Determining Coral Density Thresholds for Identifying Structurally Complex Vulnerable Marine Ecosystems in the Deep Sea
Determining Coral Density Thresholds for Identifying Structurally Complex Vulnerable Marine Ecosystems in the Deep Sea
复制标题
确定珊瑚密度阈值以识别深海结构复杂的脆弱海洋生态系统
DOI：
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发表时间：
2020
影响因子：
3.7
通讯作者：
M. Clark
中科院分区：
文献类型：
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作者：
A. Rowden;T. Pearman;D. Bowden;O. Anderson;M. Clark
脆弱的海洋生态系统面临深海拖网捕捞影响的风险。迄今为止，查明公海渔业管理区是否存在脆弱海洋生态系统主要依靠存在记录或脆弱海洋生态系统指示分类群的生境适宜性模型（例如，石珊瑚物种Solenosmilia variabilis邓肯，1873年）作为脆弱海洋生态系统出现的代用指标（例如，冷水珊瑚礁）。然而，指示生物分类群的存在或预测存在并不一定等同于脆弱海洋生态系统的出现。很少有人试图确定脆弱海洋生态系统指示分类群的密度阈值，这些阈值与“显著集中”有关，而根据目前确定结构复杂脆弱海洋生态系统的标准，这种“显著集中”支持相关分类群的“高度多样性”（粮农组织，2009年）。如果不知道这些阈值，脆弱海洋生态系统的识别将继续是主观的，从而阻碍为脆弱海洋生态系统设计有效空间管理措施的努力。为了解决这个问题，我们使用来自新西兰路易斯维尔海山链的海底视频和静止图像数据来模拟活Solenosmilia variabilis珊瑚头的密度之间的关系，以及活珊瑚和死珊瑚基质的覆盖率，以及其他表生动物类群的数量。分析进行了三个空间尺度; 50和25平方米的视频，2平方米的静止。模型曲线表现出初始陡峭的积极响应，达到阈值的数量活珊瑚头在0.11米-2（50平方米），0.14米-2（25平方米），和0.85米-2（2平方米）。活珊瑚和死珊瑚的覆盖率与相关分类群的数量呈正相关，在所有空间尺度上（24.5-28%），覆盖率高达约30%。我们结合过去和今后为确定脆弱海洋生态系统而制定标准的努力，讨论这些结果。
Vulnerable marine ecosystems (VMEs) are at risk from the impacts of deep-sea trawling. Identifying the presence of VMEs in high seas fisheries management areas has to date relied mainly on presence records, or on habitat suitability models of VME indicator taxa (e.g., the stony coral species Solenosmilia variabilis Duncan, 1873) as proxies for the occurrence of VMEs (e.g., cold-water coral reefs). However, the presence or predicted presence of indicator taxa does not necessarily equate to the occurrence of a VME. There have been very few attempts to determine density thresholds of VME indicator taxa that relate to a “significant concentration” which supports a “high diversity” of associated taxa, as per the current criterion for identifying structurally complex VMEs (FAO, 2009). Without knowing such thresholds, identifications of VMEs will continue to be subjective, impeding efforts to design effective spatial management measures for VMEs. To address this issue, we used seafloor video and still image data from the Louisville Seamount Chain off New Zealand to model relationships between the densities of live Solenosmilia variabilis coral heads, as well as percent cover of live and dead coral matrix, and the number of other epifauna taxa present. Analyses were conducted at three spatial scales; 50 and 25 m2 for video, and 2 m2 for stills. Model curves exhibited initial steep positive responses reaching thresholds for the number of live coral heads at 0.11 m–2 (50 m2), 0.14 m–2 (25 m2), and 0.85 m–2 (2 m2). Both live and dead coral cover were positively correlated with the number of associated taxa up to about 30% cover, for all spatial scales (24.5–28%). We discuss the results in the context of past and future efforts to develop criteria for identifying VMEs.