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Hove et al 2002 Juvenile Mussels.pdf
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TRB Library
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HOL-HUE
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Hove et al 2002.pdf
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TRB Library
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HOL-HUE
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Hovingh Linker 1993.pdf
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HOL-HUE
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How a hurricane fueled wildfires in the Florida Panhandle
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The wildfires that broke out in the Florida Panhandle in early March 2022 were the nightmare fire managers had feared since the day Hurricane Michael flattened millions of trees there in 2018. It might sound odd – hurricanes helping to fuel wildfires. But Michael’s 160 mph winds left tangles of dead trees that were ready to burn.
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News & Events
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How and Why Do Insects Migrate?
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Countless numbers of insects migrate within and between continents every year, and yet we know very little about the ultimate reasons and proximate mechanisms that would explain these mass movements. Here we suggest that perhaps the most important reason for insects to migrate is to hedge their reproductive bets. By spreading their breeding efforts in space and time, insects distribute their offspring over a range of environmental conditions. We show how the study of individual long-distance movements of insects may contribute to a better understanding of migration. In the future, advances in tracking methods may enable the global surveillance of large insects such as desert locusts.
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Climate Science Documents
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How complex do models need to be to predict dispersal of threatened species through matrix habitats?
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Persistence of species in fragmented landscapes depends on dispersal among suitable breeding sites, and dispersal is often influenced by the ‘‘matrix’’ habitats that lie between breeding sites. However, measuring effects of different matrix habitats on movement and incorporating those differences into spatially explicit models to predict dispersal is costly in terms of time and financial resources. Hence a key question for conservation managers is: Do more costly, complex movement models yield more accurate dispersal predictions? We compared the abilities of a range of movement models, from simple to complex, to predict the dispersal of an endangered butterfly, the Saint Francis’ satyr (Neonympha mitchellii francisci). The value of more complex models differed depending on how value was assessed. Although the most complex model, based on detailed movement behaviors, best predicted observed dispersal rates, it was only slightly better than the simplest model, which was based solely on distance between sites. Consequently, a parsimony approach using information criteria favors the simplest model we examined. However, when we applied the models to a larger landscape that included proposed habitat restoration sites, in which the composition of the matrix was different than the matrix surrounding extant breeding sites, the simplest model failed to identify a potentially important dispersal barrier, open habitat that butterflies rarely enter, which may completely isolate some of the proposed restoration sites from other breeding sites. Finally, we found that, although the gain in predicting dispersal with increasing model complexity was small, so was the increase in financial cost. Furthermore, a greater fit continued to accrue with greater financial cost, and more complex models made substantially different predictions than simple models when applied to a novel landscape in which butterflies are to be reintroduced to bolster their populations. This suggests that more complex models might be justifiable on financial grounds. Our results caution against a pure parsimony approach to deciding how complex movement models need to be to accurately predict dispersal through the matrix, especially if the models are to be applied to novel or modified landscapes.
Key words: capture–mark–recapture; connectivity; dispersal; habitat fragmentation; matrix habitat; Neonympha mitchellii francisci; restoration; spatially explicit individual-based simulation model.
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Climate Science Documents
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How Does Climate Change Affect Biodiversity?
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The most recent and complex bioclimate
models excel at describing species’ current
distributions. Yet, it is unclear which models
will best predict how climate change will affect
their future distributions.
8 SEPTEMBER 2006 VOL 313 SCIENCE
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How does climate change cause extinction?
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Anthropogenic climate change is predicted to be a major cause of species extinctions in the next 100 years. But what will actually cause these extinctions? For example, will it be limited physiological tolerance to high temperatures, changing biotic interactions or other factors? Here, we systematically review the proximate causes of climate-change related extinctions and their empirical support. We find 136 case studies of climatic impacts that are potentially relevant to this topic. However, only seven ident- ified proximate causes of demonstrated local extinctions due to anthropogenic climate change. Among these seven studies, the proximate causes vary widely. Surprisingly, none show a straightforward relation- ship between local extinction and limited tolerances to high temperature. Instead, many studies implicate species interactions as an important proximate cause, especially decreases in food availability. We find very similar patterns in studies showing decreases in abundance associated with climate change, and in those studies showing impacts of climatic oscillations. Collectively, these results highlight our disturbingly limited knowledge of this crucial issue but also support the idea that changing species interactions are an important cause of documented population declines and extinctions related to climate change. Finally, we briefly outline general research strategies for identifying these proximate causes in future studies.
Keywords: climate change; extinction; physiological tolerances; species interactions
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Climate Science Documents
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How does climate change influence demographic processes of widespread species? Lessons from the comparative analysis of contrasted populations of roe deer
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How populations respond to climate change depends on the interplay between life history, resource avail- ability, and the intensity of the change. Roe deer are income breeders, with high levels of allocation to reproduction, and are hence strongly constrained by the availability of high quality resources during spring. We investigated how recent climate change has influenced demographic processes in two populations of this widespread species. Spring began increasingly earlier over the study, allowing us to identify 2 periods with contrasting onset of spring. Both populations grew more slowly when spring was early. As expected for a long-lived and iteroparous species, adult survival had the greatest potential impact on population growth. Using perturbation analyses, we measured the relative contribution of the demographic parameters to observed variation in population growth, both within and between periods and populations. Within peri- ods, the identity of the critical parameter depended on the variance in growth rate, but variation in recruit- ment was the main driver of observed demographic change between periods of contrasting spring earliness. Our results indicate that roe deer in forest habitats cannot currently cope with increasingly early springs. We hypothesise that they should shift their distribution to richer, more heterogeneous landscapes to offset energetic requirements during the critical rearing stage.
Keywords
Age-structured populations, demographic change, income breeding, perturbation analysis, population growth, Recruitment, Stochastic environment, Survival.
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Climate Science Documents
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How Does It Feel to Be Like a Rolling Stone? Ten Questions About Dispersal Evolution
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This review proposes ten tentative answers to frequently asked ques- tions about dispersal evolution. I examine methodological issues, model assumptions and predictions, and their relation to empirical data. Study of dispersal evolution points to the many ecological and genetic feedbacks affecting the evolution of this complex trait, which has contributed to our better understanding of life-history evolution in spatially structured populations. Several lines of research are suggested to ameliorate the exchanges between theoretical and empirical studies of dispersal evolution.
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