has been interrupted.Widespread snail control reduced prevalence by 92 ± 5% (N = 19) vs. 37 ± 7% (N = 29) for programs using little or no snail control. In addition, ecological, economic, and political factors contributed to schistosomiasis elimination. For instance, snail control was most common and widespread in wealthier countries and when control began earlier in the 20th century.Snail control has been the most effective way to reduce schistosomiasis prevalence. Despite evidence that snail control leads to long-term disease reduction and elimination, most current schistosomiasis control efforts emphasize MDA using praziquantel over snail control. Combining drug-based control programs with affordable snail control seems the best strategy for eliminating schistosomiasis.

    View details for DOI 10.1371/journal.pntd.0004794

    View details for PubMedID 27441556

    View details for PubMedCentralID PMC4956325

  • Body size and meta-community structure: the allometric scaling of parasitic worm communities in their mammalian hosts PARASITOLOGY De Leo, G. A., Dobson, A. P., Gatto, M. 2016; 143 (7): 880-893


    In this paper we derive from first principles the expected body sizes of the parasite communities that can coexist in a mammal of given body size. We use a mixture of mathematical models and known allometric relationships to examine whether host and parasite life histories constrain the diversity of parasite species that can coexist in the population of any host species. The model consists of one differential equation for each parasite species and a single density-dependent nonlinear equation for the affected host under the assumption of exploitation competition. We derive threshold conditions for the coexistence and competitive exclusion of parasite species using invasion criteria and stability analysis of the resulting equilibria. These results are then used to evaluate the range of parasites species that can invade and establish in a target host and identify the 'optimal' size of a parasite species for a host of a given body size; 'optimal' is defined as the body size of a parasite species that cannot be outcompeted by any other parasite species. The expected distributions of parasites body sizes in hosts of different sizes are then compared with those observed in empirical studies. Our analysis predicts the relative abundance of parasites of different size that establish in the host and suggests that increasing the ratio of parasite body size to host body size above a minimum threshold increases the persistence of the parasite population.

    View details for DOI 10.1017/S0031182015001444

    View details for Web of Science ID 000376781100008

    View details for PubMedID 27001526

  • Quantifying 60 years of declining European eel (Anguilla anguilla L., 1758) fishery yields in Mediterranean coastal lagoons ICES JOURNAL OF MARINE SCIENCE Aalto, E., Capoccioni, F., Mas, J. T., Schiavina, M., Leone, C., De Leo, G., Ciccotti, E. 2016; 73 (1): 101-110
  • Infection with schistosome parasites in snails leads to increased predation by prawns: implications for human schistosomiasis control JOURNAL OF EXPERIMENTAL BIOLOGY Swartz, S. J., De Leo, G. A., Wood, C. L., Sokolow, S. H. 2015; 218 (24): 3962-3967

    View details for DOI 10.1242/jeb.129221

    View details for Web of Science ID 000366645500015

    View details for PubMedID 26677260

  • The good, the bad and the ugly of marine reserves for fishery yields PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES De Leo, G. A., Micheli, F. 2015; 370 (1681)

    View details for DOI 10.1098/rstb.2014.0276

    View details for Web of Science ID 000362720200008

    View details for PubMedID 26460129

  • Reconciling predator conservation with public safety FRONTIERS IN ECOLOGY AND THE ENVIRONMENT Ferretti, F., Jorgensen, S., Chapple, T. K., De Leo, G., Micheli, F. 2015; 13 (8): 412-417

    View details for DOI 10.1890/150109

    View details for Web of Science ID 000362229100014

  • A Theoretical Analysis of the Geography of Schistosomiasis in Burkina Faso Highlights the Roles of Human Mobility and Water Resources Development in Disease Transmission PLOS NEGLECTED TROPICAL DISEASES Perez-Saez, J., Mari, L., Bertuzzo, E., Casagrandi, R., Sokolow, S. H., De Leo, G. A., Mande, T., Ceperley, N., Froehlich, J., Sou, M., Karambiri, H., Yacouba, H., Maiga, A., Gatto, M., Rinaldo, A. 2015; 9 (10)

    View details for DOI 10.1371/journal.pntd.0004127

    View details for Web of Science ID 000364459600033

    View details for PubMedID 26513655

  • A global viability assessment of the European eel GLOBAL CHANGE BIOLOGY Bevacqua, D., Melia, P., Gatto, M., De Leo, G. A. 2015; 21 (9): 3323-3335

    View details for DOI 10.1111/gcb.12972

    View details for Web of Science ID 000360998400013

    View details for PubMedID 25965113

  • ECOLOGICAL THEORY. A general consumer-resource population model. Science Lafferty, K. D., DeLeo, G., Briggs, C. J., Dobson, A. P., Gross, T., Kuris, A. M. 2015; 349 (6250): 854-857


    Food-web dynamics arise from predator-prey, parasite-host, and herbivore-plant interactions. Models for such interactions include up to three consumer activity states (questing, attacking, consuming) and up to four resource response states (susceptible, exposed, ingested, resistant). Articulating these states into a general model allows for dissecting, comparing, and deriving consumer-resource models. We specify this general model for 11 generic consumer strategies that group mathematically into predators, parasites, and micropredators and then derive conditions for consumer success, including a universal saturating functional response. We further show how to use this framework to create simple models with a common mathematical lineage and transparent assumptions. Underlying assumptions, missing elements, and composite parameters are revealed when classic consumer-resource models are derived from the general model.

    View details for DOI 10.1126/science.aaa6224

    View details for PubMedID 26293960

  • A general consumer-resource population model SCIENCE Lafferty, K. D., DeLeo, G., Briggs, C. J., Dobson, A. P., Gross, T., Kuris, A. M. 2015; 349 (6250): 854-857
  • Reduced transmission of human schistosomiasis after restoration of a native river prawn that preys on the snail intermediate host PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Sokolow, S. H., Huttinger, E., Jouanard, N., Hsieh, M. H., Lafferty, K. D., Kuris, A. M., Riveau, G., Senghor, S., Thiam, C., N'Diaye, A., Faye, D. S., De Leo, G. A. 2015; 112 (31): 9650-9655


    Eliminating human parasitic disease often requires interrupting complex transmission pathways. Even when drugs to treat people are available, disease control can be difficult if the parasite can persist in nonhuman hosts. Here, we show that restoration of a natural predator of a parasite's intermediate hosts may enhance drug-based schistosomiasis control. Our study site was the Senegal River Basin, where villagers suffered a massive outbreak and persistent epidemic after the 1986 completion of the Diama Dam. The dam blocked the annual migration of native river prawns (Macrobrachium vollenhoveni) that are voracious predators of the snail intermediate hosts for schistosomiasis. We tested schistosomiasis control by reintroduced river prawns in a before-after-control-impact field experiment that tracked parasitism in snails and people at two matched villages after prawns were stocked at one village's river access point. The abundance of infected snails was 80% lower at that village, presumably because prawn predation reduced the abundance and average life span of latently infected snails. As expected from a reduction in infected snails, human schistosomiasis prevalence was 18 ± 5% lower and egg burden was 50 ± 8% lower at the prawn-stocking village compared with the control village. In a mathematical model of the system, stocking prawns, coupled with infrequent mass drug treatment, eliminates schistosomiasis from high-transmission sites. We conclude that restoring river prawns could be a novel contribution to controlling, or eliminating, schistosomiasis.

