HR: 15:45h
AN: NB24C-02    [Abstracts]
TI: Seasonal differences in riparian consumer diet and insect communities in an Oregon Coast Range watershed food web.
AU: * Robillard, A
EM: robillaa@onid.orst.edu
AF: Department of Fisheries & Wildlife - Oregon State University, 104 Nash Hall Oregon State Univeristy , Corvallis, OR 97331 United States
AU: Li, J
EM: judith.li@oregonstate.edu
AF: Department of Fisheries & Wildlife - Oregon State University, 104 Nash Hall Oregon State Univeristy , Corvallis, OR 97331 United States
AB: In riparian areas, terrestrial and aquatic habitats overlap creating zones where they interact as an aquatic-terrestrial interface. This coupling allows energy to move between systems and generates intertwining food webs. Thus, vertebrate riparian consumers, such as fish or birds, potentially have alternative prey from sources external to their habitats. The purpose of our study was to explore this reciprocal exchange in an alder dominated riparian forest of the Oregon Coast Range. Diet samples were collected from birds and fish in summer and fall 2003 with a suite of insect samples at Honeygrove Creek and two of its small tributaries. In a comparison of emerging aquatic insects and flying terrestrial insects during June and again in September, we detected seasonal differences in terrestrial and aquatic insects available to riparian consumers. Despite this availability of externally derived prey, fish depended more on resources derived from within their respective habitats during summer. Cutthroat trout (Oncorhynchus clarkii) and Coho salmon (Oncorhynchus kitsutch) ate more juvenile aquatic than adult aquatic or terrestrial insects. During fall, the same pattern was exhibited by Coho but Cutthroat trout appeared to consume a slightly greater number of terrestrial insects. The preliminary analysis of bird diet samples from commonly encountered species such as, Swainson's thrush, Song Sparrow, and Pacific-slope Flycatcher, showed more terrestrial derived prey in their diets than aquatic during the summer sampling season.
DE: 9901 NABS Student Award - Basic Research
DE: 9903 NABS Student Award Methodology
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly