Dry and uncovered: Effects of riparian vegetation on abiotic and biotic characteristics of intermittent streams
| Autoři | |
|---|---|
| Rok publikování | 2025 |
| Druh | Další prezentace na konferencích |
| Fakulta / Pracoviště MU | |
| Citace | |
| Popis | Riparian vegetation forms the interface between the terrestrial and aquatic ecosystems and affects many structural and functional stream processes. It can moderate the flow regime, stabilise stream channels, reduce inputs of fine sediments from farmland, and mitigate excessive input of nutrients and micropollutants. Therefore, revegetating riparian zones is a common management action to improve stream conditions. Recently, the flow regime in many streams in the extensive Central Europe region has shifted from perennial to intermittent. The loss of surface water has a dramatic impact on freshwater biota. Species inhabiting intermittent streams require adaptation to survive dry periods. Some of the environmental parameters that are critical for survival in a dry streambed (e.g. temperature, unclogged substrate) can be significantly affected by the presence of riparian buffer strips. Our study investigated the effect of stream bank vegetation on intermittent stream ecosystem structure. We hypothesized that riparian vegetation would stabilise temperature regimes, reduce nutrient inputs, improve channel morphology, and ultimately mitigate the impacts of stream drying on benthic diatom and macroinvertebrate communities. Paired-stream comparisons were conducted between sites with and without well-developed riparian buffer strips. The results showed that streams with riparian vegetation exhibited slightly lower water temperatures, lower total phosphorus concentrations, and significantly higher dissolved oxygen levels. Unbuffered streams received a much higher amount of solar radiation; wetland vegetation was more developed in the streambed, and the bed substrate was covered with a higher amount of fine sediment. Diatom communities from buffered and unbuffered streams largely overlapped. In contrast, macroinvertebrate assemblages displayed distinct differences, with shifts in functional traits reflecting adaptations to temperature, sediment, and flow conditions in streams with riparian buffer strips. Contrary to our hypothesis, riparian buffer strips did not significantly mitigate the impact of stream drying on macroinvertebrate communities. We believe this is due to the overall degradation of unbuffered sites, in which community diversity was already ‘a priori’ limited. Sites with buffer strips are inhabited by species-rich communities experienced more pronounced declines during the dry period than generally uniform communities of unbuffered streams. These findings highlight the importance of riparian vegetation in shaping stream habitats and biodiversity, even though its role in mitigating the effects of stream drying was not supported. The research was supported by Technology Agency of the Czech Republic SS06010258 project. |
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