| Weizhou Island is located in the relatively high latitudes of the northern South China Sea.Under the background of global warming,it may become a refuge for corals in the South China Sea.However,in recent decades,the rapid degradation of the Weizhou Island reef has threatened its ecological function.Therefore,the ecological restoration of Weizhou Island reef has received great attention.Substrate is an important factor affecting coral distribution,but there are few studies on the relationship between substrate and coral growth,and little attention has been paid to the importance of substrate in the ecological restoration of coral reefs.Therefore,this paper explores the relationship between coral distribution and substrate in Weizhou Island,hoping to provide a scientific basis for the protection and ecological restoration of Weizhou Island and other coral reef areas.Focusing on the above scientific issues,this study conducted a systematic investigation and analysis of the Weizhou Island reef from 2018 to 2021:(1)10survey stations,18 ecological sections and 24 substrate sections were set up;(2)A total of 18 line videos with a length of 50 m,330 quadrat photos,109 coral close-up photos were obtained,and 49 substrate collection points were recorded;(3)The obtained data were interpreted and processed,coral ecological data and substrate data were obtained;(4)The effect of substrate on coral distribution in Weizhou Island reef was analyzed.The main conclusions are as follows:(1)The average living coral cover of Weizhou Island reef was 9.94%±7.39%,and the average dead coral cover was 0.32%±0.23%.A total of 48species of 10 families,23 genera and 48 species of corals were identified.Massive and crusting corals were the most common,covering 76.36%and17.06%of the total area respectively.The Shannon-Wiener and Simpson diversity indices were 2.60 and 0.90,respectively,and the richness and evenness indices were 5.91 and 0.70,respectively.The average coral replenishment was2.50±1.70 ind/m~2.Compared with 2015,the average living coral cover increased by 3.92%,and the coral replenishment showed a significant increase.The vigorous protection of the government and units was the main reason for the improvement of the ecological condition of Weizhou Island reef.(2)The area of Weizhou Island reef was about 17.25 km~2,and the abiotic substrate was the main substrate.In general,the substrate of Weizhou Island reef was dominated by reefs,but there are more sand,coral gravel and volcanic rocks nearshore of reef flat,with a small amount of gravel mixed in between.Statistical results showed that the reefs accounted for 46.61%,the substrate of sand,coral gravel,gravel,macroalgae accounted for 25.99%,17.26%,6.48%and 3.87%,respectively,crustose coralline algae and other substrates accounted for 0.15%and 2.28%,respectively.The distribution of substrate in the area of Weizhou Island reef had obvious spatial heterogeneity.(3)The growth and distribution of corals in Weizhou Island were closely related to the type of substrate.Through the analysis,it was found that the reef and crustose coralline algae were conducive to the growth of coral,while coral gravel,macroalgae,gravel and sand were not conducive to the growth and distribution of coral.Corals was distributed most on the reefs,and a small amount of corals was distributed on the volcanic rock,while there is almost no coral distribution on the gravel,coral gravel and sand.Therefore,the substrate had an important impact on the distribution of corals.(4)In view of the importance of the substrate to the protection and restoration of corals,it is suggested that the ecological restoration of Weizhou Island reef should minimize the damage to the reefs caused by human interference,so as to ensure the growth of the original corals;in addition,ecological restoration should choose areas with more reefs as much as possible to ensure the effect of ecological restoration. |
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