Aquatic pollution increases use of terrestrial prey subsidies by stream fish

Journal of Applied Ecology
By: , and 



  1. Stream food webs are connected with their riparian zones through cross-ecosystem movements of energy and nutrients. The use and impact of terrestrial subsidies on aquatic consumers is determined in part by in situ biomass of aquatic prey. Thus, stressors such as aquatic pollutants that greatly reduce aquatic secondary production could increase the need for and reliance of stream consumers on terrestrial resource subsidies.
  2. To test this hypothesis, we surveyed stream fish, their diets and resource availability in 16 subalpine streams over a regional gradient of trace metals known to strongly impact aquatic insect communities (i.e. fish prey) in the Colorado Rocky Mountains, USA.
  3. Fish increased their reliance on terrestrial insect prey as stream metals increased. Relative biomass of terrestrial insects in stomach contents of Brook and Brown Trout increased with respect to aquatic insect biomass and total stomach contents. Drifting insect biomass showed a declining trend for aquatic, but not terrestrial insects, over the metal gradient. Trout densities were unrelated to metal concentrations in streams where we found fish.
  4. Synthesis and applications. Our results indicate that diets of aquatic consumers can become more terrestrial as aquatic stressors that limit in situ food production increase and that these subsidies may compensate for loss of aquatic resources. This work implies an important connection between preserving aquatic–terrestrial linkages and management of fish populations in stressed watersheds. Specifically, intact riparian zones and aquatic–terrestrial linkages are likely to be important for maintaining trout production in streams with moderate metal contamination.

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Publication type Article
Publication Subtype Journal Article
Title Aquatic pollution increases use of terrestrial prey subsidies by stream fish
Series title Journal of Applied Ecology
DOI 10.1111/1365-2664.12543
Volume 53
Issue 1
Year Published 2016
Language English
Publisher Wiley
Contributing office(s) Fort Collins Science Center, Contaminant Biology Program
Description 10 p.
First page 44
Last page 53
Country United States
State Colorado
Online Only (Y/N) N
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
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