Ecology & Biodiversity, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands.
Department of Bioscience, Aarhus University, Vejlsøvej 25, P. O. Box 314, DK-8600, Silkeborg, Denmark.
Glob Chang Biol. 2015 Aug;21(8):2881-90. doi: 10.1111/gcb.12921. Epub 2015 Jun 8.
A future higher risk of severe flooding of streams and rivers has been projected to change riparian plant community composition and species richness, but the extent and direction of the expected change remain uncertain. We conducted a meta-analysis to synthesize globally available experimental evidence and assess the effects of increased flooding on (1) riparian adult plant and seedling survival, (2) riparian plant biomass and (3) riparian plant species composition and richness. We evaluated which plant traits are of key importance for the response of riparian plant species to flooding. We identified and analysed 53 papers from ISI Web of Knowledge which presented quantitative experimental results on flooding treatments and corresponding control situations. Our meta-analysis demonstrated how longer duration of flooding, greater depth of flooding and, particularly, their combination reduce seedling survival of most riparian species. Plant height above water level, ability to elongate shoots and plasticity in root porosity were decisive for adult plant survival and growth during longer periods of flooding. Both 'quiescence' and 'escape' proved to be successful strategies promoting riparian plant survival, which was reflected in the wide variation in survival (full range between 0 and 100%) under fully submerged conditions, while plants that protrude above the water level (>20 cm) almost all survive. Our survey confirmed that the projected increase in the duration and depth of flooding periods is sufficient to result in species shifts. These shifts may lead to increased or decreased riparian species richness depending on the nutrient, climatic and hydrological status of the catchment. Species richness was generally reduced at flooded sites in nutrient-rich catchments and sites that previously experienced relatively stable hydrographs (e.g. rain-fed lowland streams). Species richness usually increased at sites in desert and semi-arid climate regions (e.g. intermittent streams).
未来溪流和河流严重洪水的风险增加预计将改变河岸植物群落组成和物种丰富度，但预期变化的程度和方向仍不确定。我们进行了荟萃分析，以综合全球现有实验证据，并评估增加洪水对（1）河岸成年植物和幼苗存活率、（2）河岸植物生物量和（3）河岸植物物种组成和丰富度的影响。我们评估了哪些植物特征对河岸植物物种对洪水的响应至关重要。我们从 ISI Web of Knowledge 中确定并分析了 53 篇论文，这些论文提供了关于洪水处理和相应对照情况的定量实验结果。我们的荟萃分析表明，洪水持续时间更长、洪水深度更大，特别是两者的结合，会降低大多数河岸物种的幼苗存活率。水位以上的植物高度、伸长枝条的能力和根孔隙的可塑性对于长时间洪水期间成年植物的存活和生长至关重要。“休眠”和“逃避”都被证明是促进河岸植物存活的成功策略，这反映在完全淹没条件下的存活率变化很大（全范围在 0%到 100%之间），而高出水面的植物（>20 厘米）几乎全部存活。我们的调查证实，洪水期持续时间和深度的预计增加足以导致物种转移。这些转移可能会增加或减少河岸物种丰富度，具体取决于集水区的养分、气候和水文状况。在养分丰富的集水区和先前经历相对稳定水文学（例如雨养低地溪流）的洪泛区，物种丰富度通常会降低。在沙漠和半干旱气候区（例如间歇性溪流）的洪泛区，物种丰富度通常会增加。
