Streambed sediment as an invertebrate refuge during the long-term drying
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| Year of publication | 2018 |
| Type | Appeared in Conference without Proceedings |
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| Description | Climate change brings to many regions more frequent stream drying therefore we studied survival mechanisms of aquatic macroinvertebrate communities on gradient of dry phase duration. We have repeatedly sampled dry streambed sediments from 10 intermittent streams (2-3 Strahler order) in Czech Republic to identify changes in structure of benthic invertebrate community composition related to dry phase duration of 1-151 days. We found significant changes in the community composition connected to number of dry days before sampling date: abundances of surviving aquatic invertebrates (sorted alive from sediment) were gradually decreasing, less resistant taxa vanishing, whilst semi-aquatic and terrestrial species successively enriched the community composition. This turn-over pattern may serve as a tool for drying period estimation. Even when water flow ceased the streambed retains remarkable proportion of water content (ca 5-20 %) thus this residual moisture enables survival of some aquatic invertebrates. Some aquatic macroinvertebrates are able to survive a long dry period in moist streambed which serves as a refuge. Invertebrates can use either specific drought resistant stages (e.g. eggs and cysts) or can simply persist as larvae or adults. We confirmed presence of resistant eggs in dry streambed by two months laboratory cultivation of re-watered and aerated sediments. During the cultivation we found larvae and emerging adults of species which were even not detected in dry sediment immediately after the sampling. We also investigated sediments from different mesohabitats which revealed evident dissimilarities in their community composition. Thus it is apparent that habitat diversity of dry streambed plays an important role in invertebrate survival and in consequent recolonisation after flow resumption. In study was used data from BIODROUGHT project (www.biodrought.eu) and was supported by INTER-COST project (LTC17017). |
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