Density dependence and adult survival drive the dynamics in two high elevation amphibian populations

Diversity
By: , and 

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Abstract

Amphibian conservation has progressed from the identification of declines to mitigation, but efforts are hampered by the lack of nuanced information about the effects of environmental characteristics and stressors on mechanistic processes of population regulation. Challenges include a paucity of long-term data and scant information about the relative roles of extrinsic (e.g., weather) and intrinsic (e.g., density dependence) factors. We used a Bayesian formulation of an open population capture-recapture model and >30 years of data to examine intrinsic and extrinsic factors regulating two adult boreal chorus frogs (Pseudacris maculata) populations. We modelled population growth rate and apparent survival directly, assessed their temporal variability, and derived estimates of recruitment. Populations were relatively stable (geometric mean population growth rate >1) and regulated by negative density dependence (i.e., higher population sizes reduced population growth rate). In the smaller population, density dependence also acted on adult survival. In the larger population, higher population growth was associated with warmer autumns. Survival estimates ranged from 0.30–0.87, per-capita recruitment was <1 in most years, and mean seniority probability was >0.50, suggesting adult survival is more important to population growth than recruitment. Our analysis indicates density dependence is a primary driver of population dynamics for P. maculata adults.

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Publication type Article
Publication Subtype Journal Article
Title Density dependence and adult survival drive the dynamics in two high elevation amphibian populations
Series title Diversity
DOI 10.3390/d12120478
Volume 12
Issue 12
Year Published 2020
Language English
Publisher MDPI
Contributing office(s) Fort Collins Science Center
Description 478, 15 p.
Country United States
State Colorado
Other Geospatial Lily Pond, Matthews Pond
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