Spatial and temporal patterns in the fish assemblages of individual pools in a midwestern stream (U.S.A.)

Abstract

The composition and consistency of fish assemblages in 14 adjacent pools (6-120 m long) of a clear-water, limestone and gravel creek in midwestern U.S.A. were quantified in eight snorkeling surveys over 19 months, to establish a baseline of natural variation in the system at this scale. The fauna of the stream was dominated numerically by minnows (Cyprinidae), sunfish and black bass (Centrarchidae), and topminnows (Fundulidae). The pool fish fauna of the total 1 km reach (including all 14 pools) was highly consistent throughout the study, despite two major floods. Assemblages in individual pools generally were consistent, but there was more variation within pools than at the scale of the entire reach. Throughout the study, most individual pools remained within discrete subsets of the total occupied multivariate space in a principal components analysis based on fish species abundances. Sunfishes (Lepomis spp.) and bass (Micropterus spp.) were more consistent in their distribution among pools than were minnows (Cyprinidae) or a topminnow (Fundulus). There were 25 significant correlations in occurrence of species pairs among stream pools, out of 91 possible comparisons of the 14 most abundant taxa in the reach. Many pools contained assemblages either dominated by large centrarchids or by abundant cyprinids and juvenile centrarchids, but intermediate assemblages also were observed. The dynamics of distribution of fish species and fish assemblages among individual stream pools are likely influenced by a combination of species-specific behaviors and habitat selection, predator constraints on use of individual pools by small fishes, riffles as size-selective barriers to fish movements between pools, dispersal of young-of-the-year fishes, and abiotic phenomena like floods. Individual stream pools appear to be discrete habitat units for fishes, and do represent an appropriate scale for biologically meaningful studies of fish assemblages or their effects on streams.

Use of Ecohydraulic-Based Mesohabitat Classification and Fish Species Traits for Stream Restoration Design

“…The greatest richness and density occurred during the summer and fall periods, with a total of 23 species and average unit densities ranging from 4.9 to 218.6 fish per 100 m 2 . Others found the same seasonal patterns of use where feeding, resting, evasion from predation, and spawning were the dominant trait strategies [172,178,179,193,194,197,198,201,203,[214][215][216]. Schwartz and Herricks (2008) [79] found that feeding strategy could be summarized as: insectivores mainly occupying the pool-front unit, omnivores in the scour pool unit, piscivores in the pool-mid unit, and herbivores in the glide and riffle with raceway unit.…”

“…Within the mesohabitat scale, differential habitat use by fish between pools and riffles has been extensively studied [77,123,175,[193][194][195][196][197][198][199]. It was observed from these studies that pools and riffles locally diversify lotic conditions providing strong abiotic environmental controls on fish distribution and abundance.…”

Aspects structurels et fonctionnels de la biodiversité des peuplements de poissons

“…1). Phylogenetic affiliations have been documented from scales ranging from assemblages of meso-habitats (MATTHEWS et al, 1994) in local communities to régional ichthyofaunas (ROBERTS, 1975 ;LEVEQUE et al, 1990, LUNDBERG, 1993. At the local scale, contemporary ecological factors, rather than historical factors, are of primary interest, although barriers to local dispersai have played a key rôle in some cases (ENDLER, 1982).…”

“…Fish populations inhabiting lowland river Systems are periodically subdivided into local subunits within floodplain lagoons and later reunited with conspecifics from other subunits during annual floods (JUNK et al, 1989 ; WELCOMME, 1979). Most stream fish populations are subdivided into habitat subunits with variable amounts of migration between them (ELLIOT, 1987 ; FRASER & CERRI, 1982 ;MATTHEWS et al, 1994 ;SCHLOSSER, 1982). PULLIAM's (1988) BIDE model may be particularly appropriate for stream fish populations subdivided by mesohabitats.…”

“…1). Phylogenetic affiliations have been documented from scales ranging from assemblages of meso-habitats (MATTHEWS et al, 1994) in local communities to régional ichthyofaunas (ROBERTS, 1975 ;LEVEQUE et al, 1990, LUNDBERG, 1993. At the local scale, contemporary ecological factors, rather than historical factors, are of primary interest, although barriers to local dispersai have played a key rôle in some cases (ENDLER, 1982 physical and biotic environmental variation results in a subdivision or filtering of régional taxonomic pools into nested subsets at successively smaller spatiotemporal scales (KODRIC-BROWN & BROWN, 1993 ;MAHON, 1984 ;MATTHEWS, 1986 ;MERONA, 1981 ;TONN & MAGNUSON, 1982 ;WINEMILLER & LESIE, 1992).…”