30 results on '"Dobson, Andrew"'
Search Results
2. Pyrodiversity interacts with rainfall to increase bird and mammal richness in African savannas.
- Author
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Beale CM, Courtney Mustaphi CJ, Morrison TA, Archibald S, Anderson TM, Dobson AP, Donaldson JE, Hempson GP, Probert J, and Parr CL
- Subjects
- Animals, Fires, Grassland, Biodiversity, Birds, Mammals
- Abstract
Fire is a fundamental process in savannas and is widely used for management. Pyrodiversity, variation in local fire characteristics, has been proposed as a driver of biodiversity although empirical evidence is equivocal. Using a new measure of pyrodiversity (Hempson et al.), we undertook the first continent-wide assessment of how pyrodiversity affects biodiversity in protected areas across African savannas. The influence of pyrodiversity on bird and mammal species richness varied with rainfall: strongest support for a positive effect occurred in wet savannas (> 650 mm/year), where species richness increased by 27% for mammals and 40% for birds in the most pyrodiverse regions. Range-restricted birds were most increased by pyrodiversity, suggesting the diversity of fire regimes increases the availability of rare niches. Our findings are significant because they explain the conflicting results found in previous studies of savannas. We argue that managing savanna landscapes to increase pyrodiversity is especially important in wet savannas., (© 2018 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.)
- Published
- 2018
- Full Text
- View/download PDF
3. Null expectations for disease dynamics in shrinking habitat: dilution or amplification?
- Author
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Faust CL, Dobson AP, Gottdenker N, Bloomfield LSP, McCallum HI, Gillespie TR, Diuk-Wasser M, and Plowright RK
- Subjects
- Animals, Ecosystem, Humans, Biodiversity, Communicable Diseases transmission
- Abstract
As biodiversity declines with anthropogenic land-use change, it is increasingly important to understand how changing biodiversity affects infectious disease risk. The dilution effect hypothesis, which points to decreases in biodiversity as critical to an increase in infection risk, has received considerable attention due to the allure of a win-win scenario for conservation and human well-being. Yet some empirical data suggest that the dilution effect is not a generalizable phenomenon. We explore the response of pathogen transmission dynamics to changes in biodiversity that are driven by habitat loss using an allometrically scaled multi-host model. With this model, we show that declining habitat, and thus declining biodiversity, can lead to either increasing or decreasing infectious-disease risk, measured as endemic prevalence. Whether larger habitats, and thus greater biodiversity, lead to a decrease (dilution effect) or increase (amplification effect) in infection prevalence depends upon the pathogen transmission mode and how host competence scales with body size. Dilution effects were detected for most frequency-transmitted pathogens and amplification effects were detected for density-dependent pathogens. Amplification effects were also observed over a particular range of habitat loss in frequency-dependent pathogens when we assumed that host competence was greatest in large-bodied species. By contrast, only amplification effects were observed for density-dependent pathogens; host competency only affected the magnitude of the effect. These models can be used to guide future empirical studies of biodiversity-disease relationships across gradients of habitat loss. The type of transmission, the relationship between host competence and community assembly, the identity of hosts contributing to transmission, and how transmission scales with area are essential factors to consider when elucidating the mechanisms driving disease risk in shrinking habitat.This article is part of the themed issue 'Conservation, biodiversity and infectious disease: scientific evidence and policy implications'., (© 2017 The Author(s).)
