Dittbrenner Benjamin J, Pollock Michael M, Schilling Jason W, Olden Julian D, Lawler Joshua J, Torgersen Christian E
School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, United States of America.
National Oceanic and Atmospheric Administration - Northwest Fisheries Science Center, Seattle, Washington, United States of America.
PLoS One. 2018 Feb 28;13(2):e0192538. doi: 10.1371/journal.pone.0192538. eCollection 2018.
Through their dam-building activities and subsequent water storage, beaver have the potential to restore riparian ecosystems and offset some of the predicted effects of climate change by modulating streamflow. Thus, it is not surprising that reintroducing beaver to watersheds from which they have been extirpated is an often-used restoration and climate-adaptation strategy. Identifying sites for reintroduction, however, requires detailed information about habitat factors-information that is not often available at broad spatial scales. Here we explore the potential for beaver relocation throughout the Snohomish River Basin in Washington, USA with a model that identifies some of the basic building blocks of beaver habitat suitability and does so by relying solely on remotely sensed data. More specifically, we developed a generalized intrinsic potential model that draws on remotely sensed measures of stream gradient, stream width, and valley width to identify where beaver could become established if suitable vegetation were to be present. Thus, the model serves as a preliminary screening tool that can be applied over relatively large extents. We applied the model to 5,019 stream km and assessed the ability of the model to correctly predict beaver habitat by surveying for beavers in 352 stream reaches. To further assess the potential for relocation, we assessed land ownership, use, and land cover in the landscape surrounding stream reaches with varying levels of intrinsic potential. Model results showed that 33% of streams had moderate or high intrinsic potential for beaver habitat. We found that no site that was classified as having low intrinsic potential had any sign of beavers and that beaver were absent from nearly three quarters of potentially suitable sites, indicating that there are factors preventing the local population from occupying these areas. Of the riparian areas around streams with high intrinsic potential for beaver, 38% are on public lands and 17% are on large tracts of privately-owned timber land. Thus, although there are a large number of areas that could be suitable for relocation and restoration using beavers, current land use patterns may substantially limit feasibility in these areas.
通过筑坝活动及随后的蓄水，海狸有潜力恢复河岸生态系统，并通过调节水流来抵消一些气候变化的预测影响。因此，将海狸重新引入已灭绝的流域是一种常用的恢复和气候适应策略，这并不奇怪。然而，确定重新引入的地点需要有关栖息地因素的详细信息，而这种信息在大空间尺度上并不常见。在这里，我们利用一个模型探索在美国华盛顿州斯诺霍米什河流域重新安置海狸的潜力，该模型仅依靠遥感数据来识别海狸栖息地适宜性的一些基本要素。更具体地说，我们开发了一个广义内在潜力模型，该模型利用溪流坡度、溪流宽度和山谷宽度的遥感测量数据来确定如果有合适的植被，海狸可能在哪里定居。因此，该模型可作为一种初步筛选工具，可应用于相对较大的范围。我们将该模型应用于5019公里的溪流，并通过对352个溪流河段进行海狸调查，评估了该模型正确预测海狸栖息地情况的能力。为了进一步评估重新安置的潜力，我们评估了不同内在潜力水平的溪流河段周围景观中的土地所有权、用途和土地覆盖情况。模型结果表明，33%的溪流具有中等或高的海狸栖息地内在潜力。我们发现，被归类为内在潜力低的地点没有任何海狸的迹象，并且近四分之三的潜在适宜地点没有海狸，这表明存在一些因素阻止当地海狸种群占据这些区域。在海狸内在潜力高的溪流周围的河岸地区中，38%位于公共土地上，17%位于大片私人拥有的林地。因此，尽管有大量地区适合利用海狸进行重新安置和恢复，但目前的土地利用模式可能会在很大程度上限制这些地区的可行性。
