| |
Presented at the NABS Annual meeting, Vancouver, British Columbia, 2004
in Community structure 1
Temporal dynamics of a headwater stream meiofaunal community
A. Arnold1, M. Dobson1, and A. Robertson2. 1Department of Environmental & Geographical Sciences, Manchester Metropolitan University, Manchester, M1 5GD,UK, 2School of Life Sciences, University of Surrey Roehampton, London, SW15 3SN, UK
Headwater streams are known to be highly responsive to changing environmental conditions. Abiotic processes structuring these habitats are important in influencing temporal population and taxonomic turnover of small invertebrates (meiofauna — size: 50–500µm). However it is unclear which abiotic variables dominate invertebrate turnover and what their relative taxonomic responses are. In order to assess the influence of naturally fluctuating abiotic conditions on invertebrate populations, fortnightly physicochemical measurements and surber samples of invertebrates (taxa size range — 50µm to >500µm) were taken from the upper 10cm of a headwater streambed over a 12 month period. On all sampling occasions invertebrate abundances were dominated by meiofauna with normally > 70% of the taxa consisting of permanent meiofauna. Although macroinvertebrate taxa and populations fluctuated little in response to abiotic variation, distinct seasonal peaks in taxonomic and population turnover were evident in the meiofauna. In early summer and autumn, flood events were associated with increasing population and taxa turnover. This study indicates meiofauna were not only numerically dominant but appeared to be more sensitive to hydrological fluctuations than macroinvertebrates. It also suggests that the differing responses of macroinvertebrates and meiofauna to their environment do not make them good substitutes for monitoring each other.
|
|
