A framework for identifying and characterising coral reef "oases" against a backdrop of degradation
A framework for identifying and characterising coral reef "oases" against a backdrop of degradation
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DOI：
10.1111/1365-2664.13179
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发表时间：
2018-11-01
影响因子：
5.7
通讯作者：
Toth, Lauren T.
中科院分区：
文献类型：
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作者：
Guest, James R.;Edmunds, Peter J.;Toth, Lauren T.
1.人类活动导致了大范围的生态退化，但退化的严重程度在空间上是不均匀的，这是由于某些地区对干扰的抵抗、逃避或反弹.我们开发了一个框架，用于使用长期监测数据识别珊瑚礁区域内的绿洲。我们计算了珊瑚覆盖率的标准化估计值（z分数），以区分与区域平均值正偏离的地点。我们还使用珊瑚覆盖的变异系数（CV）来量化绿洲的时间变化，并区分绿洲的类型。我们估计了“珊瑚钙化能力”（CCC），衡量珊瑚群落产生碳酸钙结构的能力，并测试了这一指标与珊瑚覆盖率z分数之间的关联。我们说明了我们的Z-分数的建模框架内的方法，提取Z-分数和CV模拟数据的基础上四个广义的珊瑚覆盖的轨迹。然后，我们采用的方法，从长期的珊瑚礁监测方案在四个重点地区在太平洋（夏威夷群岛和莫雷阿，法属波利尼西亚）和西大西洋（佛罗里达键和圣约翰，美属维尔京群岛）的时间序列数据。在分析的123个地点中，有38个在珊瑚覆盖率中位数方面的z得分为正，并被归类为绿洲。合成与应用。我们的框架为生态系统管理者提供了一个有价值的工具，通过识别退化地区的“绿洲”进行保护。通过评估状态变化的轨迹（例如，珊瑚覆盖）之间的绿洲，我们的方法可能有助于确定生态系统条件的空间变异的机制。增加机械的理解可以指导特定地点的管理是否应该强调保护，缓解或恢复。经验数据的分析表明，我们的珊瑚礁绿洲起源于逃避或抵抗干扰，虽然有些网站表现出很高的恢复能力，而其他的候选人恢复。最后，我们对珊瑚礁状况的测量（即，珊瑚覆盖率的中位z分数）与珊瑚钙化能力呈正相关，这表明我们的方法确定的绿洲也是生态功能的一个关键组成部分。
1. Human activities have led to widespread ecological decline; however, the severity of degradation is spatially heterogeneous due to some locations resisting, escaping, or rebounding from disturbances.2. We developed a framework for identifying oases within coral reef regions using long-term monitoring data. We calculated standardised estimates of coral cover (z-scores) to distinguish sites that deviated positively from regional means. We also used the coefficient of variation (CV) of coral cover to quantify how oases varied temporally, and to distinguish among types of oases. We estimated "coral calcification capacity" (CCC), a measure of the coral community's ability to produce calcium carbonate structures and tested for an association between this metric and z-scores of coral cover.3. We illustrated our z-score approach within a modelling framework by extracting z-scores and CVs from simulated data based on four generalized trajectories of coral cover. We then applied the approach to time-series data from long-term reef monitoring programmes in four focal regions in the Pacific (the main Hawaiian Islands and Mo'orea, French Polynesia) and western Atlantic (the Florida Keys and St. John, US Virgin Islands). Among the 123 sites analysed, 38 had positive z-scores for median coral cover and were categorised as oases.4. Synthesis and applications. Our framework provides ecosystem managers with a valuable tool for conservation by identifying "oases" within degraded areas. By evaluating trajectories of change in state (e.g., coral cover) among oases, our approach may help in identifying the mechanisms responsible for spatial variability in ecosystem condition. Increased mechanistic understanding can guide whether management of a particular location should emphasise protection, mitigation or restoration. Analysis of the empirical data suggest that the majority of our coral reef oases originated by either escaping or resisting disturbances, although some sites showed a high capacity for recovery, while others were candidates for restoration. Finally, our measure of reef condition (i.e., median z-scores of coral cover) correlated positively with coral calcification capacity suggesting that our approach identified oases that are also exceptional for one critical component of ecological function.