    View details for DOI 10.1073/pnas.1502651112

    View details for Web of Science ID 000358930600060

    View details for PubMedID 26195752

  • Epidemiological modelling for the assessment of bovine tuberculosis surveillance in the dairy farm network in Emilia-Romagna (Italy) EPIDEMICS Rossi, G., De Leo, G. A., Pongolini, S., Natalini, S., Vincenzi, S., Bolzoni, L. 2015; 11: 62-70


    Assessing the performance of a surveillance system for infectious diseases of domestic animals is a challenging task for health authorities. Therefore, it is important to assess what strategy is the most effective in identifying the onset of an epidemic and in minimizing the number of infected farms. The aim of the present work was to evaluate the performance of the bovine tuberculosis (bTB) surveillance system in the network of dairy farms in the Emilia-Romagna (ER) Region, Italy. A bTB-free Region since 2007, ER implements an integrated surveillance strategy based on three components, namely routine on-farm tuberculin skin-testing performed every 3 years, tuberculin skin-testing of cattle exchanged between farms, and post-mortem inspection at slaughterhouses. We assessed the effectiveness of surveillance by means of a stochastic network model of both within-farm and between-farm bTB dynamics calibrated on data available for ER dairy farms. Epidemic dynamics were simulated for five scenarios: the current ER surveillance system, a no surveillance scenario that we used as the benchmark to characterize epidemic dynamics, three additional scenarios in which one of the surveillance components was removed at a time so as to outline its significance in detecting the infection. For each scenario we ran Monte Carlo simulations of bTB epidemics following the random introduction of an infected individual in the network. System performances were assessed through the comparative analysis of a number of statistics, including the time required for epidemic detection and the total number of infected farms during the epidemic. Our analysis showed that slaughterhouse inspection is the most effective surveillance component in reducing the time for disease detection, while routine surveillance in reducing the number of multi-farms epidemics. On the other hand, testing exchanged cattle improved the performance of the surveillance system only marginally.

    View details for DOI 10.1016/j.epidem.2015.02.007

    View details for Web of Science ID 000354403100008

    View details for PubMedID 25979283

  • A user-friendly tool to assess management plans for European eel fishery and conservation ENVIRONMENTAL MODELLING & SOFTWARE Schiavina, M., Bevacqua, D., Melia, P., Crivelli, A. J., Gatto, M., De Leo, G. A. 2015; 64: 9-17
  • React or wait: which optimal culling strategy to control infectious diseases in wildlife JOURNAL OF MATHEMATICAL BIOLOGY Bolzoni, L., Tessoni, V., Groppi, M., De Leo, G. A. 2014; 69 (4): 1001-1025


    We applied optimal control theory to an SI epidemic model to identify optimal culling strategies for diseases management in wildlife. We focused on different forms of the objective function, including linear control, quadratic control, and control with limited amount of resources. Moreover, we identified optimal solutions under different assumptions on disease-free host dynamics, namely: self-regulating logistic growth, Malthusian growth, and the case of negligible demography. We showed that the correct characterization of the disease-free host growth is crucial for defining optimal disease control strategies. By analytical investigations of the model with negligible demography, we demonstrated that the optimal strategy for the linear control can be either to cull at the maximum rate at the very beginning of the epidemic (reactive culling) when the culling cost is low, or never to cull, when culling cost is high. On the other hand, in the cases of quadratic control or limited resources, we demonstrated that the optimal strategy is always reactive. Numerical analyses for hosts with logistic growth showed that, in the case of linear control, the optimal strategy is always reactive when culling cost is low. In contrast, if the culling cost is high, the optimal strategy is to delay control, i.e. not to cull at the onset of the epidemic. Finally, we showed that for diseases with the same basic reproduction number delayed control can be optimal for acute infections, i.e. characterized by high disease-induced mortality and fast dynamics, while reactive control can be optimal for chronic ones.

    View details for DOI 10.1007/s00285-013-0726-y

    View details for Web of Science ID 000342173300008

    View details for PubMedID 24057080

  • A risk-based framework for assessing the cumulative impact of multiple fisheries BIOLOGICAL CONSERVATION Micheli, F., De Leo, G., Butner, C., Martone, R. G., Shester, G. 2014; 176: 224-235
  • A system-wide approach to supporting improvements in seafood production practices and outcomes FRONTIERS IN ECOLOGY AND THE ENVIRONMENT Micheli, F., De Leo, G., Shester, G. G., Martone, R. G., Lluch-Cota, S. E., Butner, C., Crowder, L. B., Fujita, R., Gelcich, S., Jams, M., Lester, S. E., McCay, B., Pelc, R., Saenz-Arroyo, A. 2014; 12 (5): 297-305

    View details for DOI 10.1890/110257

    View details for Web of Science ID 000336940100017

  • Does biodiversity protect humans against infectious disease? ECOLOGY Wood, C. L., Lafferty, K. D., DeLeo, G., Young, H. S., Hudson, P. J., Kuris, A. M. 2014; 95 (4): 817-832


    Control of human infectious disease has been promoted as a valuable ecosystem service arising from the conservation of biodiversity. There are two commonly discussed mechanisms by which biodiversity loss could increase rates of infectious disease in a landscape. First, loss of competitors or predators could facilitate an increase in the abundance of competent reservoir hosts. Second, biodiversity loss could disproportionately affect non-competent, or less competent reservoir hosts, which would otherwise interfere with pathogen transmission to human populations by, for example, wasting the bites of infected vectors. A negative association between biodiversity and disease risk, sometimes called the "dilution effect hypothesis," has been supported for a few disease agents, suggests an exciting win-win outcome for the environment and society, and has become a pervasive topic in the disease ecology literature. Case studies have been assembled to argue that the dilution effect is general across disease agents. Less touted are examples in which elevated biodiversity does not affect or increases infectious disease risk for pathogens of public health concern. In order to assess the likely generality of the dilution effect, we review the association between biodiversity and public health across a broad variety of human disease agents. Overall, we hypothesize that conditions for the dilution effect are unlikely to be met for most important diseases of humans. Biodiversity probably has little net effect on most human infectious diseases but, when it does have an effect, observation and basic logic suggest that biodiversity will be more likely to increase than to decrease infectious disease risk.

    View details for DOI 10.1890/13-1041.1

    View details for Web of Science ID 000334573600004

    View details for PubMedID 24933803

  • Rapid estimation of potential yield for data-poor Tapes philippinarum fisheries in North Adriatic coastal lagoons HYDROBIOLOGIA Vincenzi, S., De Leo, G. A., Munari, C., Mistri, M. 2014; 724 (1): 267-277
  • Understanding the effectiveness of marine protected areas using genetic connectivity patterns and Lagrangian simulations DIVERSITY AND DISTRIBUTIONS Pujolar, J. M., Schiavina, M., Di Franco, A., Melia, P., Guidetti, P., Gatto, M., De Leo, G. A., Zane, L. 2013; 19 (12): 1531-1542

    View details for DOI 10.1111/ddi.12114

    View details for Web of Science ID 000329778600007

  • REPRODUCTIVE POTENTIAL CAN PREDICT RECRUITMENT RATES IN ABALONE JOURNAL OF SHELLFISH RESEARCH Rossetto, M., De Leo, G. A., Greenley, A., Vazquez, L., Saenz-Arroyo, A., Espinoza Montes, J. A., Micheli, F. 2013; 32 (1): 161-169
  • Unexpected Consequences of Culling on the Eradication of Wildlife Diseases: The Role of Virulence Evolution AMERICAN NATURALIST Bolzoni, L., De Leo, G. A. 2013; 181 (3): 301-313


    The removal of individuals from an infected population (culling) is a common strategy used to eradicate wildlife diseases. The manipulation of host density can impose strong selective pressures on pathogen virulence by changing the ecological conditions, thus affecting the effectiveness of eradication programs. We present an analysis of the effect of virulence evolution on culling by extending a susceptible-infected model to the case of competing strains with superinfection. To assess both short- and long-term effects, we first carried out the analysis on an ecological timescale, with a two-strain competition model; then we explore the dynamics of a continuum of pathogenic strains on evolutionary timescales using a quantitative genetics approach (when infection and evolutionary processes occur on comparable timescales) and a game-theoretic approach (when evolutionary processes occur on a slower scale). We demonstrate that the competition among pathogenic variants in the presence of superinfection affects outcome of culling campaigns, since increased host mortality may select for less virulent strains able to establish in sparser populations. This can lead to the counterintuitive result that disease abundance and prevalence may even increase with culling, thus making the eradication of infections considerably less likely. This is particularly relevant in the case of zoonoses where higher prevalence and abundance of pathogens in wild reservoirs may increase the risk of spillover in livestock and humans.

