Effects of thermal stress on key processes driving coral-population dynamics
Effects of thermal stress on key processes driving coral-population dynamics
复制标题
热应力对驱动珊瑚种群动态的关键过程的影响
DOI：
10.3354/meps08640
复制
发表时间：
2010
影响因子：
2.5
通讯作者：
R. Woesik
中科院分区：
文献类型：
--
作者：
L. Roth;Semen Koksal;R. Woesik
生态学的一个主要目标是通过量化随时间调节人口密度的关键过程来了解人口动态。任何一种过程的改变都可能改变种群轨迹、遗传构成及其大小频率分布。本研究试图量化 5 个过程中哪一个对日本南部珊瑚礁上的伞形鹿角珊瑚种群动态影响最大：(1) 补充、(2) 定居后死亡率、(3) 生长、(4) 部分死亡率和 (5) 珊瑚群总死亡率。在这里，我们通过热异常（1998 年+1.8°C）跟踪了 1996 年至 2001 年迎风地点和背风地点的珊瑚礁群。我们特别感兴趣的是研究哪些过程对种群动态影响最大。为了预测尺寸频率分布，我们构建了一个包含这 5 个过程的非线性微分方程组。迎风地点的补充量随着时间的推移保持一致，而背风地点在所有深度上的补充率变化更大，并且在 1998 年热异常（多年来一直受到抑制）之后显示出相当大的下降。在所有深度，在热异常期间过渡到更大尺寸等级的菌落比例都高于其他年份。 20 至 30 厘米长的菌落的部分死亡率通常最高，但这并不是热应激的良好指标。在热异常期间，最小和最大的伞形鹿角珊瑚群落的总群落死亡率最为明显，有效地缩小了大小频率分布。敏感性分析显示，珊瑚群总死亡率对珊瑚种群增长率（λ）影响最大，其次是定居后死亡率和补充。量化导致状态变化的种群过程是了解快速变暖的海洋中珊瑚礁动态的先决条件。
A primary goal of ecology is to understand population dynamics by quantifying key pro- cesses that regulate population densities through time. Change to any one process may alter the pop- ulation trajectory, its genetic constitution, and its size-frequency distribution. This study sought to quantify which of the 5 processes — (1) recruitment, (2) post-settlement mortality, (3) growth, (4) par- tial mortality and (5) total colony mortality — most influenced corymbose Acropora coral-population dynamics on reefs in southern Japan. Here we tracked coral reef colonies at a windward site and a leeward site from 1996 to 2001 through a thermal anomaly (+1.8°C in 1998). We were particularly interested in examining which of those processes had the largest effect on population dynamics. To predict size-frequency distributions, we constructed a system of nonlinear differential equations that included those 5 processes. Recruitment at the windward site remained consistent through time, whereas the leeward site had more variable recruitment rates at all depths, and showed a consider- able decrease after the 1998 thermal anomaly that remained suppressed for many years. At all depths, the proportion of colonies transitioning to a larger size class was higher during the thermal anomaly than in other years. Partial mortality was generally highest on 20 to 30 cm length colonies, but was not a good indicator of thermal stress. Total colony mortality was most evident for the small- est and largest corymbose Acropora colonies during the thermal anomaly, effectively narrowing the size-frequency distributions. Sensitivity analyses revealed that total colony mortality had the largest effect on coral-population growth rate (λ), followed by post-settlement mortality and recruitment. Quantifying the population processes that lead to state changes is a prerequisite for understanding reef dynamics in a rapidly warming ocean.