The availability of colonizable substrate is an important driver of the temporal dynamics of sessile invertebrates on coral reefs. Increased dominance of algae and, in some cases, sponges has been documented on many coral reefs around the world, but how these organisms benefit from non-colonized substrate on the reef is unclear. In this study, we described the temporal dynamics of benthic organisms on an Indonesian coral reef across two time periods between 2006 and 2017 (2006–2008 and 2014–2017), and investigated the effects of colonizable substrate on benthic cover of coral reef organisms at subsequent sampling events. In contrast with other Indonesian reefs where corals have been declining, corals were dominant and stable over time at this location (mean ± SE percentage cover 42.7 ± 1.9%). Percentage cover of turf algae and sponges showed larger interannual variability than corals and crustose coralline algae (CCA) (P < 0.001), indicating that these groups are more dynamic over short temporal scales. Bare substrate was a good predictor of turf cover in the following year (mean effect 0.2, 95% CI: 0–0.4). Algal cover combined with bare space was a good predictor of CCA cover the following year generally, and of sponge cover the following year but only at one of the three sites. These results indicate that turf algae on some Indonesian reefs can rapidly occupy free space when this becomes available, and that other benthic groups are probably not limited by the availability of bare substrate, but may overgrow already fouled substrates.

中文翻译：

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印度尼西亚珊瑚礁底栖生物的年际变化和年代际稳定性

可定殖基质的可用性是珊瑚礁上无柄无脊椎动物时间动态的重要驱动力。在世界各地的许多珊瑚礁上都记录了藻类和在某些情况下海绵的优势，但这些生物如何从珊瑚礁上的非定殖基质中受益尚不清楚。在这项研究中，我们描述了 2006 年至 2017 年（2006 年至 2008 年和 2014 年至 2017 年）两个时间段内印度尼西亚珊瑚礁上底栖生物的时间动态，并研究了可定殖基质对珊瑚礁生物底栖覆盖的影响。随后的采样事件。与珊瑚一直在减少的其他印度尼西亚珊瑚礁相比，珊瑚在该位置占主导地位并且随着时间的推移保持稳定（平均 ± SE 百分比覆盖 42.7 ± 1.9%）。磷< 0.001），表明这些组在短时间尺度上更具动态性。裸露的基质是次年草坪覆盖率的良好预测指标（平均效应 0.2，95% CI：0-0.4）。藻类覆盖与裸露空间相结合，通常可以很好地预测下一年的 CCA 覆盖，以及下一年的海绵覆盖，但仅在三个地点之一。这些结果表明，一些印度尼西亚珊瑚礁上的草皮藻可以在可用时迅速占据自由空间，并且其他底栖生物群可能不受裸基质可用性的限制，但可能会过度生长已经被污染的基质。