Data from: Life stage and species identity affect whether habitat subsidies enhance or simply redistribute consumer biomass

1. Quantifying the response of mobile consumers to changes in habitat availability is essential for determining the degree to which population-level productivity is habitat limited rather than regulated by other, potentially density-independent factors. 2. Over landscape scales, this can be explored by monitoring changes in density and foraging as habitat availability varies. As habitat availability increases, densities may: (1) decrease (unit-area production decreases; weak habitat limitation); (2) remain stable (unit-area production remains stable; habitat limitation); or (3) increase (unit-area production increases; strong habitat limitation). 3. We tested the response of mobile estuarine consumers over five months to changes in habitat availability in situ by comparing densities and feeding rates on artificial reefs that were or were not adjacent to neighboring artificial reefs or nearby natural reefs). 4. Using either constructed or natural reefs to manipulate habitat availability, we documented three-fold density decreases among juvenile stone crabs as habitat increased (i.e. weak habitat imitation). However, for adult stone crabs, density remained stable across treatments, demonstrating that habitat limitation presents a bottleneck in this species’ later life history. Oyster toadfish densities also did not change with increasing habitat availability (i.e. habitat limitation), but densities of other cryptic fishes decreased as habitat availability increased (i.e. weak limitation). Feeding and abundance data suggested that some mobile fishes experience habitat limitation, or, potentially in one case, strong limitation across our habitat manipulations. 5. These findings of significant, community-level habitat limitation provide insight into how global declines in structurally complex estuarine habitats may have reduced the fishery production of coastal ecosystems.

1. 量化移动消费者对栖息地可获得性变化的响应，是明确种群水平生产力受栖息地限制的程度，而非受其他潜在非密度制约因素调控的关键依据。
2. 在景观尺度下，可通过监测栖息地可获得性变化时的种群密度与觅食行为变化，探究该科学问题。随栖息地可获得性提升，种群密度可能出现三种响应模式：(1) 下降（单位面积生产力降低，属于弱栖息地限制）；(2) 保持稳定（单位面积生产力无变化，属于栖息地限制）；(3) 上升（单位面积生产力提升，属于强栖息地限制）。
3. 本研究开展了为期五个月的原位实验，探究移动性河口消费者对栖息地可获得性变化的响应，通过对比邻接或不邻接周边人工鱼礁、附近自然鱼礁的人工鱼礁上的种群密度与摄食率，完成实验测试。
4. 本研究通过构建或利用自然鱼礁操控栖息地可获得性，记录到随栖息地面积提升，幼年石蟹的种群密度出现三倍下降（即弱栖息地限制）。但成年石蟹的种群密度在各实验处理组间保持稳定，表明栖息地限制是该物种后期生活史中的关键瓶颈。蛎蟾鱼的种群密度也未随栖息地可获得性提升而发生变化（即属于栖息地限制），但其他隐蔽性鱼类的种群密度随栖息地可获得性提升而下降（即弱限制）。摄食与种群丰度数据显示，部分移动鱼类在本次栖息地操控实验中表现出栖息地限制，其中某一类群甚至可能存在强栖息地限制。
5. 这些群落水平的显著栖息地限制研究结果，有助于理解全球结构复杂的河口生境衰退如何降低了沿海生态系统的渔业生产力。