- Published
- 2017
- Full Text
- View/download PDF
4. Epidemiological Implications of Host Biodiversity and Vector Biology: Key Insights from Simple Models.
- Author
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Dobson AD and Auld SK
- Subjects
- Animals, Feeding Behavior, Host-Parasite Interactions, Humans, Population Density, Zoonoses, Arachnid Vectors, Biodiversity, Culicidae physiology, Epidemiologic Factors, Insect Vectors, Models, Theoretical, Ticks physiology
- Abstract
Models used to investigate the relationship between biodiversity change and vector-borne disease risk often do not explicitly include the vector; they instead rely on a frequency-dependent transmission function to represent vector dynamics. However, differences between classes of vector (e.g., ticks and insects) can cause discrepancies in epidemiological responses to environmental change. Using a pair of disease models (mosquito- and tick-borne), we simulated substitutive and additive biodiversity change (where noncompetent hosts replaced or were added to competent hosts, respectively), while considering different relationships between vector and host densities. We found important differences between classes of vector, including an increased likelihood of amplified disease risk under additive biodiversity change in mosquito models, driven by higher vector biting rates. We also draw attention to more general phenomena, such as a negative relationship between initial infection prevalence in vectors and likelihood of dilution, and the potential for a rise in density of infected vectors to occur simultaneously with a decline in proportion of infected hosts. This has important implications; the density of infected vectors is the most valid metric for primarily zoonotic infections, while the proportion of infected hosts is more relevant for infections where humans are a primary host.
- Published
- 2016
- Full Text
- View/download PDF
5. Commentary on 'A Candide response to Panglossian accusations by Randolph and Dobson: biodiversity buffers disease' by Dr R. Ostfeld (Parasitology 2013, in press).
- Author
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Randolph SE and Dobson AD
- Subjects
- Animals, Humans, Biodiversity, Communicable Diseases, Parasitic Diseases
- Published
- 2013
- Full Text
- View/download PDF
6. Parasites affect food web structure primarily through increased diversity and complexity.
- Author
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Dunne JA, Lafferty KD, Dobson AP, Hechinger RF, Kuris AM, Martinez ND, McLaughlin JP, Mouritsen KN, Poulin R, Reise K, Stouffer DB, Thieltges DW, Williams RJ, and Zander CD
- Subjects
- Animals, Linear Models, Models, Biological, Probability, Species Specificity, Biodiversity, Food Chain, Parasites physiology
- Abstract
Comparative research on food web structure has revealed generalities in trophic organization, produced simple models, and allowed assessment of robustness to species loss. These studies have mostly focused on free-living species. Recent research has suggested that inclusion of parasites alters structure. We assess whether such changes in network structure result from unique roles and traits of parasites or from changes to diversity and complexity. We analyzed seven highly resolved food webs that include metazoan parasite data. Our analyses show that adding parasites usually increases link density and connectance (simple measures of complexity), particularly when including concomitant links (links from predators to parasites of their prey). However, we clarify prior claims that parasites "dominate" food web links. Although parasites can be involved in a majority of links, in most cases classic predation links outnumber classic parasitism links. Regarding network structure, observed changes in degree distributions, 14 commonly studied metrics, and link probabilities are consistent with scale-dependent changes in structure associated with changes in diversity and complexity. Parasite and free-living species thus have similar effects on these aspects of structure. However, two changes point to unique roles of parasites. First, adding parasites and concomitant links strongly alters the frequency of most motifs of interactions among three taxa, reflecting parasites' roles as resources for predators of their hosts, driven by trophic intimacy with their hosts. Second, compared to free-living consumers, many parasites' feeding niches appear broader and less contiguous, which may reflect complex life cycles and small body sizes. This study provides new insights about generic versus unique impacts of parasites on food web structure, extends the generality of food web theory, gives a more rigorous framework for assessing the impact of any species on trophic organization, identifies limitations of current food web models, and provides direction for future structural and dynamical models., Competing Interests: The authors have declared that no competing interests exist. Any use of trade, product or firm names in this publication is for descriptive purposes only and does not imply endorsement by the US government.