    View details for DOI 10.1086/669154

    View details for Web of Science ID 000315927900004

    View details for PubMedID 23448881

  • Effects of heat recovery for district heating on waste incineration health impact: A simulation study in Northern Italy SCIENCE OF THE TOTAL ENVIRONMENT Cordioli, M., Vincenzi, S., De Leo, G. A. 2013; 444: 369-380


    The construction of waste incinerators in populated areas always causes substantial public concern. Since the heat from waste combustion can be recovered to power district heating networks and allows for the switch-off of domestic boilers in urbanized areas, predictive models for health assessment should also take into account the potential benefits of abating an important source of diffuse emission. In this work, we simulated the dispersion of atmospheric pollutants from a waste incinerator under construction in Parma (Italy) into different environmental compartments and estimated the potential health effect of both criteria- (PM(10)) and micro-pollutants (PCDD/F, PAH, Cd, Hg). We analyzed two emission scenarios, one considering only the new incinerator, and the other accounting for the potential decrease in pollutant concentrations due to the activation of a district heating network. We estimated the effect of uncertainty in parameter estimation on health risk through Monte Carlo simulations. In addition, we analyzed the robustness of health risk to alternative assumptions on: a) the geographical origins of the potentially contaminated food, and b) the dietary habits of the exposed population. Our analysis showed that under the specific set of assumptions and emission scenarios explored in the present work: (i) the proposed waste incinerator plant appears to cause negligible harm to the resident population; (ii) despite the net increase in PM(10) mass balance, ground-level concentration of fine particulate matter may be curbed by the activation of an extensive district heating system powered through waste combustion heat recovery and the concurrent switch-off of domestic/industrial heating boilers. In addition, our study showed that the health risk caused by waste incineration emissions is sensitive to assumptions about the typical diet of the resident population, and the geographical origins of food production.

    View details for DOI 10.1016/j.scitotenv.2012.11.079

    View details for Web of Science ID 000316240200040

    View details for PubMedID 23280295

  • A review of exposure assessment methods in epidemiological studies on incinerators. Journal of environmental and public health Cordioli, M., Ranzi, A., De Leo, G. A., Lauriola, P. 2013; 2013: 129470-?


    Incineration is a common technology for waste disposal, and there is public concern for the health impact deriving from incinerators. Poor exposure assessment has been claimed as one of the main causes of inconsistency in the epidemiological literature. We reviewed 41 studies on incinerators published between 1984 and January 2013 and classified them on the basis of exposure assessment approach. Moreover, we performed a simulation study to explore how the different exposure metrics may influence the exposure levels used in epidemiological studies. 19 studies used linear distance as a measure of exposure to incinerators, 11 studies atmospheric dispersion models, and the remaining 11 studies a qualitative variable such as presence/absence of the source. All reviewed studies utilized residence as a proxy for population exposure, although residence location was evaluated with different precision (e.g., municipality, census block, or exact address). Only one study reconstructed temporal variability in exposure. Our simulation study showed a notable degree of exposure misclassification caused by the use of distance compared to dispersion modelling. We suggest that future studies (i) make full use of pollution dispersion models; (ii) localize population on a fine-scale; and (iii) explicitly account for the presence of potential environmental and socioeconomic confounding.

    View details for DOI 10.1155/2013/129470

    View details for PubMedID 23840228

  • Contamination, parasitism and condition of Anguilla anguilla in three Italian stocks ECOTOXICOLOGY Quadroni, S., Galassi, S., Capoccioni, F., Ciccotti, E., Grandi, G., De Leo, G. A., Bettinetti, R. 2013; 22 (1): 94-108


    In conjunction with habitat loss and overfishing, pollution and parasitism are believed to be relevant causes of collapse of Anguilla, as these can affect eel swimming ability and the development of gonads and embryos. The present study investigated Persistent Organic Pollutant (POP) concentrations, infection levels of Anguillicoloides crassus, lipid content and gonad abnormalities in eels sampled in 2007-2008 in three Italian water bodies (Caprolace Lake, Lesina Lagoon and Tevere River) that vary in salinity, trophic condition, contamination level and fishing pressure. Our analysis revealed that low-to-moderate levels of contamination and parasitism were not associated with gonad abnormalities in Caprolace Lake and Lesina Lagoon. On the contrary, POP concentrations and abundances of swim bladder nematodes were remarkably high in eels from the heavily urbanized Tevere River and were associated with significant gonad and swim bladder alterations. Contamination and infestation levels were so high to potentially impair spawner successful migration and reproduction. POP concentrations in Tevere eels also exceeded levels considered safe for food consumption. Though marginally contaminated, eels from the oligotrophic Caprolace Lake were in critical health condition: their lipid reserve was so low as to be considered insufficient to sustain the energetic costs of the transoceanic migration. Lesina eel stock was the only one displaying relatively good quality but here spawner abundance is likely limited by overfishing. Our results suggest that multiple stressors may potentially affect eel reproductive success. More definitive studies are needed to assess whether health effects caused by these multiple stressors are additive, compensatory or synergistic.

    View details for DOI 10.1007/s10646-012-1006-0

    View details for Web of Science ID 000312659600010

    View details for PubMedID 23076840

  • Reproductive Potential Can Predict Recruitment Rates in Abalone Journal of Shellfish Research Rossetto, M., De Leo, G., Greenley, A., Vazquez, L., Saenz- Arroyo, A., et al 2013; 32 (1): 162-169
  • Assessing Dispersal Patterns of Fish Propagules from an Effective Mediterranean Marine Protected Area PLOS ONE Di Franco, A., Coppini, G., Pujolar, J. M., De Leo, G. A., Gatto, M., Lyubartsev, V., Melia, P., Zane, L., Guidetti, P. 2012; 7 (12)


    Successfully enforced marine protected areas (MPAs) have been widely demonstrated to allow, within their boundaries, the recovery of exploited species and beyond their boundaries, the spillover of juvenile and adult fish. Little evidence is available about the so-called 'recruitment subsidy', the augmented production of propagules (i.e. eggs and larvae) due to the increased abundance of large-sized spawners hosted within effective MPAs. Once emitted, propagules can be locally retained and/or exported elsewhere. Patterns of propagule retention and/or export from MPAs have been little investigated, especially in the Mediterranean. This study investigated the potential for propagule production and retention/export from a Mediterranean MPA (Torre Guaceto, SW Adriatic Sea) using the white sea bream, Diplodus sargus sargus, as a model species. A multidisciplinary approach was used combining 1) spatial distribution patterns of individuals (post-settlers and adults) assessed through visual census within Torre Guaceto MPA and in northern and southern unprotected areas, 2) Lagrangian simulations of dispersal based on an oceanographic model of the region and data on early life-history traits of the species (spawning date, pelagic larval duration) and 3) a preliminary genetic study using microsatellite loci. Results show that the MPA hosts higher densities of larger-sized spawners than outside areas, potentially guaranteeing higher propagule production. Model simulations and field observation suggest that larval retention within and long-distance dispersal across MPA boundaries allow the replenishment of the MPA and of exploited populations up to 100 km down-current (southward) from the MPA. This pattern partially agrees with the high genetic homogeneity found in the entire study area (no differences in genetic composition and diversity indices), suggesting a high gene flow. By contributing to a better understanding of propagule dispersal patterns, these findings provide crucial information for the design of MPAs and MPA networks effective to replenish fish stocks and enhance fisheries in unprotected areas.

