人为物理干扰对海草群落及大型底栖动物的生态影响

Ecological Effects of Physical Disturbance on Seagrass Community and Associated Macrobenthos

关键词:  潮间带海草  喜盐草  裸体方格星虫  贝类/星虫采集  使用高压水枪  海草保护

Key words:  intertidal seagrass  Halophila ovalis  Sipunculus nudus  clam/sandworm harvesting  using pumping method  seagrass conservation

摘要:

[目的]探讨使用高压水枪以及连片集中式人工挖掘方式的人为物理干扰在海草区采集滩涂经济动物的行为对海草群落及底栖动物造成的生态影响。[方法]对广西竹林海草床5种生境展开调查和采样:①未受人为物理干扰的海草区;②未受人为物理干扰的裸滩;③刚刚遭受人工挖掘影响的海草区;④刚刚遭受高压水枪冲击后的海草区;⑤遭受高压水枪冲击5 d后的海草区。计算分析各生境海草群落的覆盖度、直立茎密度和生物量,以及大型底栖动物的栖息密度、生物量和生物多样性指数。[结果]人为物理干扰短期内显著地降低了海草床的覆盖度、栖息密度和生物量,改变了大型底栖动物的优势种,同时降低了海草床大型底栖动物多样性指数、物种丰富度指数、栖息密度和生物量。[结论]人为物理干扰(高压水枪的使用等)短期内对海草群落和大型底栖动物群落都有较大的负面生态影响,长期的生态效应有待进一步的研究。建议执法部门加强对滩涂采集经济动物方式的管理,尤其是关于高压水枪的使用问题。

Abstract:

[Objective] This paper explores the ecological effects of human physical disturbances (both contiguous artificial mining and using pumping method for harvesting intertidal economic animals) on the seagrass community and associated macrobenthos.[Methods] Seagrass samples and the associated macrobenthos samples in the five different habitats (the undisturbed seagrass bed, the undisturbed barren tidal flats, the artificial mining disturbed seagrass bed, the newly pumping disturbed seagrass bed and the 5 d pumping disturbed seagrass bed)in Zhulin meadows were collected and analyzed in the laboratory.Biodiversity indices of macrobenthos for each habitat were calculated.[Results] Our results showed that human physical disturbances had significantly decreased the coverage, shoot density and biomass of seagrass in the study site, and also significantly reduced the density, biomass and biodiversity indices in the associated macrobenthos. Furthermore, the dominant species of the macrobenthos had been altered after the physical disturbances.[Conclusion] Artificial physical disturbances (the use of the pumping method in the intertidal clam/sandworm harvesting) have a significant negative ecological impact on the seagrass community and the associated macrobenthos in the short term. However, its long-term effect deserves further study. It is recommended that law enforcement agencies strengthen the management of harvesting the intertidal economic macrobenthos, in particular with regard to the use of water pump.