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Communication at the NABS Annual meeting, Keystone, 2000
(18) FISH MEDIATED ALTERATION OF INVERTEBRATE COMMUNITY SIZE DISTRIBUTIONS:
CONSEQUENCES FOR SECONDARY PRODUCTION.
M.G. Butler1, K.D. Zimmer1, M.A. Hanson2, and W.G. Duffy3. 1Department of Zoology, North Dakota State University, Fargo, ND 58105, 2Wetland Wildlife and Populations Research Group, Minnesota Department of Natural Resources, Bemidji, MN 56601, 3California Cooperative Fisheries Research Unit, Humboldt State University, Arcata, CA 95521
Many studies have assessed the impacts of fish predation on invertebrate
community structure, but relationships between community structure and
community-level processes such as production are poorly known. We
estimated the size distributions of aquatic invertebrates in two prairie
wetlands, one supporting a population of fathead minnows and the other
fishless. Size distributions were then coupled with allometric models to estimate community-level production and specific production rates in three depth strata and on each of three dates. Minnows reduced invertebrate abundance across a wide spectrum of size classes, such that the shape of the resulting size distributions differed little from that
in the fishless site. With similar size spectra and size-dependent
production:biomass ratios, specific production rates differed little
between wetlands with and without minnows. Higher standing-stock biomass in
the fishless wetland resulted in higher production rates per unit area.
Thus, differences in community production between the two wetlands were
influenced more by the effects of fathead minnows on standing-stock biomass
than by alteration of invertebrate size distributions.
Presented at 1:15 PM on Monday, May 29, 2000 in Wetlands and Lentic Ecology I
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