- Published
- 2013
- Full Text
- View/download PDF
7. Linking community and disease ecology: the impact of biodiversity on pathogen transmission.
- Author
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Roche B, Dobson AP, Guégan JF, and Rohani P
- Subjects
- Animals, Body Size, Empirical Research, Models, Biological, Population Dynamics, Public Health, Species Specificity, Zoonoses transmission, Biodiversity, Biota, Communicable Diseases, Emerging transmission, Disease Susceptibility, Ecosystem
- Abstract
The increasing number of zoonotic diseases spilling over from a range of wild animal species represents a particular concern for public health, especially in light of the current dramatic trend of biodiversity loss. To understand the ecology of these multi-host pathogens and their response to environmental degradation and species extinctions, it is necessary to develop a theoretical framework that takes into account realistic community assemblages. Here, we present a multi-host species epidemiological model that includes empirically determined patterns of diversity and composition derived from community ecology studies. We use this framework to study the interaction between wildlife diversity and directly transmitted pathogen dynamics. First, we demonstrate that variability in community composition does not affect significantly the intensity of pathogen transmission. We also show that the consequences of community diversity can differentially impact the prevalence of pathogens and the number of infectious individuals. Finally, we show that ecological interactions among host species have a weaker influence on pathogen circulation than inter-species transmission rates. We conclude that integration of a community perspective to study wildlife pathogens is crucial, especially in the context of understanding and predicting infectious disease emergence events.
- Published
- 2012
- Full Text
- View/download PDF
8. Disease invasion: impacts on biodiversity and human health.
- Author
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Cunningham AA, Dobson AP, and Hudson PJ
- Subjects
- Animals, Animals, Wild microbiology, Communicable Diseases, Emerging microbiology, Disease Reservoirs, Fungi pathogenicity, Humans, Biodiversity, Communicable Diseases, Emerging transmission, Global Health
- Abstract
An introduction to the theme issue that includes papers that identify how, where and why infectious diseases in wildlife emerge, while also addressing their possible conservation impacts.
- Published
- 2012
- Full Text
- View/download PDF
9. Bolder thinking for conservation.
- Author
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Noss RF, Dobson AP, Baldwin R, Beier P, Davis CR, Dellasala DA, Francis J, Locke H, Nowak K, Lopez R, Reining C, Trombulak SC, and Tabor G
- Subjects
- Conservation of Natural Resources economics, Public Opinion, Biodiversity, Conservation of Natural Resources trends
- Published
- 2012
- Full Text
- View/download PDF
10. Disease ecology, biodiversity, and the latitudinal gradient in income.
- Author
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Bonds MH, Dobson AP, and Keenan DC
- Subjects
- Animals, Cost of Illness, Disease Vectors, Geography, Humans, Models, Statistical, Biodiversity, Income, Parasitic Diseases economics, Parasitic Diseases epidemiology
- Abstract
While most of the world is thought to be on long-term economic growth paths, more than one-sixth of the world is roughly as poor today as their ancestors were hundreds of years ago. The majority of the extremely poor live in the tropics. The latitudinal gradient in income is highly suggestive of underlying biophysical drivers, of which disease conditions are an especially salient example. However, conclusions have been confounded by the simultaneous causality between income and disease, in addition to potentially spurious relationships. We use a simultaneous equations model to estimate the relative effects of vector-borne and parasitic diseases (VBPDs) and income on each other, controlling for other factors. Our statistical model indicates that VBPDs have systematically affected economic development, evident in contemporary levels of per capita income. The burden of VBDPs is, in turn, determined by underlying ecological conditions. In particular, the model predicts it to rise as biodiversity falls. Through these positive effects on human health, the model thus identifies measurable economic benefits of biodiversity., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2012