    View details for DOI 10.1371/journal.pone.0052108

    View details for Web of Science ID 000312794500092

    View details for PubMedID 23284887

  • Evidence That Marine Reserves Enhance Resilience to Climatic Impacts PLOS ONE Micheli, F., Saenz-Arroyo, A., Greenley, A., Vazquez, L., Espinoza Montes, J. A., Rossetto, M., De Leo, G. A. 2012; 7 (7)


    Establishment of marine protected areas, including fully protected marine reserves, is one of the few management tools available for local communities to combat the deleterious effect of large scale environmental impacts, including global climate change, on ocean ecosystems. Despite the common hope that reserves play this role, empirical evidence of the effectiveness of local protection against global problems is lacking. Here we show that marine reserves increase the resilience of marine populations to a mass mortality event possibly caused by climate-driven hypoxia. Despite high and widespread adult mortality of benthic invertebrates in Baja California, Mexico, that affected populations both within and outside marine reserves, juvenile replenishment of the species that supports local economies, the pink abalone Haliotis corrugata, remained stable within reserves because of large body size and high egg production of the protected adults. Thus, local protection provided resilience through greater resistance and faster recovery of protected populations. Moreover, this benefit extended to adjacent unprotected areas through larval spillover across the edges of the reserves. While climate change mitigation is being debated, coastal communities have few tools to slow down negative impacts of global environmental shifts. These results show that marine protected areas can provide such protection.

    View details for DOI 10.1371/journal.pone.0040832

    View details for Web of Science ID 000306548900054

    View details for PubMedID 22855690

  • Translocation of stream-dwelling salmonids in headwaters: insights from a 15-year reintroduction experience REVIEWS IN FISH BIOLOGY AND FISHERIES Vincenzi, S., Crivelli, A. J., Jesensek, D., De Leo, G. A. 2012; 22 (2): 437-455
  • Fishery-Induced Selection for Slow Somatic Growth in European Eel PLOS ONE Bevacqua, D., Capoccioni, F., Melia, P., Vincenzi, S., Pujolar, J. M., De Leo, G. A., Ciccotti, E. 2012; 7 (5)


    Both theoretical and experimental studies have shown that fishing mortality can induce adaptive responses in body growth rates of fishes in the opposite direction of natural selection. We compared body growth rates in European eel (Anguilla anguilla) from three Mediterranean stocks subject to different fishing pressure. Results are consistent with the hypotheses that i) fast-growing individuals are more likely to survive until sexual maturity than slow-growing ones under natural conditions (no fishing) and ii) fishing can select for slow-growing individuals by removing fast-growing ones. Although the possibility of human-induced evolution seems remote for a panmictic species like such as the European eel, further research is desirable to assess the implications of the intensive exploitation on this critically endangered fish.

    View details for DOI 10.1371/journal.pone.0037622

    View details for Web of Science ID 000305345300062

    View details for PubMedID 22666373

  • Allometric scaling of mortality rates with body mass in abalones OECOLOGIA Rossetto, M., De Leo, G. A., Bevacqua, D., Micheli, F. 2012; 168 (4): 989-996


    The existence of an allometric relationship between mortality rates and body mass has been theorized and extensively documented across taxa. Within species, however, the allometry between mortality rates and body mass has received substantially less attention and the consistency of such scaling patterns at the intra-specific level is controversial. We reviewed 73 experimental studies to examine the relationship between mortality rates and body size among seven species of abalone (Haliotis spp.), a marine herbivorous mollusk. Both in the field and in the laboratory, log-transformed mortality rates were negatively correlated with log-transformed individual body mass for all species considered, with allometric exponents remarkably similar among species. This regular pattern confirms previous findings that juvenile abalones suffer higher mortality rates than adult individuals. Field mortality rates were higher overall than those measured in the laboratory, and the relationship between mortality and body mass tended to be steeper in field than in laboratory conditions for all species considered. These results suggest that in the natural environment, additional mortality factors, especially linked to predation, could significantly contribute to mortality, particularly at small body sizes. On the other hand, the consistent allometry of mortality rates versus body mass in laboratory conditions suggests that other sources of mortality, beside predation, are size-dependent in abalone.

    View details for DOI 10.1007/s00442-011-2163-1

    View details for Web of Science ID 000301604200010

    View details for PubMedID 22020817

  • Consequences of extreme events on population persistence and evolution of a quantitative trait ECOLOGICAL INFORMATICS Vincenzi, S., De Leo, G. A., Bellingeri, M. 2012; 8: 20-28
  • Dispersal Patterns of Coastal Fish: Implications for Designing Networks of Marine Protected Areas PLOS ONE Di Franco, A., Gillanders, B. M., De Benedetto, G., Pennetta, A., De Leo, G. A., Guidetti, P. 2012; 7 (2)


    Information about dispersal scales of fish at various life history stages is critical for successful design of networks of marine protected areas, but is lacking for most species and regions. Otolith chemistry provides an opportunity to investigate dispersal patterns at a number of life history stages. Our aim was to assess patterns of larval and post-settlement (i.e. between settlement and recruitment) dispersal at two different spatial scales in a Mediterranean coastal fish (i.e. white sea bream, Diplodus sargus sargus) using otolith chemistry. At a large spatial scale (∼200 km) we investigated natal origin of fish and at a smaller scale (∼30 km) we assessed "site fidelity" (i.e. post-settlement dispersal until recruitment). Larvae dispersed from three spawning areas, and a single spawning area supplied post-settlers (proxy of larval supply) to sites spread from 100 to 200 km of coastline. Post-settlement dispersal occurred within the scale examined of ∼30 km, although about a third of post-settlers were recruits in the same sites where they settled. Connectivity was recorded both from a MPA to unprotected areas and vice versa. The approach adopted in the present study provides some of the first quantitative evidence of dispersal at both larval and post-settlement stages of a key species in Mediterranean rocky reefs. Similar data taken from a number of species are needed to effectively design both single marine protected areas and networks of marine protected areas.

    View details for DOI 10.1371/journal.pone.0031681

    View details for Web of Science ID 000302741300088

    View details for PubMedID 22355388

  • Getting a free ride on poultry farms: how highly pathogenic avian influenza may persist in spite of its virulence THEORETICAL ECOLOGY De Leo, G. A., Bolzoni, L. 2012; 5 (1): 23-35
  • Integrating habitat restoration and fisheries management: A small-scale case-study to support EEL conservation at the global scale KNOWLEDGE AND MANAGEMENT OF AQUATIC ECOSYSTEMS Ciccotti, E., Leone, C., Bevacqua, D., De Leo, G., Tancioni, L., Capoccioni, F. 2012
  • The Effect of Recurrent Floods on Genetic Composition of Marble Trout Populations PLOS ONE Pujolar, J. M., Vincenzi, S., Zane, L., Jesensek, D., De Leo, G. A., Crivelli, A. J. 2011; 6 (9)


    A changing global climate can threaten the diversity of species and ecosystems. We explore the consequences of catastrophic disturbances in determining the evolutionary and demographic histories of secluded marble trout populations in Slovenian streams subjected to weather extremes, in particular recurrent flash floods and debris flows causing massive mortalities. Using microsatellite data, a pattern of extreme genetic differentiation was found among populations (global F(ST) of 0.716), which exceeds the highest values reported in freshwater fish. All locations showed low levels of genetic diversity as evidenced by low heterozygosities and a mean of only 2 alleles per locus, with few or no rare alleles. Many loci showed a discontinuous allele distribution, with missing alleles across the allele size range, suggestive of a population contraction. Accordingly, bottleneck episodes were inferred for all samples with a reduction in population size of 3-4 orders of magnitude. The reduced level of genetic diversity observed in all populations implies a strong impact of genetic drift, and suggests that along with limited gene flow, genetic differentiation might have been exacerbated by recurrent mortalities likely caused by flash flood and debris flows. Due to its low evolutionary potential the species might fail to cope with an intensification and altered frequency of flash flood events predicted to occur with climate change.

