Predation and competition play an important role in the structure of communities in many different ecosystems. The importance of these biotic interactions in the structure of stream communities remains a pressing question in community ecology. this question will be examined in two large arrays of replicated experimental streams; one of 16 streams and one of 24 streams, and in a program of field sampling and field experiments at Mountain Lake Biological Station. The experimental streams are constructed to mimic the pool an driffle habitats respectively of Appalacian mountain streams. Several benthic species common in these streams will be used. Etheostoma flabellare, Eurycea bislineata, Cottus bairdi, and Gyrinophilus porphyriticus, along with the midwater predator Salvelinus fontinalis, to assemble complex communities. This will be the first large-scale in lotic ecosystems. This program of research will enable stream ecologists to better interpret patterns of distribution and abundance of species in small streams and to better understand the large body of data on habitat segregation and microhabitat use patterns in stream communities.