- Full Text
- View/download PDF
11. Impacts of biodiversity on the emergence and transmission of infectious diseases.
- Author
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Keesing F, Belden LK, Daszak P, Dobson A, Harvell CD, Holt RD, Hudson P, Jolles A, Jones KE, Mitchell CE, Myers SS, Bogich T, and Ostfeld RS
- Subjects
- Animals, Communicable Diseases epidemiology, Communicable Diseases microbiology, Communicable Diseases virology, Communicable Diseases, Emerging epidemiology, Communicable Diseases, Emerging microbiology, Communicable Diseases, Emerging transmission, Communicable Diseases, Emerging virology, Orthohantavirus physiology, Humans, Lyme Disease microbiology, Lyme Disease transmission, Species Specificity, Zoonoses epidemiology, Zoonoses transmission, Biodiversity, Communicable Diseases transmission
- Abstract
Current unprecedented declines in biodiversity reduce the ability of ecological communities to provide many fundamental ecosystem services. Here we evaluate evidence that reduced biodiversity affects the transmission of infectious diseases of humans, other animals and plants. In principle, loss of biodiversity could either increase or decrease disease transmission. However, mounting evidence indicates that biodiversity loss frequently increases disease transmission. In contrast, areas of naturally high biodiversity may serve as a source pool for new pathogens. Overall, despite many remaining questions, current evidence indicates that preserving intact ecosystems and their endemic biodiversity should generally reduce the prevalence of infectious diseases.
- Published
- 2010
- Full Text
- View/download PDF
12. Projected impacts of climate and land-use change on the global diversity of birds.
- Author
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Jetz W, Wilcove DS, and Dobson AP
- Subjects
- Animals, Forecasting, Geography, Greenhouse Effect, Population Dynamics, Biodiversity, Birds, Climate
- Abstract
Over the past few decades, land-use and climate change have led to substantial range contractions and species extinctions. Even more dramatic changes to global land cover are projected for this century. We used the Millennium Ecosystem Assessment scenarios to evaluate the exposure of all 8,750 land bird species to projected land-cover changes due to climate and land-use change. For this first baseline assessment, we assumed stationary geographic ranges that may overestimate actual losses in geographic range. Even under environmentally benign scenarios, at least 400 species are projected to suffer >50% range reductions by the year 2050 (over 900 by the year 2100). Although expected climate change effects at high latitudes are significant, species most at risk are predominantly narrow-ranged and endemic to the tropics, where projected range contractions are driven by anthropogenic land conversions. Most of these species are currently not recognized as imperiled. The causes, magnitude and geographic patterns of potential range loss vary across socioeconomic scenarios, but all scenarios (even the most environmentally benign ones) result in large declines of many species. Whereas climate change will severely affect biodiversity, in the near future, land-use change in tropical countries may lead to yet greater species loss. A vastly expanded reserve network in the tropics, coupled with more ambitious goals to reduce climate change, will be needed to minimize global extinctions.
- Published
- 2007
- Full Text
- View/download PDF
13. Ecology: The Convention on Biological Diversity's 2010 target.
- Author
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Balmford A, Bennun L, Brink BT, Cooper D, Côte IM, Crane P, Dobson A, Dudley N, Dutton I, Green RE, Gregory RD, Harrison J, Kennedy ET, Kremen C, Leader-Williams N, Lovejoy TE, Mace G, May R, Mayaux P, Morling P, Phillips J, Redford K, Ricketts TH, Rodríguez JP, Sanjayan M, Schei PJ, van Jaarsveld AS, and Walther BA
- Subjects
- Animals, Ecosystem, Humans, Interdisciplinary Communication, International Cooperation, Models, Biological, Models, Theoretical, Public Policy, Biodiversity, Conservation of Natural Resources, Ecology
- Published
- 2005
- Full Text
- View/download PDF
14. Introduction: Disease invasion: impacts on biodiversity and human health
- Author
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Cunningham, Andrew A., Dobson, Andrew P., and Hudson, Peter J.
- Published
- 2012
15. Habitat Loss, Trophic Collapse, and the Decline of Ecosystem Services
- Author
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Dobson, Andrew, Lodge, David, Alder, Jackie, Cumming, Graeme S., Keymer, Juan, McGlade, Jacquie, Mooney, Hal, Rusak, James A., Sala, Osvaldo, Wolters, Volkmar, Wall, Diana, Winfree, Rachel, and Xenopoulos, Marguerite A.
- Published
- 2006
16. Social Organization and Parasite Risk in Mammals: Integrating Theory and Empirical Studies
- Author
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Altizer, Sonia, Nunn, Charles L., Thrall, Peter H., Gittleman, John L., Antonovics, Janis, Cunningham, Andrew A., Cunnningham, Andrew A., Dobson, Andrew P., Ezenwa, Vanessa, Jones, Kate E., Pedersen, Amy B., Poss, Mary, and Pulliam, Juliet R. C.