    View details for DOI 10.1371/journal.pone.0023822

    View details for Web of Science ID 000294802800009

    View details for PubMedID 21931617

  • Density-dependent and inter-specific interactions affecting European eel settlement in freshwater habitats HYDROBIOLOGIA Bevacqua, D., Andrello, M., Melia, P., Vincenzi, S., De Leo, G. A., Crivelli, A. J. 2011; 671 (1): 259-265
  • An integrated genetic- demographic model to unravel the origin of genetic structure in European eel (Anguilla anguilla L.) EVOLUTIONARY APPLICATIONS Andrello, M., Bevacqua, D., Maes, G. E., De Leo, G. A. 2011; 4 (4): 517-533
  • No apparent genetic bottleneck in the demographically declining European eel using molecular genetics and forward-time simulations CONSERVATION GENETICS Pujolar, J. M., Bevacqua, D., Capoccioni, F., Ciccotti, E., De Leo, G. A., Zane, L. 2011; 12 (3): 813-825
  • Use of Anguilla anguilla for Biomonitoring Persistent Organic Pollutants (POPs) in Brackish and Riverine Waters in Central and Southern Italy WATER AIR AND SOIL POLLUTION Bettinetti, R., Galassi, S., Quadroni, S., Volta, P., Capoccioni, F., Ciccotti, E., De Leo, G. A. 2011; 217 (1-4): 321-331
  • Application of a Random Forest algorithm to predict spatial distribution of the potential yield of Ruditapes philippinarum in the Venice lagoon, Italy ECOLOGICAL MODELLING Vincenzi, S., Zucchetta, M., Franzoi, P., Pellizzato, M., Pranovi, F., De Leo, G. A., Torricelli, P. 2011; 222 (8): 1471-1478
  • Body growth and mortality of the spiny lobster Palinurus elephas within and outside a small marine protected area (vol 106, pg 543, 2010) FISHERIES RESEARCH Bevacqua, D., Melia, P., Follesa, M. C., De Leo, G. A., Gatto, M., Cau, A. 2011; 108 (2-3): 404-404
  • Genetic patchiness in European eel adults evidenced by molecular genetics and population dynamics modelling MOLECULAR PHYLOGENETICS AND EVOLUTION Pujolar, J. M., Bevacqua, D., Andrello, M., Capoccioni, F., Ciccotti, E., De Leo, G. A., Zane, L. 2011; 58 (2): 198-206


    Disentangling the demographic processes that determine the genetic structure of a given species is a fundamental question in conservation and management. In the present study, the population structure of the European eel was examined with a multidisciplinary approach combining the fields of molecular genetics and population dynamics modelling. First, we analyzed a total of 346 adult specimens of known age collected in three separate sample sites using a large panel of 22 EST-linked microsatellite loci. Second, we developed a European eel-specific model to unravel the demographic mechanisms that can produce the level of genetic differentiation estimated by molecular markers. This is the first study that reveals a pattern of genetic patchiness in maturing adults of the European eel. A highly significant genetic differentiation was observed among samples that did not follow an Isolation-by-Distance or Isolation-by-Time pattern. The observation of genetic patchiness in adults is likely to result from a limited parental contribution to each spawning event as suggested by our modelling approach. The value of genetic differentiation found is predicted by the model when reproduction occurs in a limited number of spawning events isolated from each other in time or space, with an average of 130-375 breeders in each spawning event. Unpredictability in spawning success may have important consequences for the life-history evolution of the European eel, including a bet-hedging strategy (distributing reproductive efforts over time) which could in turn guarantee successful reproduction of some adults.

    View details for DOI 10.1016/j.ympev.2010.11.019

    View details for Web of Science ID 000287888700006

    View details for PubMedID 21129491

  • Intra-specific scaling of natural mortality in fish: the paradigmatic case of the European eel OECOLOGIA Bevacqua, D., Melia, P., De Leo, G. A., Gatto, M. 2011; 165 (2): 333-339


    Identifying factors and processes influencing natural mortality is fundamental to the understanding of population dynamics. Metabolic theory of ecology and experimental studies at the cross-species level suggest the existence of general patterns linking natural mortality to body mass and temperature. However, there is scant evidence that similar relationships also hold at the intra-specific scale, possibly because of the relatively narrow range of sizes and temperatures experienced by most species and the effect of local adaptation, which can obscure links between temperature and vital rates. In this sense, the European eel Anguilla anguilla, a panmictic species with a wide distribution range, provides a paradigmatic case. We compiled data published in the past 30 years on eel mortality during the continental phase of the life cycle for 15 eel stocks and calibrated a general model for mortality, considering the effects of body mass, temperature, stock density and gender. Estimated activation energy (E = 1.2 eV) was at the upper extreme reported for metabolic reactions. Estimated mortality rates (ranging between 0.02 year(-1) at 8°C, low density and 0.47 year(-1) at 18°C, high density for a body mass of 100 g) were appreciably lower than those of most fishes, most likely due to the exceptionally low energy-consuming metabolism of eel.

    View details for DOI 10.1007/s00442-010-1727-9

    View details for Web of Science ID 000286224900008

    View details for PubMedID 20665048

  • Innocent until proven guilty? Stable coexistence of alien rainbow trout and native marble trout in a Slovenian stream NATURWISSENSCHAFTEN Vincenzi, S., Crivelli, A. J., Jesensek, D., Rossi, G., De Leo, G. A. 2011; 98 (1): 57-66


    To understand the consequences of the invasion of the nonnative rainbow trout Oncorhynchus mykiss on the native marble trout Salmo marmoratus, we compared two distinct headwater sectors where marble trout occur in allopatry (MTa) or sympatry (MTs) with rainbow trout (RTs) in the Idrijca River (Slovenia). Using data from field surveys from 2002 to 2009, with biannual (June and September) sampling and tagging from June 2004 onwards, we analyzed body growth and survival probabilities of marble trout in each stream sector. Density of age-0 in September over the study period was greater for MTs than MTa and very similar between MTs and RTs, while density of trout ≥age-1 was similar for MTa and MTs and greater than density of RTs. Monthly apparent survival probabilities were slightly higher in MTa than in MTs, while RTs showed a lower survival than MTs. Mean weight of marble and rainbow trout aged 0+ in September was negatively related to cohort density for both marble and rainbow trout, but the relationship was not significantly different between MTs and MTa. No clear depression of body growth of sympatric marble trout between sampling intervals was observed. Despite a later emergence, mean weight of RTs cohorts at age 0+ in September was significantly higher than weight of both MTs and MTa. The establishment of a self-sustaining population of rainbow trout does not have a significant impact on body growth and survival probabilities of sympatric marble trout. The numerical dominance of rainbow trout in streams at lower altitudes seem to suggest that while the low summer flow pattern of Slovenian streams is favorable for rainbow trout invasion, the adaptation of marble trout to headwater environments may limit the invasion success of rainbow trout in headwaters.

