Kretz Lena, Koll Katinka, Seele-Dilbat Carolin, van der Plas Fons, Weigelt Alexandra, Wirth Christian
Life science, Systematic Botany and Functional Biodiversity, Leipzig University, Leipzig, Germany.
Department Conservation Biology, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany.
PLoS One. 2021 Mar 18;16(3):e0248320. doi: 10.1371/journal.pone.0248320. eCollection 2021.
Sediment retention is a key ecosystem function provided by floodplains to filter sediments and nutrients from the river water during floods. Floodplain vegetation is an important driver of fine sediment retention. We aim to understand which structural properties of the vegetation are most important for capturing sediments. In a hydraulic flume experiment, we investigated this by disentangling sedimentation on and underneath 96 vegetation patches (40 cm x 60 cm). We planted two grass and two herb species in each patch and conducted a full-factorial manipulation of 1) vegetation density, 2) vegetation height, 3) structural diversity (small-tall vs tall-tall species combinations) and 4) leaf pubescence (based on trait information). We inundated the vegetation patches for 21 h in a flume with silt- and clay-rich water and subsequently measured the amount of accumulated sediment on the vegetation and on a fleece as ground underneath it. We quantified the sediment by washing it off the biomass and off the fleece, drying the sediment and weighting it. Our results showed that all manipulated vegetation properties combined (vegetation density and height, and the interaction of structural diversity and leaf pubescence) explained sedimentation on the vegetation (total R2 = 0.34). The sedimentation underneath the vegetation was explained by the structural diversity and the leaf pubescence (total R2 = 0.11). We further found that vegetation biomass positively affected the sedimentation on and underneath the vegetation. These findings are crucial for floodplain management strategies with the aim to increase sediment retention. Based on our findings, we can identify management strategies and target plant communities that are able to maximize a floodplain's ability to capture sediments.
沉积物截留是洪泛平原所提供的一项关键生态系统功能，即在洪水期间从河水中过滤沉积物和养分。洪泛平原植被是细颗粒沉积物截留的重要驱动因素。我们旨在了解植被的哪些结构特性对于捕获沉积物最为重要。在一项水槽实验中，我们通过解开96个植被斑块（40厘米×60厘米）上及其下方的沉积作用来对此进行研究。我们在每个斑块中种植了两种草和两种草本植物，并对以下因素进行了全因子操作：1）植被密度，2）植被高度，3）结构多样性（矮-高与高-高物种组合）以及4）叶毛被（基于性状信息）。我们在水槽中用富含淤泥和粘土的水淹没植被斑块21小时，随后测量植被上以及其下方作为地面的羊毛毡上积累的沉积物量。我们通过将沉积物从生物量和羊毛毡上冲洗下来、干燥沉积物并称重来对沉积物进行量化。我们的结果表明，所有操作的植被特性综合起来（植被密度和高度，以及结构多样性和叶毛被的相互作用）解释了植被上的沉积作用（总R² = 0.34）。植被下方的沉积作用由结构多样性和叶毛被来解释（总R² = 0.11）。我们还进一步发现，植被生物量对植被上及其下方的沉积作用有积极影响。这些发现对于旨在增加沉积物截留的洪泛平原管理策略至关重要。基于我们的发现，我们可以确定能够最大化洪泛平原捕获沉积物能力的管理策略和目标植物群落。
