Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27412.
Salmon and Freshwater Fisheries Research Institute, Hokkaido Research Organization, Eniwa, Hokkaido 061-1433, Japan.
Proc Natl Acad Sci U S A. 2023 Feb 14;120(7):e2218044120. doi: 10.1073/pnas.2218044120. Epub 2023 Feb 7.
The massive release of captive-bred native species ("intentional release") is a pervasive method to enhance wild populations of commercial and recreational species. However, such external inputs may disrupt the sensitive species interactions that allow competing species to coexist, potentially compromising long-term community stability. Here, we use theory and long-term data of stream fish communities to show that intentional release destabilizes community dynamics with limited demographic benefit to the enhanced species. Our theory predicted that intentional release intensifies interspecific competition, facilitating the competitive exclusion of unenhanced species that otherwise stably coexist. In parallel, the excessive input of captive-bred individuals suppressed the natural recruitment of the enhanced species via intensified within-species competition. Consequently, the ecological community with the intentional release is predicted to show reduced community density with unstable temporal dynamics. Consistent with this prediction, stream fish communities showed greater temporal fluctuations and fewer taxonomic richness in rivers with the intensive release of hatchery salmon-a major fishery resource worldwide. Our findings alarm that the current overreliance on intentional release may accelerate global biodiversity loss with undesired consequences for the provisioning of ecosystem services.
大规模释放圈养的本地物种（“有意释放”）是一种普遍的方法，可以增加商业和娱乐物种的野生种群。然而，这种外部投入可能会破坏允许竞争物种共存的敏感物种相互作用，从而有可能危及长期的社区稳定性。在这里，我们使用溪流鱼类群落的理论和长期数据表明，有意释放会破坏群落动态，对增强物种的人口增长没有带来明显的好处。我们的理论预测，有意释放会加剧种间竞争，有利于原本稳定共存的非增强物种的竞争排斥。同时，圈养个体的过度输入通过加剧种内竞争，抑制了增强物种的自然繁殖。因此，有意释放的生态群落预计会表现出较低的群落密度和不稳定的时间动态。与这一预测一致的是，溪流鱼类群落显示出更大的时间波动和较少的分类丰富度，在有密集释放孵化鲑鱼的河流中，鲑鱼是全球重要的渔业资源。我们的研究结果表明，目前对有意释放的过度依赖可能会加速全球生物多样性的丧失，并对生态系统服务的提供产生不良后果。
