Environmental and demographic mechanisms underlying population dynamics provide relative stability in an island songbird

Ecology
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Abstract

Understanding demographic and ecological mechanisms underlying population dynamics is a key goal in population ecology and can inform effective conservation and management. Species may be well adapted to persist under normal ranges of environmental conditions, but increasingly novel conditions due to climate change may strain their demographic buffering mechanisms. Small isolated populations on islands are expected to be especially vulnerable to declines caused by novel environmental conditions, but the ecological drivers of population dynamics on islands are often unknown. We used an integrated population model to (1) examine ecological drivers of population growth and (2) assess global population trends of the Island Scrub-Jay (Aphelocoma insularis) from 2009 to 2019. Our results suggest that population size increased slightly over this interval despite declines during severe drought. We also found evidence that density dependence, precipitation, and food availability affected fecundity and the survival of nonbreeding individuals. Breeder survival was relatively stable and had a weak effect on population growth as expected for long-lived species. Overall, our results provide an optimistic snapshot for this species by demonstrating resilience to contemporary drought but also emphasize the species' potential vulnerability due to its small population size.

Suggested Citation

Mouton, J.C., Pesendorfer, M.B., Hostetter, N.J., Morrison, S.A., and Sillett, T.S., 2026, Environmental and demographic mechanisms underlying population dynamics provide relative stability in an island songbird: Ecology, v. 107, no. 5, e70409, 16 p., https://doi.org/10.1002/ecy.70409.

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Publication type Article
Publication Subtype Journal Article
Title Environmental and demographic mechanisms underlying population dynamics provide relative stability in an island songbird
Series title Ecology
DOI 10.1002/ecy.70409
Volume 107
Issue 5
Publication Date May 24, 2026
Year Published 2026
Language English
Publisher Ecological Society of America
Contributing office(s) Coop Res Unit Atlanta
Description e70409, 16 p.
Country United States
State California
Other Geospatial Santa Cruz Island
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