Frontiers of Biogeography

Climate change already affects species in many ecosystems worldwide. Since climate is an important component of a species’ ecological niche, up-to-date information about climatic niches is needed to model future species distributions in a context of climate change. The eastern red-backed salamander (Plethodon cinereus) is a wide-ranging woodland species and one of the most abundant vertebrates in northeastern North America. Though salamanders contribute to several forest ecosystem functions, little is known about their climatic niche and future distribution. Using a dataset of 400,090 observations from 8302 localities in 5 Canadian provinces and 22 American states, we determined the current climatic niche of P. cinereus and predicted how the species’ distribution could shift in a context of climate change, especially in the northern part of its range. We also aimed to document factors that could affect the species’ distribution. We show that P. cinereus can live in various geographic and climatic conditions and tolerate a wide range of seasonal temperatures. The species’ current potential and future (until 2061–2080) distributions show a gap of up to 400 km with the northern limit of its current observed distribution. Assuming a mean colonization rate of approximately 100 m per year, we calculated that P. cinereus would need about 4000 years to reach the northern limit of the future distribution range modeled for the 2061–2080 period. The climate-modeled future distribution suggests that the presence of P. cinereus could decrease in the south and increase in the north. This, combined with the potential presence of habitats that are unsuitable for the species’ colonization in the north and with interspecific interactions in the south, could induce a contraction of the species’ range. Regardless of climate warming, the physical environment and natural and anthropic disturbances could also limit the species’ northern post-glaciation migration.

The effects of climate and landscape change on biodiversity are relatively well described. However, there is limited understanding of the interactions between these processes, which generally operate at differing spatial scales. My objective was to evaluate the synergistic effects of climate and landscape changes on persistence and range shift dynamics. The model species was the Cabrera vole, Microtus cabrerae, a habitat specialist with limited dispersal ability. The present study demonstrated that, as a result of the combined effects of climate and landscape change, this species’ future potential distribution will be considerably reduced. The combined effect of climate change and landscape connectivity was assessed using the software MetaLandSim, a newly developed package, with a good balance between data requirements and output quality, allowing researchers to account for connectivity and dispersal in range forecasting. With this R package, the species’ metapopulational dynamics could be simulated at the landscape scale, and range expansion for different connectivity scenarios could be computed.

In a recent study, Wood et al. (2017 Phil. Trans. Roy. Soc. B 372, 20160122) utilized a novel set of spatial and temporal analyses to identify which factors were most strongly correlated with changes in human infectious disease burdens from 1990 to 2010 in 60 countries. Using the statistical analyses and findings of this article as a framework, I have identified three important insights and challenges that this research presents for disease biogeography moving forward. First, the main factor still limiting disease biogeography research progress is underreported or absent data – particularly in the case of neglected tropical diseases. Second, the use of disability-adjusted life years instead of indirect measures of disease burden should be a focal point of disease biogeography research since it allows for comparisons of lethal and non-lethal diseases. Finally, disease biogeography studies that utilize country-level statistical analyses may be better at identifying demographic and economic drivers than environmental or biological drivers.