SURVIVAL OF AQUATIC INVERTEBRATES IN STREAMBED SEDIMENTS OF INTERMITTENT STREAMS WITH DIFFERENT DURATION OF DRY-PHASE
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| Year of publication | 2017 |
| Type | Conference abstract |
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| Description | Complete loss of surface water flow is a regular event in intermittent streams. This flow cessation is harsh ecological disturbance for aquatic biota, yet a lot of benthic invertebrates can be found in such streams in relatively short period after reflooding. There are two mechanisms of species survival in such environment: high resistance or resilience. The resilience is represented by species ability to survive in refuges (pools, permanent reaches, springs) and recolonize reflooded channel. Resistant taxa are able to survive in dry stream sediments and often form specialized resistant stages (e.g. eggs, diapausing larvae, cysts) which are crucial for long term survival. However, some taxa show the ability to survive shorter dry periods without dormant stages. We examined samples of dry bottom from near-pristine intermittent streams during a summer dry episode when surface water disappeared from their channels. The sediment samples were taken from the surface of stream bottom (maximum depth 15 cm) and at various time after the flow cessation (1 to 90 days). The substrate samples were washed out through the net (mesh size 0.25 mm) and aquatic invertebrates which were still alive were sorted. Differing ability to survive the dry episode was observed within different taxa groups. Survivors’ community composition was compared to the community sampled in wet phase before and after the dry episode to determine which taxa use streambed as a refuge for survival as adults or macroscopic larvae. |
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