Publication Date:
2022-05-25
Description:
Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecological Applications 16 (2006): 666–677.
Description:
We used population models to explore the effects of the organochlorine contaminant
p,p'DDE and fluctuations in vole availability on the population dynamics of Burrowing
Owls (Athene cunicularia). Previous work indicated an interaction between low biomass of voles in the diet and moderate levels of p,p'DDE in Burrowing Owl eggs that led to reproductive impairment. We constructed periodic and stochastic matrix models that incorporated three vole population states observed in the field: average, peak and crash years. We modeled varying frequencies of vole crash years and a range of impairment of owl demographic rates in vole crash years. Vole availability had a greater impact on owl population growth rate than reproductive impairment if vole populations peaked and crashed frequently. However, this difference disappeared as the frequency of vole crash years declined to once per decade. Fecundity,
the demographic rate most affected by p,p'DDE, had less impact on population growth rate
than adult or juvenile survival. A life table response experiment of time-invariant matrices for
average, peak and crash vole conditions showed that low population growth under vole crash
conditions was due to low adult and juvenile survival rates, whereas the extremely high population growth under vole peak conditions was due to increased fecundity. Our results suggest
that even simple models can provide useful insights into complex ecological interactions. This is
particularly valuable when temporal or spatial scales preclude manipulative experimental work
in the field or laboratory.
Description:
Field work was supported by grants from the U.S. Navy EFA West, California Department of Fish and Game,
and the National Fish and Wildlife Foundation to D. K. Rosenberg. Analysis was supported
in part by the U.S. Environmental Protection Agency (R-82908901-0).
Keywords:
Athene cunicularia
;
Burrowing Owl
;
DDE
;
Elasticity
;
Interactive effects
;
Matrix population model
;
Multiple stressors
;
Population level risk assessment
;
Prospective analysis
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
273377 bytes
Format:
application/pdf
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