涠洲岛造礁石珊瑚群落变化特征及其环境影响因子

Abstract

以涠洲岛造礁石珊瑚群落为研究对象，分析其群落物种组成、多样性、Raunkiaer频度和种间Spearman轶相关，探讨群落组成与水环境因子的相关性，并结合近10年来涠洲岛造礁石珊瑚变化情况，找出涠洲岛造礁石珊瑚群落的主导影响因素。结果表明：（1）近10年来涠洲岛造礁石珊瑚覆盖率显著降低，珊瑚形态组成趋于块状化，尽管珊瑚群落多样性较高，但群落分布较松散，群落结构较不稳定，部分优势种种间竞争较激烈。（2）悬浮物含量是影响石珊瑚群落最显著的环境因子。石珊瑚优势种群在不同水深中分布差异显著，泥沙覆盖率、营养盐对不同石珊瑚种群影响差异较大，大型海藻覆盖率在局部区域对优势珊瑚形成较强的竞争关系。（3）营养盐和泥沙沉积物的增加与涠洲岛近海养殖业及生活排污、海岸工程及海岸侵蚀密切相关。;For the Weizhou Island, which is geographically independent, the human-induced influence is more significant to the rapid degradation of its coral reef ecosystems. the identification of dominant influencing factors on different temporal scales remains a challenge for the local aquatic environment. It is, therefore, essential to explore the ecological status of the coral reefs and the potential threats in Weizhou Island. The primary aim of this study is to explore the dominant influencing factors for the degradation of the scleractinian coral community in Weizhou Island within the 10 years of 2009-2019. To this end, the species composition, diversity, Raunkiaer frequency and Spearman correlation of the community were analyzed. The correlations between the community composition and environmental variations of water were further discussed. The identification of the dominant factors was performed through analyzing the ecological changes of scleractinian coral community in Weizhou Island over 10 years. Results demonstrated that, the coverage of scleractinian coral in the study area significantly decreased, with the changes of the coral reef in morphology, e.g., block. It was noted that, the diversity of the scleractinian coral community was relatively high, but scarred distribution in space of the coral community was observed. Furthermore, the ecological structure was unstable due to the intense competition among some dominant species. It was believed that the high loads of suspended sediments were the most important factor to affect the ecological characteristics of the scleractiniane coral community in Weizhou Island. The spatial distribution of the dominant species was highly related to the water depths, whilst the sediment coverages and nutrient sources significantly affected the diversity of coral populations. Further, relatively strong competition between local large algae and the dominant species of coral reefs was observed. We also observed that the environmental factors, nutrients and sediments, were closely correlated with the aquaculture, human sewage, coastal engineering, coastal erosion, etc.