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

Authors: A M Kissel; S Tenan; Erin Muths
Contribution Number: 774

https://www.mdpi.com/1424-2818/12/12/478

Abstract/Summary

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.

Publication details
Published Date: 2020-12-12
Outlet/Publisher: Diversity 2020, 12, 478; doi:10.3390/d12120478
Media Format: .PDF

ARMI Organizational Units:
Rocky Mountains, Southern - Biology
Topics:
Monitoring and Population Ecology; Species and their Ecology
Place Names:
Colorado
Keywords:
amphibians; climate; conservation; demographics; density effects; detection probability
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