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Influence of Spatial Scale on Estimates of Substrate Use by Benthic Darters
Author(s) -
Welsh Stuart A.,
Perry Sue A.
Publication year - 1998
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8675(1998)018<0954:iossoe>2.0.co;2
Subject(s) - etheostoma , substrate (aquarium) , quadrat , benthic zone , spatial ecology , habitat , spatial heterogeneity , ecology , spatial variability , cobble , environmental science , biology , fishery , transect , mathematics , fish <actinopterygii> , statistics
Benthic habitats in streams are heterogeneous, in part because of differences in rock size. Because of this variation in rock size, our perception of substrate use by benthic fishes may be influenced by the spatial scale of observation. We used a quadrat that was subdivided into twenty‐five 5 × 5‐cm cells to examine substrate use by four species of darters at three spatial scales (25 × 25 cm, 15 × 15 cm, and 5 × 5 cm). Estimates of substrate use in these darters differed across small changes in spatial scale because of substrate heterogeneity and the position of the darter relative to the substrate. Estimates of substrate size increased with spatial scale for rainbow darters Etheostoma caeruleum and banded darters E. zonale , species that occurred between rocks, but decreased with spatial scale for the greenside darter E. blennioides , a species that occurred on top of rocks. The eastern sand darter Ammocrypta pellucida occurred over sand substrate (a homogeneous habitat) and did not differ in substrate use across spatial scales. In microhabitat studies, substrate use should be examined across several spatial scales (particularly for fishes that occur in heterogeneous habitats) because estimates of substrate use are affected by small changes in spatial scale.