HR: 16:00h
AN: NB24C-03    [Abstracts]
TI: Importance of Resource Subsidies to Animals in Freshwater Ecosystems
AU: * Koch, B J
EM: bkoch@uwyo.edu
AF: Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071 United States
AU: Hall, R O
EM: bhall@uwyo.edu
AF: Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071 United States
AB: Many streams receive large resource subsidies from adjacent ecosystems. These subsidies take a variety of forms including terrestrial organic matter, dissolved nutrients, or animals. Some subsidies can have important consequences for in-stream consumers in the recipient system, while in other systems they are unimportant. We present a framework for establishing the conditions under which food subsidies to streams are likely to be important to animal consumers. Importance of cross-system subsidies will vary as a function of the spatial/temporal scales of interest. Attributes of the subsidy (e.g., stoichiometric quality) or of the donor/recipient systems (e.g., productivity gradients) can be used to predict conditions under which subsidies are important to in-stream consumers. We propose a hypothesis that classifies the importance of subsidies to streams as high, intermediate, or low based on the subsidy's nutritive quality and its flux relative to autochthonous primary production. Thus, importance will be high when the flux of a highly nutritious subsidy is a large proportion of in-stream productivity. Importance will be low in the opposite case. We test this hypothesis using data from the literature. This framework is intended to facilitate cross-system comparisons that test the ecological conditions governing the importance of resource subsidies to freshwater ecosystems.
DE: 9810 New fields (not classifiable under other headings)
DE: 9901 NABS Student Award - Basic Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly