Lynker, under contract to Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA, USA.
Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA, USA.
J Anim Ecol. 2021 Nov;90(11):2692-2703. doi: 10.1111/1365-2656.13575. Epub 2021 Oct 6.
Environmental forces can create spatially synchronous dynamics among nearby populations. However, increased climate variability, driven by anthropogenic climate change, will likely enhance synchrony among spatially disparate populations. Population synchrony may lead to greater fluctuations in abundance, but the consequences of population synchrony across multiple scales of biological organization, including impacts to putative competitors, dependent predators or human communities, are rarely considered in this context. Chinook salmon Oncorhynchus tshawytscha stocks distribute across the Northeast Pacific, creating spatially variable portfolios that support large ocean fisheries and marine mammal predators, such as killer whales Orcinus orca. We rely on a multi-population model that simulates Chinook salmon ocean distribution and abundance to understand spatial portfolios, or variability in abundance within and among ocean distribution regions, of Chinook salmon stocks across 17 ocean regions from Southeast Alaska to California. We found the expected positive correlation between the number of stocks in an ocean region and spatial portfolio strength; however, increased demographic synchrony eroded Chinook salmon spatial portfolios in the ocean. Moreover, we observed decreased resource availability within ocean fishery management jurisdictions but not within killer whale summer habitat. We found a strong portfolio effect across both Southern Resident and Northern Resident killer whale habitats that was relatively unaffected by increased demographic synchrony, likely a result of the large spatial area included in these habitats. However, within the areas of smaller fishing management jurisdictions we found a weakening of Chinook salmon portfolios and increased but inconsistent likelihood of low abundance years as demographic synchrony increased. We suggest that management and conservation actions that reduce spatial synchrony can enhance short-term ecosystem resilience by promoting the stabilizing effect multiple stocks have on aggregate Chinook salmon populations and overall resource availability.
环境因素可以在附近的种群之间产生空间同步的动态。然而，由于人为气候变化导致的气候变异性增加，可能会增强空间上离散的种群之间的同步性。种群同步性可能导致丰度更大的波动，但在这种情况下，很少考虑到种群同步性对多个生物组织尺度的影响，包括对假定的竞争者、依赖的捕食者或人类社区的影响。奇努克三文鱼 Oncorhynchus tshawytscha 种群分布在东北太平洋，形成了空间上可变的组合，支持大型海洋渔业和海洋哺乳动物捕食者，如虎鲸 Orcinus orca。我们依靠一个多种群模型来模拟奇努克三文鱼的海洋分布和丰度，以了解奇努克三文鱼种群在从东南阿拉斯加到加利福尼亚的 17 个海洋区域的海洋分布区域内和之间的丰度的空间组合，或丰度的变异性。我们发现海洋区域内的种群数量与空间组合强度之间存在预期的正相关关系；然而，人口统计同步性的增加侵蚀了奇努克三文鱼在海洋中的空间组合。此外，我们观察到海洋渔业管理管辖区内的资源可用性减少，但在虎鲸夏季栖息地内没有减少。我们在南部居民和北部居民虎鲸栖息地都发现了强烈的组合效应，这种效应相对不受人口统计同步性的影响，这可能是由于这些栖息地包含的空间面积较大。然而，在较小的渔业管理管辖区内，我们发现奇努克三文鱼的投资组合正在减弱，并且随着人口统计同步性的增加，低丰度年份的可能性增加，但并不一致。我们认为，减少空间同步的管理和保护措施可以通过促进多种股票对奇努克三文鱼种群和整体资源可用性的稳定作用来增强短期生态系统的弹性。
