Relationships between Fish Communities and Habitat before and after a Typhoon Season in Tropical Mountain Streams

Abstract

The responses of habitat and fish communities to extreme hydrological and habitat disturbance in typhoon-prone mountain streams are not studied much. Such landscape–climate settings may provide a unique opportunity for fish to evolve without special habitat adaptation and involve different assembly rules compared to temperate regions. This study aimed to compare fish communities and habitat factors before and after the typhoon season and to test the influences of various aspects of habitat on fish assemblages between seasons. Fish and habitats were surveyed at 30 wadable stream sites in March and December 2010 in tropical southern Taiwan. Habitat variables differed between the pre-typhoon and post-typhoon seasons. Higher species richness and the total number of fish caught in the pre-typhoon season indicated fast recovery. Benthic fish were more vulnerable to typhoon disturbances than sub-benthic fish. Contrary to the original hypothesis, fish communities were more strongly related to physical habitats than water quality and riparian conditions. In addition, consistently high fish variance explained by habitat measures in the dry seasons indicated that environmental filtering predominated. Dominant fish species were related to main habitat gradients, characterized by low species richness but high beta-diversity. Our findings provide implications for fish conservation in typhoon-prone mountain streams.