- Published
- 2003
- Full Text
- View/download PDF
17. An inconvenient misconception: Climate change is not the principal driver of biodiversity loss.
- Author
-
Caro, Tim, Rowe, Zeke, Berger, Joel, Wholey, Philippa, and Dobson, Andrew
- Subjects
ENVIRONMENTAL degradation ,EFFECT of human beings on climate change ,HABITAT destruction ,HABITATS ,BIODIVERSITY ,AMPHIBIANS - Abstract
The current perception that climate change is the principal threat to biodiversity is at best premature. Although highly relevant, it detracts focus and effort from the primary threats: habitat destruction and overexploitation. We collated causes of vertebrate extinctions since 1900, threat information for amphibia, birds, and mammals from the IUCN Red List, and scrutinized others' attempts to compare climate change with commensurate anthropogenic threats. In each analysis, none of the arguments founded on climate change's wide‐ranging effects are as urgent for biodiversity as those for habitat loss and overexploitation. Present conservation efforts must refocus on these issues. Conserving ecosystems by focusing on these major threats not only protects biodiversity but is the only available, economically viable, global strategy to reverse climate change. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
18. The Convention on Biological Diversity's 2010 Target
- Author
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Balmford, Andrew, Bennun, Leon, Brink, Ben ten, Cooper, David, Côté, Isabelle M., Crane, Peter, Dobson, Andrew, Dudley, Nigel, Dutton, Ian, Green, Rhys E., Gregory, Richard D., Harrison, Jeremy, Kennedy, Elizabeth T., Kremen, Claire, Leader-Williams, Nigel, Lovejoy, Thomas E., Mace, Georgina, May, Robert, Mayaux, Phillipe, Morling, Paul, Phillips, Joanna, Redford, Kent, Ricketts, Taylor H., Rodríguez, Jon Paul, Sanjayan, M., Schei, Peter J., van Jaarsveld, Albert S., and Walther, Bruno A.
- Published
- 2005
19. Can We Defy Nature's End?
- Author
-
Pimm, Stuart L., Ayres, Márcio, Balmford, Andrew, Branch, George, Brandon, Katrina, Brooks, Thomas, Bustamante, Rodrigo, Costanza, Robert, Cowling, Richard, Curran, Lisa M., Dobson, Andrew, Farber, Stephen, Gascon, Claude, Kitching, Roger, McNeely, Jeffrey, Lovejoy, Thomas, Mittermeier, Russell A., Myers, Norman, Patz, Jonathan A., Raffle, Bradley, Rapport, David, Raven, Peter, Roberts, Callum, Rodríguez, Jon Paul, Rylands, Anthony B., Tucker, Compton, Safina, Carl, Samper, Cristián, Supriatna, Jatna, Wall, Diana H., and Wilcove, David
- Published
- 2001
20. Epidemiological Implications of Host Biodiversity and Vector Biology: Key Insights from Simple Models
- Author
-
Dobson, Andrew and Auld, Stuart
- Subjects
dilution effect ,tick-borne disease ,vector-borne disease ,disease risk ,biodiversity - Abstract
Models used to investigate the relationship between biodiversity change and vector-borne disease risk often do not explicitly include the vector; they instead rely on a frequency-dependent transmission function to represent vector dynamics. However, differences between classes of vector (e.g., ticks and insects) can cause discrepancies in epidemiological responses to environmental change. Using a pair of disease models (mosquito- and tick-borne), we simulated substitutive and additive biodiversity change (where noncompetent hosts replaced or were added to competent hosts, respectively), while considering different relationships between vector and host densities. We found important differences between classes of vector, including an increased likelihood of amplified disease risk under additive biodiversity change in mosquito models, driven by higher vector biting rates. We also draw attention to more general phenomena, such as a negative relationship between initial infection prevalence in vectors and likelihood of dilution, and the potential for a rise in density of infected vectors to occur simultaneously with a decline in proportion of infected hosts. This has important implications; the density of infected vectors is the most valid metric for primarily zoonotic infections, while the proportion of infected hosts is more relevant for infections where humans are a primary host.