    View details for DOI 10.1007/s00114-010-0741-4

    View details for Web of Science ID 000286114800008

    View details for PubMedID 21088818

  • Body growth and mortality of the spiny lobster Palinurus elephas within and outside a small marine protected area FISHERIES RESEARCH Bevacqua, D., Melia, P., Follesa, M. C., De Leo, G. A., Gatto, M., Cau, A. 2010; 106 (3): 543-549
  • The value of spatial information in MPA network design PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Costello, C., Rassweiler, A., Siegel, D., De Leo, G., Micheli, F., Rosenberg, A. 2010; 107 (43): 18294-18299


    The science of spatial fisheries management, which combines ecology, oceanography, and economics, has matured significantly. As a result, there have been recent advances in exploiting spatially explicit data to develop spatially explicit management policies, such as networks of marine protected areas (MPAs). However, when data are sparse, spatially explicit policies become less viable, and we must instead rely on blunt policies such as total allowable catches or imprecisely configured networks of MPAs. Therefore, spatial information has the potential to change management approaches and thus has value. We develop a general framework within which to analyze the value of information for spatial fisheries management and apply that framework to several US Pacific coast fisheries. We find that improved spatial information can increase fishery value significantly (>10% in our simulations), and that it changes dramatically the efficient management approach-switching from diffuse effort everywhere to a strategy where fishing is spatially targeted, with some areas under intensive harvest and others closed to fishing. Using all available information, even when incomplete, is essential to management success and may as much as double fishery value relative to using (admittedly incorrect) assumptions commonly invoked.

    View details for DOI 10.1073/pnas.0908057107

    View details for Web of Science ID 000283677400016

    View details for PubMedID 20176962

  • Detection of density-dependent growth at two spatial scales in marble trout (Salmo marmoratus) populations ECOLOGY OF FRESHWATER FISH Vincenzi, S., Crivelli, A. J., Jesensek, D., De Leo, G. A. 2010; 19 (3): 338-347
  • Individual growth and its implications for the recruitment dynamics of stream-dwelling marble trout (Salmo marmoratus) ECOLOGY OF FRESHWATER FISH Vincenzi, S., Crivelli, A. J., Jesensek, D., De Leo, G. A. 2010; 19 (3): 477-486
  • The management of small, isolated salmonid populations: do we have to fix it if it ain't broken? ANIMAL CONSERVATION Vincenzi, S., Crivelli, A. J., Jesensek, D., De Leo, G. A. 2010; 13 (1): 21-23
  • Genetic variability is unrelated to growth and parasite infestation in natural populations of the European eel (Anguilla anguilla) MOLECULAR ECOLOGY Pujolar, J. M., Bevacqua, D., Capoccioni, F., Ciccotti, E., De Leo, G. A., Zane, L. 2009; 18 (22): 4604-4616


    Positive correlations between individual genetic heterozygosity and fitness-related traits (HFCs) have been observed in organisms as diverse as plants, marine bivalves, fish or mammals. HFCs are not universal and the strength and stability of HFCs seem to be variable across species, populations and ages. We analysed the relationship between individual genetic variability and two different estimators of fitness in natural samples of European eel, growth rate (using back-calculated length-at-age 1, 2 and 3) and parasite infestation by the swimbladder nematode Anguillicola crassus. Despite using a large data set of 22 expressed sequence tags-derived microsatellite loci and a large sample size of 346 individuals, no heterozygote advantage was observed in terms of growth rate or parasite load. The lack of association was evidenced by (i) nonsignificant global HFCs, (ii) a Multivariate General Linear Model showing no effect of heterozygosity on fitness components, (iii) single-locus analysis showing a lower number of significant tests than the expected false discovery rate, (iv) sign tests showing only a significant departure from expectations at one component, and, (v) a random distribution of significant single-locus HFCs that was not consistent across fitness components or sampling sites. This contrasts with the positive association observed in farmed eels in a previous study using allozymes, which can be explained by the nature of the markers used, with the allozyme study including many loci involved in metabolic energy pathways, while the expressed sequence tags-linked microsatellites might be located in genes or in the proximity of genes uncoupled with metabolism/growth.

    View details for DOI 10.1111/j.1365-294X.2009.04390.x

    View details for Web of Science ID 000271468800011

    View details for PubMedID 19840264

  • Genetic composition of Atlantic and Mediterranean recruits of European eel Anguilla anguilla based on EST-linked microsatellite loci JOURNAL OF FISH BIOLOGY Pujolar, J. M., De Leo, G. A., Ciccotti, E., Zane, L. 2009; 74 (9): 2034-2046


    Anguilla anguilla glass eels arriving at two Mediterranean and two Atlantic sites were tested for differences in genetic composition between regions using a total of 23 microsatellite loci developed from an expressed sequence tag (EST) library. Hierarchical analysis of molecular variance indicated a non-significant difference between regions (Mediterranean v. Atlantic), which contrasted with the significant differences observed between samples within regions. The existence of a single spawning site for all A. anguilla individuals and extensive migration loop with great opportunity for mixing of individuals might explain the homogeneity in genetic composition found between regions. The observation of a (small-scale) pattern of genetic patchiness among intra-annual samples (arrival waves) within geographic regions does not conflict with the lack of (large-scale) geographic sub-structuring found between the Mediterranean and Atlantic regions, but most likely is a consequence of the strong dependence of A. anguilla on oceanic conditions in the Sargasso Sea that might result in a limited parental contribution to each spawning event. The comparison of Atlantic and Mediterranean A. anguilla glass eel recruits based on EST-linked microsatellite loci provides evidence supporting the hypothesis of panmixia A. anguilla across Europe.

    View details for DOI 10.1111/j.1095-8649.2009.02267.x

    View details for Web of Science ID 000268271100014

    View details for PubMedID 20735687

  • Size selectivity of fyke nets for European eel Anguilla anguilla JOURNAL OF FISH BIOLOGY Bevacqua, D., De Leo, G. A., Gatto, M., Melia, P. 2009; 74 (9): 2178-2186


    Size selectivity of fyke nets for European eels Anguilla anguilla was investigated by reviewing the results of published experimental studies. A general size selectivity model was then derived that can be easily incorporated into demographic models to simulate population dynamics, assess and monitor abundance and length structure of eel stocks and forecast the consequences of different management options.

    View details for DOI 10.1111/j.1095-8649.2009.02243.x

    View details for Web of Science ID 000268271100023

    View details for PubMedID 20735696

  • Assessing Management Plans for the Recovery of the European Eel: A Need for Multi-Objective Analyses International Symposium on Challenges for Diadromous Fishes in a Dynamic Global Environment Bevacqua, D., Melia, P., Crivelli, A. J., Gatto, M., De Leo, G. A. AMER FISHERIES SOC. 2009: 637–647
  • Allometric Scaling and Seasonality in the Epidemics of Wildlife Diseases AMERICAN NATURALIST Bolzoni, L., Dobson, A. P., Gatto, M., De Leo, G. A. 2008; 172 (6): 818-828


    We present a susceptibles-exposed-infectives (SEI) model to analyze the effects of seasonality on epidemics, mainly of rabies, in a wide range of wildlife species. Model parameters are cast as simple allometric functions of host body size. Via nonlinear analysis, we investigate the dynamical behavior of the disease for different levels of seasonality in the transmission rate and for different values of the pathogen basic reproduction number (R(0)) over a broad range of body sizes. While the unforced SEI model exhibits long-term epizootic cycles only for large values of R(0), the seasonal model exhibits multiyear periodicity for small values of R(0). The oscillation period predicted by the seasonal model is consistent with those observed in the field for different host species. These conclusions are not affected by alternative assumptions for the shape of seasonality or for the parameters that exhibit seasonal variations. However, the introduction of host immunity (which occurs for rabies in some species and is typical of many other wildlife diseases) significantly modifies the epidemic dynamics; in this case, multiyear cycling requires a large level of seasonal forcing. Our analysis suggests that the explicit inclusion of periodic forcing in models of wildlife disease may be crucial to correctly describe the epidemics of wildlife that live in strongly seasonal environments.

