Original paper

Meiofaunal microhabitat selection in a sandy-bottom river

Rae, J.G.

Abstract

The distribution and abundance of major meiofaunal taxa were investigated at a microhabitat scale in a sandy-bottom lotic point bar in a fourth order South Carolina river to determine environmental factors structuring the community. Small cores were taken monthly and sectioned vertically in 1-cm sections while recording 14 environmental variables, including current, sediment size and organic matter. Seventeen major taxa were found, dominated by Chironomidae and Oligochaeta. Meiofaunal abundance varied significantly across time (average monthly range: 44,000?202,000 individuals m ?2) and depth in the sediment. Partial redundancy analysis (pRDA) indicated a strong relationship between taxon distribution and environmental parameters. Significant variables included depth in the sediment, sediment size and two parameters describing physical location of the sample, distance along the shoreline and from the shore into the river. The major factor was the depth in the sediment at which organisms were found. Significant distributional differences occurred for the 13 most common taxa. The influence of environmental factors on meiofauna community structure was shown even at low taxonomic resolution when examined at a fine habitat scale. There was evidence that different factors were operative in community structuring when examined at different levels of taxonomic resolution.

Keywords

abiotic factorscommunity structuredcaloticmeiofaunamicrohabitatmultivariate analysisprdasediments