Coexistence in streams: Do source-sink dynamics allow salamanders to persist with fish predators?

Oecologia
By:  and 

Links

Abstract

Theory suggests that source–sink dynamics can allow coexistence of intraguild predators and prey, but empirical evidence for this coexistence mechanism is limited. We used capture–mark–recapture, genetic methods, and stable isotopes to test whether source–sink dynamics promote coexistence between stream fishes, the intraguild predator, and stream salamanders (Dicamptodon aterrimus), the intraguild prey. Salamander populations from upstream reaches without fish were predicted to maintain or supplement sink populations in downstream reaches with fish. We found instead that downstream reaches with fish were not sinks even though fish consumed salamander larvae—apparent survival, recruitment, and population growth rate did not differ between upstream and downstream reaches. There was also no difference between upstream and downstream reaches in net emigration. We did find that D. aterrimus moved frequently along streams, but believe that this is a response to seasonal habitat changes rather than intraguild predation. Our study provides empirical evidence that local-scale mechanisms are more important than dispersal dynamics to coexistence of streams salamanders and fish. More broadly, it shows the value of empirical data on dispersal and gene flow for distinguishing between local and spatial mechanisms of coexistence.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Coexistence in streams: Do source-sink dynamics allow salamanders to persist with fish predators?
Series title Oecologia
DOI 10.1007/s00442-011-1935-y
Volume 166
Issue 4
Year Published 2011
Language English
Publisher Springer Link
Contributing office(s) Northern Rocky Mountain Science Center
Description 12 p.
First page 1043
Last page 1054
Country United States
State Idaho
Other Geospatial Lochsa River basin of the Clearwater River
Google Analytic Metrics Metrics page
Additional publication details