- Published
- 2016
21. Continent‐level drivers of African pyrodiversity.
- Author
-
Hempson, Gareth P., Parr, Catherine L., Archibald, Sally, Anderson, T. Michael, Mustaphi, Colin J. Courtney, Dobson, Andrew P., Donaldson, Jason E., Morrison, Thomas A., Probert, James, and Beale, Colin M.
- Subjects
BIODIVERSITY ,MODIS (Spectroradiometer) ,FIRES ,POPULATION density ,SPACETIME - Abstract
Pyrodiversity, which describes fire variability over space and time, is believed to increase habitat heterogeneity and thereby promote biodiversity. However, to date there is no standardised metric for quantifying pyrodiversity, and so broad geographic patterns and drivers of pyrodiversity remain unexplored. We present the first generalizable method to quantify pyrodiversity, and use it to address the fundamental questions of what drives pyrodiversity, which fire attributes constrain pyrodiversity under different conditions, and whether pyrodiversity is spatial grain‐dependent. We linked the MODIS burned area and active fire products to measure fire size, seasonal timing, return interval, and intensity for 2.2 million individual fires in sub‐Saharan Africa from 2000–2015. We then quantified pyrodiversity as a four‐dimensional hypervolume described by fire attributes within a grid cell, for any spatial grain of analysis. Environmental (rainfall, vegetation, soils, and topography) and human‐associated (cattle biomass, cropland area, and human population density) variables were assessed as potential drivers of pyrodiversity. Rainfall was the main environmental driver of pyrodiversity, with higher pyrodiversity in drier regions (< 650 mm yr
–1 ). Pyrodiversity was not strongly associated with human‐associated variables across Africa. Rainfall and a human influence index had clear but contrasting effects on the variability of fire size, seasonal timing, return interval, and intensity. Our analyses show that fire size and seasonal timing constrain pyrodiversity in wetter regions, whereas none of the fire attributes pose a strong constraint in drier regions. We found no evidence that pyrodiversity was spatial grain‐dependent when recalculated at 5‐minute grain increments from 15 to 120 minutes. We hypothesise that the strongest positive effect of pyrodiversity on biodiversity in all its forms will occur at intermediate precipitation (650–1300 mm yr–1 ), where fire plays an important role in shaping vegetation structure and where pyrodiversity is still quite high. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
22. Pangloss revisited: A critique of the dilution effect and the biodiversity-buffers-disease paradigm
- Author
-
Randolph, Sarah E and Dobson, Andrew
- Subjects
helminths ,vector-borne diseases ,dilution effect ,rodent-borne infections ,community structure ,disease risk ,biodiversity - Abstract
The twin concepts of zooprophylaxis and the dilution effect originated with vector-borne diseases (malaria), were driven forward by studies on Lyme borreliosis and have now developed into the mantra "biodiversity protects against disease". The basic idea is that by diluting the assemblage of transmission-competent hosts with non-competent hosts, the probability of vectors feeding on transmission-competent hosts is reduced and so the abundance of infected vectors is lowered. The same principle has recently been applied to other infectious disease systems - tick-borne, insect-borne, indirectly transmitted via intermediate hosts, directly transmitted. It is claimed that the presence of extra species of various sorts, acting through a variety of distinct mechanisms, causes the prevalence of infectious agents to decrease. Examination of the theoretical and empirical evidence for this hypothesis reveals that it applies only in certain circumstances even amongst tick-borne diseases, and even less often if considering the correct metric - abundance rather than prevalence of infected vectors. Whether dilution or amplification occurs depends more on specific community composition than on biodiversity per se. We warn against raising a straw man, an untenable argument easily dismantled and dismissed. The intrinsic value of protecting biodiversity and ecosystem function outweighs this questionable utilitarian justification.
