Benthic meiofauna assemblage structure of headwater streams: density and distribution of taxa relative to substrate size |
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Authors: | Andrea J Radwell Arthur V Brown |
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Institution: | (1) Department of Biological Sciences, University of Arkansas, Sci-Eng Room 601, Fayetteville, AR 72701, USA |
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Abstract: | Permanent meiofauna taxa and portions of the population of other invertebrates that are temporarily in the meiofauna size
class are often precluded from stream studies and assessments. This study was designed to determine the identity, density,
and distribution of major meiofauna taxa relative to substrate size in a set of similar headwater streams. Using a coring
technique, meiofauna (80 μm–1 mm) and substrate samples were collected from 11 Ozark headwater streams in the Boston Mountain
ecoregion of Arkansas, USA. Mean meiofauna density among streams was 1739 ± 436 organisms per l. Permanent meiofauna taxa
(Copepoda, Cladocera, Ostracoda, Rotifera, Nematoda, Hydrachnida, and Tardigrada) comprised 22.5% of the organisms collected
with a mean density of 394 ± 233 organisms per l; temporary meiofauna taxa (Oligochaeta, Turbellaria, Hydroidea, Chironomidae,
Ephemeroptera, and other insects) comprised the remainder with a density of 1346 ± 308 organisms per l. Chironomidae was the
most numerous temporary meiofauna taxon, and Hydrachnida was the most numerous permanent taxon. Streams were found to differ
significantly in substrate composition and densities of major taxonomic categories. Substrate size was found to predict densities
for most of these taxonomic categories. Meiofauna patchiness was reflected in high variability within streams. Canonical correspondence
analysis revealed positive associations between Copepoda and Nematoda and silt, and between Copepoda, Nematoda, and Rotifera
and fine sand. Hydrachnida and Rotifera were negatively associated with silt and coarse sand, respectively. The potential
value of inclusion of meiofauna in stream environmental assessments is discussed. |
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Keywords: | Lotic freshwater meiofauna Permanent meiofauna Sediment Stream assessment Temporary meiofauna |
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