Table_1_A Hotspot in the Romanian Black Sea: Eelgrass Beds Drive Local Biodiversity in Surrounding Bare Sediments.docx

Ecosystem engineers create habitat and provide conditions otherwise unavailable for the development of diverse communities. In marine soft-bottoms in particular, the biodiversity sustained by a matrix of relatively uniform sediments can be drastically enhanced by the presence of ecosystem engineers such as seagrasses. Unfortunately, the influence of seagrass meadows on the diversity of surrounding sediments is often unrecognized in spite of its importance, especially in coastlines exposed to multiple sources of pollution. This study examined composition and diversity associated with a bed of Zostera noltei Hornemann, 1832, and its surrounding bare sediments in a highly urbanized coastal area of the Romanian Black Sea. Dissimilarity levels were quantified and key species driving the differences between uniform (bare) and complex (eelgrass) sedimentary habitats were identified. 48 taxa were collected and counted, with epifaunal and infaunal species each accounting for nearly half of that diversity. Abundance, richness and diversity were strikingly higher in eelgrass-associated sediments, a difference driven primarily by various species of snails, crustaceans, polychaetes and bivalves. Between-habitat differences remained significant even after the removal of epifaunal species and each dataset undergoing strong data transformation. These results suggest that even small eelgrass beds, located in the vicinity of multiple sources of stress, can act as hotspots and make a substantial contribution to local benthic diversity.

生态系统工程师（ecosystem engineer）可构建生境，并为多样群落的发育提供原本无法获取的生存条件。尤其在海洋软底质生境中，由相对均一沉积物基质维持的生物多样性，可因海草等生态系统工程师的存在而大幅提升。遗憾的是，尽管海草床（seagrass meadow）对周边沉积物多样性的影响至关重要，但该影响常被忽视，在受多种污染源影响的海岸带尤为如此。本研究针对罗马尼亚黑海沿岸一处高度城市化的沿海区域，对矮大叶藻（Zostera noltei Hornemann, 1832）床及其周边裸露沉积物的群落组成与多样性展开了调研。研究量化了群落组成的差异程度，并明确了驱动均一（裸露）与复杂（海草）沉积生境间差异的关键物类。本次调研共采集并计数了48个分类单元（taxon），其中表栖动物（epifauna）与内栖动物（infauna）各占该多样性的近一半。与海草关联的沉积物中，个体丰度、物种丰富度及多样性均显著更高，该差异主要由螺类、甲壳类、多毛类及双壳类的多个物类所驱动。即便移除表栖动物物种并对各数据集进行强数据转换后，生境间的差异依然显著。上述结果表明，即便位于多种胁迫源附近的小型海草床，也可作为生物多样性热点（biodiversity hotspot）区域，对当地底栖（benthic）生物多样性做出显著贡献。