Accelerating losses of seagrass meadows motivate the restoration of these highly productive and beneficial ecosystems. Understanding how environmental parameters including depth and temperature affect restoration trajectories through time is key to conserving and restoring seagrass meadows. We used a long-term (12-year), landscape-scale experiment to test the effect of depth on eelgrass (Zostera marina) restoration success and resilience to a marine heat wave (MHW) disturbance. We found that depth was a critical determinant of seagrass restoration success, with no long-term success at sites deeper than 1.5 m below mean sea level (MSL) or shallower than − 0.8 m MSL. Seeds germinated below − 1.5 m MSL, but shoots did not persist, confirming earlier predictions from a hydrodynamic-vegetation model. Depth was also a significant predictor of seagrass resilience following MHW disturbance. Our results suggest that areas of restored seagrass that are resilient to temperature stress exist across an intermediate depth range, excluding the shallowest and deepest portions of the full habitable depth range for restored seagrass. Over the next decades, sea-level rise will likely affect both the habitable area and the resilient area, available for seagrass restoration. However, seagrass enhancement of sediment accretion may at least partially offset sea-level rise rates. As ocean temperatures warm and MHWs occur more frequently, the resilience of seagrass meadows to temperature stress will be of increasing concern. These results suggest that depth is a critical parameter that will help determine what areas are most resilient and therefore most suitable for conservation and restoration.

中文翻译：

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深度影响海草恢复成功和对海洋热浪扰动的恢复能力

海草草甸的加速丧失促使这些高产有益的生态系统的恢复。了解包括深度和温度在内的环境参数如何随时间影响恢复轨迹是保护和恢复海草草甸的关键。我们使用了一个长期（12年）的景观尺度实验来测试深度对鳗e（Zostera marina）的影响）恢复成功以及对海洋热浪（MHW）干扰的恢复能力。我们发现深度是决定海草恢复成功的关键因素，深度低于平均海平面（MSL）1.5 m或深度小于-0.8 m MSL的站点没有长期成功。种子在低于-1.5 m MSL时发芽，但芽没有持续存在，从而证实了水动力-植被模型的早期预测。深度也是MHW干扰后海草弹性的重要预测指标。我们的结果表明，对温度应力具有复原力的恢复海草区域存在于中间深度范围内，但不包括恢复海草整个可居住深度范围的最浅和最深部分。在接下来的几十年中，海平面上升可能会影响可居住区域和弹性区域，可用于海草修复。但是，海草增加沉积物可能会至少部分抵消海平面上升速度。随着海洋温度变暖和MHW的发生更加频繁，海草草甸对温度胁迫的适应性将越来越受到关注。这些结果表明，深度是一个关键参数，将有助于确定哪些区域最有弹性，因此最适合保存和恢复。