Data from: Scale‐dependent spatial patterns in benthic communities around a tropical island seascape

Understanding and predicting patterns of spatial organization across ecological communities is central to the field of landscape ecology, and a similar line of inquiry has begun to evolve sub‐tidally among seascape ecologists. Much of our current understanding of the processes driving marine community patterns, particularly in the tropics, has come from small‐scale, spatially‐discrete data that are often not representative of the broader seascape. Here we expand the spatial extent of seascape ecology studies and combine spatially‐expansive in situ digital imagery, oceanographic measurements, spatial statistics, and predictive modeling to test whether predictable patterns emerge between coral reef benthic competitors across scales in response to intra‐island gradients in physical drivers. We do this around the entire circumference of a remote, uninhabited island in the central Pacific (Jarvis Island) that lacks the confounding effects of direct human impacts. We show, for the first time, that competing benthic groups demonstrate predictable scaling patterns of organization, with positive autocorrelation in the cover of each group at scales < ~1 km. Moreover, we show how gradients in subsurface temperature and surface wave power drive spatially‐abrupt transition points in group dominance, explaining 48 – 84% of the overall variation in benthic cover around the island. Along the western coast, we documented ten times more sub‐surface cooling‐hours than any other part of the coastline, with events typically resulting in a drop of 1 – 4°C over a period of < 5 hr. These high frequency temperature fluctuations are indicative of upwelling induced by internal waves and here result in localized nitrogen enrichment (NO2 + NO3) that promotes hard coral dominance around 44% of the island's perimeter. Our findings show that, in the absence of confounding direct human impacts, the spatial organization of coral reef benthic competitors are predictable and somewhat bounded across the seascape by concurrent gradients in physical drivers.

理解并预测生态群落的空间组织模式，是景观生态学领域的核心研究议题；类似的研究思路也正逐渐在潮下带海景观生态学家群体中兴起。当前学界对驱动海洋群落格局的过程（尤以热带海域为甚）的认知，大多源自小尺度、空间离散的观测数据，而这类数据往往无法代表更广阔的海景观尺度。本研究拓展了海景观生态学研究的空间范围，结合大范围原位（in situ）数字影像、海洋学观测数据、空间统计学方法与预测模型，旨在验证珊瑚礁底栖竞争类群（benthic competitors）是否会响应岛内陆物理驱动因子的梯度，在不同尺度下呈现可预测的组织模式。研究区域选取中太平洋偏远无人岛贾维斯岛（Jarvis Island）的完整岸线，该区域不存在直接人类活动的混杂影响。本研究首次证实：底栖竞争类群展现出可预测的空间组织尺度规律，当尺度小于约1公里时，各类群的盖度呈现正自相关性。此外，本研究揭示了次表层水温与表层波浪能的梯度如何驱动类群优势度的空间突变边界，该模型可解释该岛周边底栖盖度总变异的48%至84%。在该岛西海岸，我们记录到的次表层降温时长是其他岸段的十倍，此类降温事件通常可在5小时内使水温下降1至4摄氏度。这类高频温度波动由内波引发的上升流所致，可造成局域氮富集（NO₂+NO₃），进而在该岛约44%的岸线范围内促进造礁石珊瑚占据优势。本研究结果表明：在不受直接人类活动混杂影响的前提下，珊瑚礁底栖竞争类群的空间组织模式具备可预测性，且整体上受海景观中同步变化的物理驱动因子梯度所约束。