Restoration of degraded estuarine oyster reefs typically involves deploying recycled oyster shell. In low‐salinity, low‐predation areas of estuaries, high‐volume shell deployments are known to improve flow conditions and thus oyster survival and growth. It is also hypothesized that the physical structure of restored reefs could suppress foraging by oyster predators in high‐salinity, high‐predation zones. That hypothesis is untested. Given limited resources, it is important to determine how much shell is needed for successful restoration and whether there are diminishing returns in shell addition. In Apalachicola Bay, Florida, we manipulated shell volume on an oyster reef to create three 0.4 ha areas of low (no shell addition), moderate (153 m³ shell), and high (306 m³ shell) habitat structure. We repeated experiments and surveys over 2 years to determine if restoration success increased with habitat structure. Predation on oysters was greater on the non‐shelled area than on the reshelled reefs, but similar between the two reshelled reefs. Oyster larval supply did not differ among the reef areas, but by the end of the experiment, oyster density (per unit area) increased quadratically with habitat structure, plateauing at high levels of structure. Model selection indicated that the most parsimonious explanation for these patterns was that increased habitat structure reduced predation and increased overall recruitment, but that the higher reshelling treatment did not have better outcomes than moderate reshelling. Thus, restoration could be optimized by deploying a moderate amount of shell per unit area.

中文翻译：

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通过添加生物材料减少栖息地恢复的回报：使用河口牡蛎和再生牡蛎壳的测试

恢复退化的河口牡蛎礁通常涉及部署回收的牡蛎壳。在低盐度，低捕食性的河口地区，大量部署贝壳可以改善水流状况，从而改善牡蛎的生存和生长。还假设恢复的礁石的物理结构可以抑制高盐度，高捕食区中牡蛎捕食者的觅食。该假设未经检验。在资源有限的情况下，确定成功恢复所需的外壳数量以及添加外壳的收益是否递减非常重要。在佛罗里达州的阿帕拉奇科拉湾，我们通过控制牡蛎礁上的贝壳体积来创建三个0.4公顷的面积，分别为低（无壳添加），中（153 m ³壳）和高（306 m ^3）贝壳）的栖息地结构。我们在2年内重复进行了实验和调查，以确定恢复成功是否随栖息地结构的增加而增加。在带壳珊瑚礁上，牡蛎的捕食大于带壳珊瑚礁，但两个带壳珊瑚礁之间的相似。牡蛎幼体的供应在各礁区之间没有差异，但是到实验结束时，牡蛎密度（每单位面积）随生境结构呈二次方增加，在高水平的结构上达到平稳。模型的选择表明，对这些模式的最简约的解释是栖息地结构的增加减少了捕食并增加了总体募集，但较高的换壳处理没有比中等程度的换壳更好的结果。因此，可以通过在单位面积上部署适量的外壳来优化恢复。