A Great Escape: Resource availability and density-dependence shape population dynamics along trailing range edges

Ecography
By: , and 

Links

Abstract

Populations along geographical range limits are often exposed to unsuitable climate and low resource availability relative to core populations. As such, there has been a renewed focus on understanding the factors that determine range limits to better predict how species will respond to global change. Using recent theory on range limits and classical understanding of density dependence, we evaluated the influence of resource availability on the snowshoe hare Lepus americanus along its trailing range edge. We estimated variation in population density, habitat use, survival, and parasite loads to test the Great Escape Hypothesis (GEH), i.e. that density dependence determines, in part, a species' persistence along trailing edges. We found that variability in resource availability affected density and population fluctuations and led to trade-offs in survival for snowshoe hare populations in the northeastern USA. Hares living in resource-limited environments had lower and less variable population density, yet higher survival and lower parasitism compared to populations living in resource-rich environments. We suggest that density-dependent dynamics, elicited by resource availability, provide hares a unique survival advantage and partly explain persistence along their trailing edge. We hypothesize that this low-density escape from predation and parasitism occurs for other prey species along trailing edges, but the extent to which it occurs is likely conditional on the quality of matrix habitat. Our work indicates that biotic factors play an important role in shaping species' trailing edges and more detailed examination of non-climatic factors is warranted to better inform conservation and management decisions.

Study Area

Publication type Article
Publication Subtype Journal Article
Title A Great Escape: Resource availability and density-dependence shape population dynamics along trailing range edges
Series title Ecography
DOI 10.1111/ecog.06633
Volume 2023
Issue 8
Year Published 2023
Language English
Publisher Wiley
Contributing office(s) Northeast Climate Adaptation Science Center
Description e06633, 12 p.
Country United States
State New Hampshire, Vermont
Other Geospatial Connecticut Lakes, Nulhegan Basin, White Mountain National Forest
Google Analytic Metrics Metrics page
Additional publication details