Targeted reforestation could reverse declines in connectivity for understory birds in a tropical habitat corridor
Targeted reforestation could reverse declines in connectivity for understory birds in a tropical habitat corridor
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有针对性的重新造林可以扭转热带栖息地走廊林下鸟类连通性的下降
DOI：
10.1890/14-2188
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发表时间：
2016-07-01
影响因子：
5
通讯作者：
Chazdon, Robin L.
中科院分区：
文献类型：
--
作者：
Fagan, Matthew E.;DeFries, Ruth S.;Chazdon, Robin L.
重建因栖息地清理而隔离的保护区之间的连通性是潮湿热带地区的一个关键保护目标。在哥斯达黎加东北部，环境服务付费（PES）和政府禁止砍伐森林为圣胡安-拉塞尔瓦生物走廊（SJLSBC）的森林保护和重新造林提供了补贴，导致成熟森林损失减少和人工林面积扩大。我们使用实地研究和图表模型来评估过去 25 年中保护工作如何改变四种食虫林下鸟类的功能连通性。实地回放研究评估了重新造林栖息地质量如何影响 Myrmeciza exsul、Henicorhina leucosticta、Thamnophilus atrinucha 和 Glyphorynchus spirurus 离开森林栖息地进行领地防御的意愿。观察到的行进距离在林下茎密度高的非本地和本地人工林中最大，无论地上层成分如何。相比之下，对于四种鸟类中的三种来说，茎密度低的人工林的旅行响应与开放牧场相当。我们根据人工林、画廊森林和牧场中不同的可能旅行距离，使用图形模型对每个物种的景观连通性进行了建模。从 1986 年到 2011 年，SJLSBC 景观（5825 km(2)）中所有物种的连通性下降了 14% 至 21%，尽管森林面积净损失仅为 4.9%，且人工林迅速扩张，占景观面积的 2% 以上。景观中的种植园布局限制了其潜在的连通性，因为它们要么远离森林覆盖，要么位于已经连续的森林区域内。我们绘制了当前的连接瓶颈并确定了未来重新造林的优先领域。我们估计，优先地区的重新造林可以将连通性提高 2%，而森林覆盖率仅增加 1%，考虑到重新造林的面积较小，这是一个令人印象深刻的收益。结果表明，SJLSBC 研究区域内的 PES 空间目标将保护现有森林连通性并增强重新造林的连通性效益。
Re-establishing connectivity between protected areas isolated by habitat clearing is a key conservation goal in the humid tropics. In northeastern Costa Rica, payments for environmental services (PES) and a government ban on deforestation have subsidized forest protection and reforestation in the San Juan-La Selva Biological Corridor (SJLSBC), resulting in a decline in mature forest loss and the expansion of tree plantations. We use field studies and graph models to assess how conservation efforts have altered functional connectivity over the last 25 years for four species of insectivorous understory birds. Field playback studies assessed how reforestation habitat quality affected the willingness of Myrmeciza exsul, Henicorhina leucosticta, Thamnophilus atrinucha, and Glyphorynchus spirurus to travel outside forest habitat for territorial defense. Observed travel distances were greatest in non-native and native tree plantations with high understory stem density, regardless of overstory composition. In contrast, tree plantations with low stem density had travel responses comparable to open pasture for three of the four bird species. We modeled landscape connectivity for each species using graph models based on varying possible travel distances in tree plantations, gallery forests, and pastures. From 1986 to 2011, connectivity for all species declined in the SJLSBC landscape (5825 km(2)) by 14% to 21% despite only a 4.9% net loss in forest area and the rapid expansion of tree plantations over 2% of the landscape. Plantation placement in the landscape limited their potential facilitation of connectivity because they were located either far from forest cover or within already contiguous forest areas. We mapped current connectivity bottlenecks and identified priority areas for future reforestation. We estimate that reforestation of priority areas could improve connectivity by 2% with only a 1% gain in forest cover, an impressive gain given the small area reforested. Results indicate key locations where spatial targeting of PES within the SJLSBC study region would protect existing forest connectivity and enhance the connectivity benefits of reforestation.