    View details for DOI 10.1086/593000

    View details for Web of Science ID 000261235500011

    View details for PubMedID 18947297

  • Total population density during the first year of life as a major determinant of lifetime body-length trajectory in marble trout ECOLOGY OF FRESHWATER FISH Vincenzi, S., Crivelli, A. J., Jesensek, D., De Leo, G. A. 2008; 17 (4): 515-519
  • Parasites in food webs: the ultimate missing links ECOLOGY LETTERS Lafferty, K. D., Allesina, S., Arim, M., Briggs, C. J., De Leo, G., Dobson, A. P., Dunne, J. A., Johnson, P. T., Kuris, A. M., Marcogliese, D. J., Martinez, N. D., Memmott, J., Marquet, P. A., McLaughlin, J. P., Mordecai, E. A., Pascual, M., Poulin, R., Thieltges, D. W. 2008; 11 (6): 533-546


    Parasitism is the most common consumer strategy among organisms, yet only recently has there been a call for the inclusion of infectious disease agents in food webs. The value of this effort hinges on whether parasites affect food-web properties. Increasing evidence suggests that parasites have the potential to uniquely alter food-web topology in terms of chain length, connectance and robustness. In addition, parasites might affect food-web stability, interaction strength and energy flow. Food-web structure also affects infectious disease dynamics because parasites depend on the ecological networks in which they live. Empirically, incorporating parasites into food webs is straightforward. We may start with existing food webs and add parasites as nodes, or we may try to build food webs around systems for which we already have a good understanding of infectious processes. In the future, perhaps researchers will add parasites while they construct food webs. Less clear is how food-web theory can accommodate parasites. This is a deep and central problem in theoretical biology and applied mathematics. For instance, is representing parasites with complex life cycles as a single node equivalent to representing other species with ontogenetic niche shifts as a single node? Can parasitism fit into fundamental frameworks such as the niche model? Can we integrate infectious disease models into the emerging field of dynamic food-web modelling? Future progress will benefit from interdisciplinary collaborations between ecologists and infectious disease biologists.

    View details for DOI 10.1111/j.1461-0248.2008.01174.x

    View details for Web of Science ID 000255552100001

    View details for PubMedID 18462196

  • The role of density-dependent individual growth in the persistence of freshwater salmonid populations OECOLOGIA Vincenzi, S., Crivelli, A. J., Jesensek, D., De Leo, G. A. 2008; 156 (3): 523-534


    Theoretical and empirical models of populations dynamics have paid little attention to the implications of density-dependent individual growth on the persistence and regulation of small freshwater salmonid populations. We have therefore designed a study aimed at testing our hypothesis that density-dependent individual growth is a process that enhances population recovery and reduces extinction risk in salmonid populations in a variable environment subject to disturbance events. This hypothesis was tested in two newly introduced marble trout (Salmo marmoratus) populations living in Slovenian streams (Zakojska and Gorska) subject to severe autumn floods. We developed a discrete-time stochastic individual-based model of population dynamics for each population with demographic parameters and compensatory responses tightly calibrated on data from individually tagged marble trout. The occurrence of severe flood events causing population collapses was explicitly accounted for in the model. We used the model in a population viability analysis setting to estimate the quasi-extinction risk and demographic indexes of the two marble trout populations when individual growth was density-dependent. We ran a set of simulations in which the effect of floods on population abundance was explicitly accounted for and another set of simulations in which flood events were not included in the model. These simulation results were compared with those of scenarios in which individual growth was modelled with density-independent Von Bertalanffy growth curves. Our results show how density-dependent individual growth may confer remarkable resilience to marble trout populations in case of major flood events. The resilience to flood events shown by the simulation results can be explained by the increase in size-dependent fecundity as a consequence of the drop in population size after a severe flood, which allows the population to quickly recover to the pre-event conditions. Our results suggest that density-dependent individual growth plays a potentially powerful role in the persistence of freshwater salmonids living in streams subject to recurrent yet unpredictable flood events.

    View details for DOI 10.1007/s00442-008-1012-3

    View details for Web of Science ID 000255680000005

    View details for PubMedID 18386068

  • Body-size scaling in an SEI model of wildlife diseases THEORETICAL POPULATION BIOLOGY Bolzoni, L., De Leo, G. A., Gatto, M., Dobson, A. P. 2008; 73 (3): 374-382


    A number of wildlife pathogens are generalist and can affect different host species characterized by a wide range of body sizes. In this work we analyze the role of allometric scaling of host vital and epidemiological rates in a Susceptible-Exposed-Infected (SEI) model. Our analysis shows that the transmission coefficient threshold for the disease to establish in the population scales allometrically (exponent = 0.45) with host size as well as the threshold at which limit cycles occur. In contrast, the threshold of the basic reproduction number for sustained oscillations to occur is independent of the host size and is always greater than 5. In the case of rabies, we show that the oscillation periods predicted by the model match those observed in the field for a wide range of host sizes. The population dynamics of the SEI model is also analyzed in the case of pathogens affecting multiple coexisting hosts with different body sizes. Our analyses show that the basic reproduction number for limit cycles to occur depends on the ratio between host sizes, that the oscillation period in a multihost community is set by the smaller species dynamics, and that intermediate interspecific disease transmission can stabilize the epidemic occurrence in wildlife communities.

    View details for DOI 10.1016/j.tpb.2007.12.003

    View details for Web of Science ID 000255852500006

    View details for PubMedID 18241903

  • Potential factors controlling the population viability of newly introduced endangered marble trout populations BIOLOGICAL CONSERVATION Vincenzi, S., Crivelli, A. J., Jesensek, D., Rubin, J., Poizat, G., De Leo, G. A. 2008; 141 (1): 198-210
  • A cost analysis of alternative culling strategies for the eradication of classical swine fever in wildlife ENVIRONMENT AND DEVELOPMENT ECONOMICS Bolzoni, L., De Leo, G. A. 2007; 12: 653-671
  • Multi-objective assessment of conservation measures for the European eel (Anguilla anguilla): an application to the Camargue lagoons ICES Conference on Is There More to Eels than Slime Bevacqua, D., Melia, P., Crivelli, A. J., Gatto, M., De Leo, G. A. OXFORD UNIV PRESS. 2007: 1483–90
  • Transmission Heterogeneity and Control Strategies for Infectious Disease Emergence PLOS ONE Bolzoni, L., Real, L., De Leo, G. 2007; 2 (8)


    The control of emergence and spread of infectious diseases depends critically on the details of the genetic makeup of pathogens and hosts, their immunological, behavioral and ecological traits, and the pattern of temporal and spatial contacts among the age/stage-classes of susceptible and infectious host individuals.We show that failing to acknowledge the existence of heterogeneities in the transmission rate among age/stage-classes can make traditional eradication and control strategies ineffective, and in some cases, policies aimed at controlling pathogen emergence can even increase disease incidence in the host. When control strategies target for reduction in numbers those subsets of the population that effectively limit the production of new susceptible individuals, then control can produce a flush of new susceptibles entering the population. The availability of a new cohort of susceptibles may actually increase disease incidence. We illustrate these general points using Classical Swine Fever as a reference disease.Negative effects of culling are robust to alternative formulations of epidemiological processes and underline the importance of better assessing transmission structure in the design of wildlife disease control strategies.