- Published
- 2012
23. Predicted Impact of Barriers to Migration on the Serengeti Wildebeest Population.
- Author
-
Holdo, Ricardo M., Fryxell, John M., Sinclair, Anthony R. E., Dobson, Andrew, and Holt, Robert D.
- Subjects
EMIGRATION & immigration ,HABITATS ,ECOLOGY ,SIMULATION methods & models ,ANALYTICAL mechanics ,BIODIVERSITY ,FRAGMENTED landscapes ,ECOSYSTEM health ,BIOLOGY - Abstract
The Serengeti wildebeest migration is a rare and spectacular example of a once-common biological phenomenon. A proposed road project threatens to bisect the Serengeti ecosystem and its integrity. The precautionary principle dictates that we consider the possible consequences of a road completely disrupting the migration. We used an existing spatially-explicit simulation model of wildebeest movement and population dynamics to explore how placing a barrier to migration across the proposed route (thus creating two disjoint but mobile subpopulations) might affect the long-term size of the wildebeest population. Our simulation results suggest that a barrier to migration—even without causing habitat loss—could cause the wildebeest population to decline by about a third. The driver of this decline is the effect of habitat fragmentation (even without habitat loss) on the ability of wildebeest to effectively track temporal shifts in high-quality forage resources across the landscape. Given the important role of the wildebeest migration for a number of key ecological processes, these findings have potentially important ramifications for ecosystem biodiversity, structure, and function in the Serengeti. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
24. Pathogen-induced reversal of native dominance in a grassland community.
- Author
-
Borer, Elizabeth T., Hosseini, Parviez R., Seabloom, Eric W., and Dobson, Andrew P.
- Subjects
PLANT diseases ,PLANT invasions ,BACTERIAL diseases of plants ,PLANT-pathogen relationships ,PHYTOPATHOGENIC microorganisms ,INTRODUCED animals ,INVASIVE plants ,BIODIVERSITY - Abstract
Disease may play a critical role in invasions by nonnative plants and animals that currently threaten global biodiversity. For example, a generalist viral pathogen has been recently implicated in one of the most extensive plant invasions worldwide, the invasion and domination of California's perennial grasslands by exotic annual grasses. To date, disease has never been quantitatively assessed as a cause of this invasion. Using a model with field-estimated parameters, we demonstrate that pathogen presence was necessary to reverse competitive outcome and to allow exotic annual grass invasion and dominance. Although pathogen-induced reversal of a competitive hierarchy has been suggested as a mechanism of species invasion, here we quantitatively demonstrate the importance of this phenomenon by using field-derived parameters in a dynamical model. Pathogen-mediated reversals in competitive balance may be critically important for understanding past, and predicting future, invasions. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
25. Is a healthy ecosystem one that is rich in parasites?
- Author
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Hudson, Peter J., Dobson, Andrew P., and Lafferty, Kevin D.
- Subjects
- *
PARASITES , *BIOTIC communities , *BIOMASS , *BIODIVERSITY - Abstract
Historically, the role of parasites in ecosystem functioning has been considered trivial because a cursory examination reveals that their relative biomass is low compared with that of other trophic groups. However there is increasing evidence that parasite-mediated effects could be significant: they shape host population dynamics, alter interspecific competition, influence energy flow and appear to be important drivers of biodiversity. Indeed they influence a range of ecosystem functions and have a major effect on the structure of some food webs. Here, we consider the bottom-up and top-down processes of how parasitism influences ecosystem functioning and show that there is evidence that parasites are important for biodiversity and production; thus, we consider a healthy system to be one that is rich in parasite species. [Copyright &y& Elsevier]
