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Presented at the NABS Annual meeting, Athens, Georgia, 2003
in Tropical Stream Ecology II
Migratory fishes as material and functional linkages across Neotropical landscapes
A.S. Flecker1, B.W. Taylor2, R.O. Hall, Jr.2, and J.T. Anderson1. 1Department of Ecology & Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA, 2Department of Zoology & Physiology, University of Wyoming, Laramie, WY 82071, USA
Migratory fishes are major components of many South American river systems. Massive fish migrations are renowned and migratory species constitute the mainstay of South American freshwater fisheries. Here we discuss the importance of migratory fishes as material and functional linkages across Neotropical landscapes. We suggest that large fish migrations can represent significant subsidies of nutrients from floodplains to Andean piedmont food webs. However, migratory species may be important not only as material inputs, but as organisms that can play unique functional roles in ecosystems. For example, our work with the flannelmouth characin, Prochilodus mariae, a migratory detritivore that is often seasonally abundant in Andean piedmont streams, reveals that this species strongly modulates community structure and ecosystem function. Selective exclusion of Prochilodus changes the composition of invertebrate and algal assemblages, as well as the dynamics of sediments and nutrients. In addition, some migratory fishes in Neotropical rivers are frugivorous and they potentially play unique functional roles as fruit dispersal agents for a variety of tree species found in seasonally flooded forests. We conclude that the conservation of migratory fishes is a critical priority for maintaining the ecological integrity of many Neotropical river systems.
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