Disturbances on coral reefs—which are increasing in intensity and frequency—generate material legacies. These are commonly in the form of rubble beds, which depend on rubble stability and/or binding to facilitate coral recruitment and recovery. Yet, our understanding of rubble stability and binding dynamics across environmental gradients is limited. Characterising and categorising rubble material legacies in context of their likely recovery trajectory is imperative to the effective deployment of active intervention strategies used to restore degraded reefs, such as rubble stabilisation, coral outplanting and larval seeding techniques. We quantified rubble characteristics across environmental gradients on the Great Barrier Reef. The likelihood of rubble stability and binding increased with rubble length and rubble bed thickness, and rubble length was a good predictor of bed thickness and rubble branchiness. Thin rubble bed profiles (< ~10 cm depth), those with small, unbranched rubble pieces (< ~10 cm length), and beds at the base of sloped rubble screes, had lower stability and binding likelihoods. These kinds of beds are expected to persist with low recovery prospects, and could be good candidates for rubble stabilisation interventions. Thicker rubble beds with larger, branched rubble pieces tended to exhibit higher stability and binding likelihoods. However, these beds had nuanced effects on coral cover, and interventions may still be necessary where competition is high, for example from macroalgae. A rapid assessment of rubble length—while also considering shelf location, geomorphic zone, slope angle and underlying substrate—can indicate the potential direction of a rubble bed's recovery trajectory. Our findings have been summarised into a rapid rubble bed assessment tool available in the Supporting Information, that can be incorporated into current reef monitoring to optimize prioritisation of intervention strategies at disturbed sites.

中文翻译：

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珊瑚礁的物质遗留问题：碎石长度和碎石床厚度是碎石床恢复的关键驱动因素


对珊瑚礁的干扰——强度和频率都在增加——会产生物质遗留问题。这些通常以碎石床的形式出现，它们依赖于碎石的稳定性和/或结合力，以促进珊瑚的补充和恢复。然而，我们对碎石稳定性和跨环境梯度的结合动力学的理解是有限的。根据碎石材料遗留物可能的恢复轨迹对其特征和分类对于有效部署用于恢复退化珊瑚礁的积极干预策略至关重要，例如碎石稳定、珊瑚移栽和幼虫播种技术。我们量化了大堡礁环境梯度中的碎石特征。碎石稳定性和结合的可能性随着碎石长度和碎石床厚度的增加而增加，碎石长度是碎石层厚度和碎石枝度的良好预测指标。较薄的碎石层剖面（x3C ~10 cm深）、具有小而无分支的碎石块（x3C ~10 cm长）以及位于倾斜碎石碎石碎石底部的层，具有较低的稳定性和结合可能性。预计这类床将持续存在，恢复前景很低，可能是瓦砾稳定干预措施的良好候选者。较厚的碎石层和较大的分枝碎石块往往表现出更高的稳定性和结合可能性。然而，这些床对珊瑚覆盖率有细微的影响，在竞争激烈的地方，例如来自大型藻类的地方，可能仍然需要干预。快速评估碎石长度，同时还要考虑大陆架位置、地貌带、坡度角和底层基质，可以指示碎石床恢复轨迹的潜在方向。 我们的研究结果已总结为支持信息中提供的快速碎石床评估工具，该工具可以纳入当前的珊瑚礁监测，以优化受干扰地点干预策略的优先级。