- Published
- 2006
- Full Text
- View/download PDF
26. Population Dynamics of Pathogens with Multiple Host Species.
- Author
-
Dobson, Andrew
- Subjects
- *
PATHOGENIC microorganisms , *SPECIES diversity , *BIODIVERSITY , *EPIDEMICS , *MICROORGANISMS , *EPIDEMIOLOGY - Abstract
Pathogens that can infect multiple host species will have different dynamics than pathogens that are restricted to a single species of host. This article examines the conditions for establishment and long-term population dynamic behavior of pathogens that infect multiple species of hosts. The article attempts to address three major questions in this area: First, under which conditions will increases in the diversity of host species buffer infectious disease outbreaks, and under which conditions will host diversity amplify disease outbreaks? Second, under what conditions is it possible to control an infectious agent by focusing control against only one host species? Third, what role does host species diversity play in maintaining pathogen persistence? The answers to these questions supply some important general insights into the role that biodiversity plays in buffering humans and other species against new and emerging pathogens. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
27. SYNOPTIC TINKERING: INTEGRATING STRATEGIES FOR LARGE-SCALE CONSERVATION.
- Author
-
Dobson, Andrew P., Rodríguez, Jon Paul, and Roberts, W. Mark
- Subjects
BIODIVERSITY ,SPECIES ,ANTHROPOGENIC effects on nature ,HABITATS - Abstract
The article presents the study on the strategies that will protect biodiversity of species in the U.S. It states that the observed distribution of endangered species reflects modification of underlying pattern of biodiversity by anthropogenic activities. It notes the need of a mixture of strategies to protect the species and their habitats. It mentions that conserving biodiversity requires greater focus.
- Published
- 2001
- Full Text
- View/download PDF
28. Compromise solutions between conservation and road building in the tropics.
- Author
-
Caro, Tim, Dobson, Andrew, Marshall, Andrew J., and Peres, Carlos A.
- Subjects
- *
ROAD construction , *WILDERNESS areas , *PROTECTED areas , *BIODIVERSITY , *DEVELOPMENTAL biology - Abstract
Summary Road construction is now common through wilderness and protected areas in tropical and subtropical countries with adverse consequences for their high native biodiversity. Here, we summarize the scope of the problem and advance specific compromise solutions that reconcile development with conservation. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
29. Horizon scan of global conservation issues for 2011
- Author
-
Sutherland, William J., Bardsley, Sarah, Bennun, Leon, Clout, Mick, Côté, Isabelle M., Depledge, Michael H., Dicks, Lynn V., Dobson, Andrew P., Fellman, Liz, Fleishman, Erica, Gibbons, David W., Impey, Andrew J., Lawton, John H., Lickorish, Fiona, Lindenmayer, David B., Lovejoy, Thomas E., Nally, Ralph Mac, Madgwick, Jane, Peck, Lloyd S., and Pretty, Jules
- Subjects
- *
ENVIRONMENTAL protection , *BIODIVERSITY , *NONGOVERNMENTAL organizations , *INTRODUCED species , *WILDLIFE diseases , *GREENHOUSE gases , *GENETIC techniques , *MOSQUITOES , *MILK consumption , *PESSIMISM - Abstract
This review describes outcomes of a 2010 horizon-scanning exercise building upon the first exercise conducted in 2009. The aim of both horizon scans was to identify emerging issues that could have substantial impacts on the conservation of biological diversity, and to do so sufficiently early to encourage policy-relevant, practical research on those issues. Our group included professional horizon scanners and researchers affiliated with universities and non- and inter-governmental organizations, including specialists on topics such as invasive species, wildlife diseases and coral reefs. We identified 15 nascent issues, including new greenhouse gases, genetic techniques to eradicate mosquitoes, milk consumption in Asia and societal pessimism. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
30. Trophy hunting: Bans create opening for change.
- Author
-
Nowak, Katarzyna, Lee, Phyllis C., Marino, Jorgelina, Mkono, Mucha, Mumby, Hannah, Dobson, Andrew, Harvey, Ross, Lindsay, Keith, Lusseau, David, and Sillero-Zubiri, Claudio
- Subjects
- *
BIODIVERSITY , *HUNTING trophies , *ANIMAL populations - Published
- 2019
- Full Text
- View/download PDF
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