Spatial and temporal variation in fish assemblages of drying stream pools: The role of abiotic and biotic factors

摘要: Droughts and summer drying create unusual temporary aquatic habitats in the form of isolated pools many small streams around world. To examine spatial temporal variation fish community structure stream pools, their relation to abiotic environmental variables, associations among species, were sampled during 1995 1996 from four Ozark mountains, Arkansas, USA. Redundancy analysis physical-chemical variables showed significant differences sites, but no difference between years or site by year interaction. Stream sites separated consistently along axes one (habitat heterogeneity) two (temperature/canopy cover) both years. species-size class densities a Groupings based on assemblages not well explained measured at pool scale, related location within drainage basin, these groupings differed There 27 (15.8%) 10 (5.8%) found classes 1996, respectively, all positive. Pool depth, habitat heterogeneity, size dissolved oxygen/canopy cover important local factors depending response examined. In years, large total density, central stoneroller density (≥80 mm TL), sunfish (<80 mm TL) positively depth. Otherwise, there was consistent relationship dependent (fish species richness) for given variable. These results support hypothesis that are structuring harsh environments, importance those varies temporally, regional influences appear override conditions as pools. Predation terrestrial vertebrates may also be an factor has been largely overlooked.