荣成马山里海域海草床分布现状及其生态特征

海草床是滨海三大典型生态系统之一，具有极其重要的环境改善、资源养护和减灾防灾等生态功能，亦是全球重要的碳库。2016年8月，通过对荣成马山里海域的现场调查，发现了面积为58.26 hm2的海草床，其海草的种类为红纤维虾形草（Phyllospadix iwatensis）和丛生鳗草（Zostera caespitosa）。红纤维虾形草分布面积为54.50 hm2，占该海域海草床总面积的93.5%，分为北部和南部2个带状区域，平均茎枝密度为（368.0±18.2）shoots/m2，平均生物量（干重，下同）为（297.0±41.5）g/m2。丛生鳗草分布面积为3.76 hm2，占海草床总面积的6.5%，呈现斑块状分布，与红纤维虾形草交错而生，平均茎枝密度为（691.2±17.1）shoots/m2，平均生物量为（534.0±70.7）g/m2。马山里海域海草床主要分布在平均水深为（2.8±0.3） m的以岩礁为主的底质上。海草的生长状况存在显著的空间差异，与水温呈现显著的正相关，与水深和陆源污染物存在显著的负相关。结合历史资料，发现该海域海草床退化现象较严重，其主要威胁因素是人为干扰，主要包括渔业生产、养殖活动和陆源污染输入。建议合理规划周边海域的养殖规模和密度、加强陆源污染物管控和开展海草床生态修复工程，以期为温带海草床的有效保护和科学管理提供参考。

Distribution and ecological characteristics of seagrass bed of Mashanli sea area in Rongcheng

Seagrass bed is one of the three typical coastal ecosystems, which plays an important role in environmental improvement, resource conservation, and mitigation of environment degradation caused by natural disasters. It is also important as a global carbon stock. In August 2016, a field survey was conducted in the sea area of Mashanli of Rongcheng. A seagrass bed with an area of 58.26 hm2 was found, consisting of Phyllospadix iwatensis and Zostera caespitosa meadows. The P. iwatensis meadow was composed of two belt regions south and north of the bed, occupying an area of 54.50 hm2 and accounting for 93.5% of the seagrass bed. The P. iwatensis shoot density was (368.0±18.2) shoots/m2 and the biomass was (297.0±41.5) g/m2. While the Z. caespitosa generally formed dense patches within the P. iwatensis meadows, and occupied an area of 3.76 hm2, accounting for 6.5% of the seagrass bed. The shoot density of Z. caespitosa was (691.2±17.1) shoots/m2, and the biomass was (534.0±70.7) g/m2. The water depth in the seagrass bed was (2.8±0.3) m, and the seabed was mainly rocky, with some sediments covering on the rocky beds. The growth of the seagrasses showed significant spatial variation, which was positively correlated with the water temperature, and negatively correlated with water depth and terrestrial pollutants. By comparing with historical data, it was found that the degradation of seagrass beds in Mashanli sea area was severe. Anthropogenic activities are the main causes of seagrass degradation, including fishing and aquaculture activities, as well as the pollution of land-based sources. Therefore, it is suggested that rationally planning the scale and density of aquaculture in surrounding area, strengthening the control of terrestrial pollutants, and carrying out ecological restoration projects of seagrass beds will promote the effective protection and scientific management of seagrass beds in temperate zone.