Persistence of Fish Species Associations in Pools of a Small Stream of the Southern Great Plains

Abstract

Persistence of direct contacts among species has important implications for the potential of taxa to influence each other's traits or evolutionary trajectories. We examined persistence of species (or “ecospecies”) associations in Brier Creek, Oklahoma, based on visual surveys on seven dates 1982–1983 and on 12 dates 1995–2003 in 14 contiguous pools. Fishes were considered to be associated, in direct contact, if they occurred within the same pool during a survey. Mantel tests showed that associations among 11 common taxa from survey to survey were highly variable, but were significantly concordant across 11 of 18 intervals between surveys. Most floods and droughts were not followed by decreased concordance of associations, but associations did change after the second of two very severe droughts (1998 and 2000). Within-year associations were highly concordant in 1983 and in 1996, years with the most repeated surveys. Patterns of association were highly concordant across years for surveys in late summer and episodically concordant for surveys in May 1995–2003, but not in autumn. A cluster analysis comparing all surveys showed that associations among taxa differed between earlier (1982–83) and later (1995–2003) surveys. For some subsets of taxa, we found strong, consistent association across most surveys.