    View details for DOI 10.1371/journal.pone.0000747

    View details for Web of Science ID 000207455300003

    View details for PubMedID 17712403

  • Early survival of marble trout Salmo marmoratus: evidence for density dependence? ECOLOGY OF FRESHWATER FISH Vincenzi, S., Crivelli, A. J., Jesensek, D., Rubin, J., De Leo, G. A. 2007; 16 (2): 116-123
  • Density-dependent individual growth of marble trout (Salmo marmoratus) in the Soca and Idrijca river basins, Slovenia HYDROBIOLOGIA Vincenzi, S., Crivelli, A. J., Jesensek, D., Rubin, J., De Leo, G. A. 2007; 583: 57-68
  • A comparative analysis of three habitat suitability models for commercial yield estimation of Tapes philippinarum in a North Adriatic coastal lagoon (Sacca di Goro, Italy) MARINE POLLUTION BULLETIN Vincenzi, S., Caramori, G., Rossi, R., De Leo, G. A. 2007; 55 (10-12): 579-590


    Habitat Suitability (HS) models have been extensively used by conservation planners to estimate the spatial distribution of threatened species and of species of commercial interest. In this work we compare three HS models for the estimation of commercial yield potential and the identification of suitable sites for Tapes philippinarum rearing in the Sacca di Goro lagoon (Italy) on the basis of six environmental factors. The habitat suitability index (HSI) is based on expert opinion while the habitat suitability conditional (HSC) is calibrated on observational data. The habitat suitability mixed (HSM) model is a two-part model combining expert knowledge and regression analysis: the first component of the model uses logistic regression to identify the areas in which clams are likely to be present; the second part applies the same parameter-specific suitability functions of the HSI model only in the areas previously identified as productive by the logistic component. The HS models were validated on an independent data set and estimates of potential yield of the Goro lagoon were compared. The effectiveness of the three approaches is then discussed in terms of predicted yield and identification of suitable sites for farming.

    View details for DOI 10.1016/j.marpolbul.2007.09.016

    View details for Web of Science ID 000252169600017

    View details for PubMedID 17963792

  • Estimating clam yield potential in the Sacca di Goro lagoon (Italy) by using a two-part conditional model AQUACULTURE Vincenzi, S., Caramori, G., Rossi, R., De Leo, G. A. 2006; 261 (4): 1281-1291
  • A simulation model of population genetic to unravel the panmictic nature of European eel Andrello, M., Bevacqua, D., De Leo, G. A., Piovani, P., Melia, P., Crivelli, A. J., Gatto, M. WILEY-BLACKWELL. 2006: 242–242
  • Timing and rate of sexual maturation of European eel in brackish and freshwater environments Annual Symposium of the Fisheries-Society-of-the-British-Isles Bevacqua, D., Melia, P., Crivelli, A. J., De Leo, G. A., Gatto, M. WILEY-BLACKWELL. 2006: 200–208
  • A demographic model for the management of eel fisheries in the Camargue lagoons Bevacqua, D., Melia, P., Crivelli, A. J., De Leo, G. A., Gatto, M. WILEY-BLACKWELL. 2006: 255–256
  • Sex differentiation of the European eel in brackish and freshwater environments: a comparative analysis JOURNAL OF FISH BIOLOGY Melia, P., Bevacqua, D., Crivelli, A. J., Panfili, J., De Leo, G. A., Gatto, M. 2006; 69 (4): 1228-1235
  • A GIS-based habitat suitability model for commercial yield estimation of Tapes philippinarum in a Mediterranean coastal lagoon (Sacca di Goro, Italy) 1st International Conference on Southern European Coastal Lagoons Vincenzi, S., Caramori, G., Rossi, R., De Leo, G. A. ELSEVIER SCIENCE BV. 2006: 90–104
  • Integrating marine protected areas with catch regulation CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES Hilborn, R., Micheli, F., De Leo, G. A. 2006; 63 (3): 642-649
  • Age and growth of Anguilla anguilla in the Camargue lagoons JOURNAL OF FISH BIOLOGY Melia, P., Bevacqua, D., Crivelli, A. J., De Leo, G. A., Panfili, J., Gatto, M. 2006; 68 (3): 876-890
  • A preliminary coastal wetland assessment procedure: Designing and testing an environmental sustainability index for Mediterranean lagoons Joint Scientific Meeting of the National-Inter-University-Consortium-for-Marine-Sciences/16th Congress of the Italian-Association-for-Oceanology-and-Limnology Carletti, A., De Leo, G. A., Ferrari, I. TAYLOR & FRANCIS LTD. 2006: 15–35
  • A critical review of representative wetland rapid assessment methods in North America AQUATIC CONSERVATION-MARINE AND FRESHWATER ECOSYSTEMS Carletti, A., De Leo, G. A., Ferrari, I. 2004; 14: S103-S113

    View details for DOI 10.1002/aqc.654

    View details for Web of Science ID 000225589300010

  • The decline of the grey partridge in Europe: comparing demographies in traditional and modern agricultural landscapes ECOLOGICAL MODELLING De Leo, G. A., Focardi, S., Gatto, M., Cattadori, I. M. 2004; 177 (3-4): 313-335
  • Density and temperature-dependence of vital rates in the Manila clam Tapes philippinarum: a stochastic demographic model MARINE ECOLOGY PROGRESS SERIES Melia, P., De Leo, G. A., Gatto, M. 2004; 272: 153-164
  • Carbon emissions - The economic benefits of the Kyoto Protocol NATURE De Leo, G. A., Rizzi, L., Caizzi, A., Gatto, M. 2001; 413 (6855): 478-479


    The third Conference of the Parties in Kyoto set the target of reducing greenhouse-gas emissions by an average of 5.3% with respect to 1990 values by 2008-2012. One of the main objections to the protocol's ratification is that compliance would pose an unbearable economic burden on the countries involved. But we show here that this is not the case if costs apart from the direct costs of energy production are also considered. Costs are also incurred in rectifying damage to human health, material goods, agriculture and the environment related to greenhouse-gas emissions.

    View details for Web of Science ID 000171340500034

    View details for PubMedID 11586347

  • A stochastic bioeconomic analysis of silver eel fisheries ECOLOGICAL APPLICATIONS De Leo, G. A., Gatto, M. 2001; 11 (1): 281-294
  • Pricing biodiversity and ecosystem services: The never-ending story BIOSCIENCE Gatto, M., De Leo, G. A. 2000; 50 (4): 347-355
  • VVF: integrating modelling and GIS in a software tool for habitat suitability assessment ENVIRONMENTAL MODELLING & SOFTWARE Ortigosa, G. R., De Leo, G. A., Gatto, M. 2000; 15 (1): 1-12
  • Interspecific competition among macroparasites in a density-dependent host population JOURNAL OF MATHEMATICAL BIOLOGY Gatto, M., De Leo, G. A. 1998; 37 (5): 467-490
  • Trends in vital rates of the European eel: Evidence for density dependence? ECOLOGICAL APPLICATIONS DELEO, G. A., Gatto, M. 1996; 6 (4): 1281-1294
  • Allometry and simple epidemic models for microparasites NATURE DELEO, G. A., Dobson, A. P. 1996; 379 (6567): 720-722


    Simple mathematical models for microparasites offer a useful way to examine the population dynamics of different viral and bacterial pathogens. One constraint in applying these models in free-living host populations is the paucity of data with which to estimate transmission rates. Here we recast a standard epidemiological model by setting the birth and death rates of the host population and its density as simple allometric functions of host body weight. We then use standard threshold theorems for the model in order to estimate the minimum rate of transmission for the parasite to establish itself in a mammalian host population. Transmission rates that produce different comparable values of the parasites' basic reproductive number, RO, are themselves allometric functions of host body size. We have extended the model to show that hosts having different body sizes suffer epidemic outbreaks whose frequency scales with body size. The expected epidemic periods for pathogens in different mammalian populations correspond to cycles observed in free-living populations.

    View details for Web of Science ID A1996TW56700050

    View details for PubMedID 8602216