Search citation statements
Paper Sections
Citation Types
Year Published
Publication Types
Relationship
Authors
Journals
Despite increased risk of extinction through stochastic events, peripheral populations are conservation priorities as the distribution of endangered species tends to contract to the periphery of historic ranges rather than toward the core. Trailing-edge populations and mountain isolates, which may become more common as climate change drives range shifts, are an important realm of inquiry and contain important reserves of genetic variation. We use long-term monitoring data from the southernmost population of a widespread species to test the hypothesis that peripheral populations display distinct demographic profiles from core populations. The red squirrel (Tamiasciurus hudsonicus) is predicted to recede from its southern border in response to climate-induced habitat change. We estimate key demographic parameters for this endangered population using survival and reproduction schedules and compare the dynamics to core populations of this and related species. This peripheral population exhibits higher adult mortality, and suffers associated impacts on reproductive output, which results in a demography distinct from core populations and phylogenetically similar species. Poor adult survival, similar to a population that experiences extremely high hunting pressure, has resulted in this normally iteroparous species becoming functionally semelparous at the periphery. Understanding differences in demographic function between peripheral and core populations is key if management strategies are to be effective in supporting continued persistence of at risk populations in the face of range shifts of species or habitats driven by environmental change. Keywords: Life table, peripheral population, sky island, Tamiasciurus fremonti, Tamiasciurus hudsonicus, trailing edge 1.0 Introduction Informed management of populations facing certain future ecosystem change requires accurate assessments of population size and key demographic parameters, which often can be obtained only through long-term research and monitoring programs (Magurran et al. 2010). Frequently, different stage or age classes of populations experience diverse mortality pressures or exhibit variation in reproductive value (Reid et al. 2004). Early indications of ecological imbalance, future population collapse, or expansion can be recognized by close monitoring of demographics and age distributions. Fine-scale knowledge of variation in species' survival and fecundity between life stages or ages should improve the cost-effectiveness of management programs by allowing conservation effort to be applied where and when the greatest impact can be realized. For example, where mature individuals display the highest reproductive values, efforts could target these individuals for protection (Arrigoni et al. 2011) or removal in the case of invasive species (Harris et al. 2009). As climate change leads to altered species distributions (Parmesan 2006) and less stable environmental conditions, the demographic function of populations can be severely impacted. Populations at the periph...
Despite increased risk of extinction through stochastic events, peripheral populations are conservation priorities as the distribution of endangered species tends to contract to the periphery of historic ranges rather than toward the core. Trailing-edge populations and mountain isolates, which may become more common as climate change drives range shifts, are an important realm of inquiry and contain important reserves of genetic variation. We use long-term monitoring data from the southernmost population of a widespread species to test the hypothesis that peripheral populations display distinct demographic profiles from core populations. The red squirrel (Tamiasciurus hudsonicus) is predicted to recede from its southern border in response to climate-induced habitat change. We estimate key demographic parameters for this endangered population using survival and reproduction schedules and compare the dynamics to core populations of this and related species. This peripheral population exhibits higher adult mortality, and suffers associated impacts on reproductive output, which results in a demography distinct from core populations and phylogenetically similar species. Poor adult survival, similar to a population that experiences extremely high hunting pressure, has resulted in this normally iteroparous species becoming functionally semelparous at the periphery. Understanding differences in demographic function between peripheral and core populations is key if management strategies are to be effective in supporting continued persistence of at risk populations in the face of range shifts of species or habitats driven by environmental change. Keywords: Life table, peripheral population, sky island, Tamiasciurus fremonti, Tamiasciurus hudsonicus, trailing edge 1.0 Introduction Informed management of populations facing certain future ecosystem change requires accurate assessments of population size and key demographic parameters, which often can be obtained only through long-term research and monitoring programs (Magurran et al. 2010). Frequently, different stage or age classes of populations experience diverse mortality pressures or exhibit variation in reproductive value (Reid et al. 2004). Early indications of ecological imbalance, future population collapse, or expansion can be recognized by close monitoring of demographics and age distributions. Fine-scale knowledge of variation in species' survival and fecundity between life stages or ages should improve the cost-effectiveness of management programs by allowing conservation effort to be applied where and when the greatest impact can be realized. For example, where mature individuals display the highest reproductive values, efforts could target these individuals for protection (Arrigoni et al. 2011) or removal in the case of invasive species (Harris et al. 2009). As climate change leads to altered species distributions (Parmesan 2006) and less stable environmental conditions, the demographic function of populations can be severely impacted. Populations at the periph...
A mechanistic understanding of phenology, the seasonal timing of life history events, is important for understanding species’ interactions and the potential responses of ecological communities to a rapidly changing climate. We present analysis of a seven-year dataset on the breeding phenology of wood frogs (Rana sylvatica), tiger salamanders (Ambystoma tigrinum), blue-spotted salamanders (Ambystoma laterale), and associated unisexual Ambystoma salamanders from six wetlands in Southeast Michigan, USA. We assess whether the ordinal date of breeding migrations varies among species, sexes, and individual wetlands, and we describe the specific environmental conditions associated with breeding migrations for each species/sex. Breeding date was significantly affected by species/sex identity, year, wetland, and the interactions between species/sex and year as well as wetland and year. There was a great deal of variation among years, with breeding occurring nearly synchronously among groups in some years but widely spaced between groups in other years. Specific environmental triggers for movement varied for each species and sex and changed as the breeding season progressed. In general, salamanders responded to longer temperature lags (more warmer days in a row) than wood frogs, whereas wood frogs required longer precipitation lags (more rainy days in a row) than salamanders. Wood frogs were more likely to migrate around the time of a new moon, whereas in contrast, Ambystoma salamander migration was not associated with a moon phase. Ordinal day was an important factor in all models, suggesting that these amphibians require a latency period or similar mechanism to avoid breeding too early in the year, even when weather conditions appear favorable. Male wood frogs migrated earlier than female wood frogs, and male blue-spotted salamanders migrated earlier than female A. laterale and associated unisexual females. Larger unisexual salamanders migrated earlier than smaller individuals. Differences in species’ responses to environmental cues led to wood frogs and A. laterale breeding later than tiger salamanders in colder years but not in warmer years. This suggests that, as the climate warms, wood frog and A. laterale larvae may experience less predation from tiger salamander larvae due to reduced size differences when they breed simultaneously. Our study is one of few to describe the proximate drivers of amphibian breeding migrations across multiple species, wetlands, and years, and it can inform models predicting how climate change may shift ecological interactions among pond-breeding amphibian species.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.