Multiple environmental gradients influence the distribution and abundance of a key forest-health indicator species in the Southern Appalachian Mountains, USA
The effects of global climate change are threatening biodiversity, with particular concern for amphibians, whose survival often depends on specific abiotic conditions. To predict how future climate change will affect amphibian populations, it is first necessary to understand how patterns of abundance are shaped by multiple environmental conditions at both local and regional scales.
Plethodontid salamander are a group of lungless ectotherms that require cool and moist habitats to survive. While the broad elevational distribution and abundance patterns are well-understood, other important abiotic gradients exist within montane systems that are contributing to fine-scale spatial abundance patterns. We aim to assess the fine-scale spatial abundance of a plethodontid salamander across two key environmental gradients: temperature and moisture.
We conducted area-constrained repeated point-count surveys at plots situated across temperature and moisture gradients in western North Carolina. Each plot was surveyed on 4 occasions, and site and survey-level covariates were measured.
We found heterogeneous abundance patterns across these two gradients whereby warmer low elevations contain the greatest abundance near stream sides, where conditions are cooler and wetter than the regional landscape. At cooler, higher elevations, salamanders are distributed more uniformly across the broader landscape, likely as a result of the suitable regional climate.
Fine-scale habitat associations of plethodontids are driven by temperature and moisture, and the spatial patterns of suitable microhabitats drive regional scale patterns. Incorporating multiple environmental gradients provides a more biologically relevant prediction of abundance patterns, which will help inform conservation and management strategies especially in the context of climate change.
KeywordsSalamander Plethodon Bayesian binomial mixture modelling Climate change Environmental gradients Montane Abundance
We would like to thank Katie Greene for extensive field help, as well as the staff at Highlands Biological Station. This work was supported through The Bruce Family Scholarship in Herpetology Grant-in-Aid from Highlands Biological Station and the Herpetologists’ League EE Williams Research Grant. We thank two anonymous reviewers for their helpful feedback on earlier versions of this manuscript. This study was conducted following The Ohio State University IACUC #2016A00000026, with permission through the US Forest Service permit (NAN45716).
Compliance with ethical standards
Conflict of interest
The authors have no conflicts of interest to declare.
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