Among-site variability in the stochastic dynamics of East African coral reefs.
Among-site variability in the stochastic dynamics of East African coral reefs.
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作者：
Allen KA;Bruno JF;Chong F;Clancy D;McClanahan TR;Spencer M;Żychaluk K
珊瑚礁是一个动态系统，其组成受到不可预测的生物和非生物因素的高度影响。了解可以对珊瑚礁组成进行长期预测的空间尺度对于指导保护工作至关重要。使用22年的时间序列的底栖生物组成的数据从20个珊瑚礁在肯尼亚和坦桑尼亚海岸，我们开发了贝叶斯向量自回归状态空间模型的珊瑚礁动态，将海洋站点的变化，并量化他们的长期行为。我们估计，如果不存在长期站点变异性，总的长期变异性将大约是其当前值的三分之一。因此，我们的研究结果表明，在珊瑚礁组成的长期变化比时间的变化更有助于网站的变化。单个网站比以前认为的更可预测，基于当前快照的预测是关于长期属性的信息。我们的方法使我们能够确定具有高保护价值的可能气候避难所地点的子集，其中珊瑚覆盖≤0.1（作为硬基质底栖覆盖的比例）的长期概率非常低。分析结果表明，这一概率是最强烈的影响，由底栖生物的网站的变化和网站内的组成部分之间的相互作用。这些研究结果表明，保护措施可能是成功的，在网站规模以及区域规模。
Coral reefs are dynamic systems whose composition is highly influenced by unpredictable biotic and abiotic factors. Understanding the spatial scale at which long-term predictions of reef composition can be made will be crucial for guiding conservation efforts. Using a 22-year time series of benthic composition data from 20 reefs on the Kenyan and Tanzanian coast, we developed Bayesian vector autoregressive state-space models for reef dynamics, incorporating among-site variability, and quantified their long-term behaviour. We estimated that if there were no among-site variability, the total long-term variability would be approximately one-third of its current value. Thus, our results showed that among-site variability contributes more to long-term variability in reef composition than does temporal variability. Individual sites were more predictable than previously thought, and predictions based on current snapshots are informative about long-term properties. Our approach allowed us to identify a subset of possible climate refugia sites with high conservation value, where the long-term probability of coral cover ≤0.1 (as a proportion of benthic cover of hard substrate) was very low. Analytical results show that this probability is most strongly influenced by among-site variability and by interactions among benthic components within sites. These findings suggest that conservation initiatives might be successful at the site scale as well as the regional scale.