Department of Biological Science, Chicago State University, Chicago, IL, USA.
Negaunee Integrative Research Center, The Field Museum of Natural History, Chicago, IL, 60605, USA.
Sci Rep. 2021 Aug 9;11(1):16129. doi: 10.1038/s41598-021-95516-3.
The Atlantic Forest of eastern Paraguay has experienced extensive recent deforestation. Less than one-third of the region is forested, and the remaining forest largely consists of isolated remnants with potentially disrupted connectivity for forest fauna. We used a graph theory approach to identify those forest remnants that are important in maintaining landscape structural connectivity for mammals in this fragmented forest. We quantified structural connectivity for forest remnants over the period 2000-2019 at three levels: the entire network of Atlantic Forest remnants in eastern Paraguay; at 10 smaller, nested spatial scales (40-10,000 m) encompassing a range of potential mammalian dispersal abilities; and at the level of individual remnants. We used 10 graph theory metrics to assess aspects of network complexity, dispersal-route efficiency, and individual remnant importance in supporting structural connectivity. We identified forest remnants that serve as important structural connectivity roles as stepping stones, hubs, or articulation points and that should be prioritized for connectivity conservation. Structural connectivity was constrained for organisms incapable of travelling at least 9-12 km (farthest distances between nearest-neighboring forest remnants depending on whether smaller remnants were included or not) and was particularly limited for area-sensitive forest-specialist mammals. With the increased forest loss and fragmentation that is occurring, the connectivity of this system will likely be further compromised, but most of the remnants that we identified as playing important roles for structural connectivity were outside of the country's proposed "green corridor," indicating additional areas where conservation action can be directed.
巴西北部大西洋森林地区最近经历了大规模的森林砍伐。该地区只有不到三分之一的面积被森林覆盖，其余的森林主要由孤立的残余部分组成，这些残余部分的连通性可能受到破坏，不利于森林动物的生存。我们使用图论方法来确定在这个破碎化的森林中，哪些森林残余部分对于维持哺乳动物的景观结构连通性非常重要。我们在三个层次上量化了森林残余部分的结构连通性：整个巴西北部大西洋森林残余网络；在 10 个较小的嵌套空间尺度（40-10000 米）上，涵盖了一系列潜在的哺乳动物扩散能力；以及在单个残余部分的水平上。我们使用了 10 种图论指标来评估网络复杂性、扩散路径效率以及单个残余部分在支持结构连通性方面的重要性。我们确定了那些作为重要结构连通性作用的森林残余部分，如踏脚石、枢纽或连接点，这些残余部分应该优先考虑进行连通性保护。对于那些无法至少移动 9-12 公里（取决于是否包括较小的残余部分，这是最近的相邻森林残余部分之间的最远距离）的生物来说，结构连通性受到限制，而对于对面积敏感的森林特化哺乳动物来说，结构连通性受到的限制尤其严重。随着森林不断减少和破碎化，该系统的连通性可能会进一步受到损害，但我们确定的在结构连通性方面发挥重要作用的大多数残余部分都不在该国拟议的“绿色走廊”内，这表明还需要在其他地区采取保护行动。
