Effects of matrix composition and configuration on forest bird movements in a fragmented Afromontane biodiversity hot spot
Effects of matrix composition and configuration on forest bird movements in a fragmented Afromontane biodiversity hot spot
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DOI：
10.1111/j.1469-1795.2012.00562.x
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发表时间：
2012-12-01
影响因子：
3.4
通讯作者：
Matthysen, E.
中科院分区：
文献类型：
--
作者：
Aben, J.;Adriaensen, F.;Matthysen, E.
支离破碎的景观中依赖森林的物种的持续存在强烈依赖于斑块之间的充分分散，因此了解动物运动如何受到干预基质的影响非常重要。根据认为是否适合觅食或提供掩护，通过选择或避免土地覆盖来影响运动。因此，矩阵的组成和配置很可能是估计斑块之间的连接性时要考虑的重要因素。为了解决这个问题，我们进行了易位实验，以了解森林鸟类如何在分散的非洲山区生物多样性热点（肯尼亚泰塔山）的细粒度矩阵中使用不同的土地覆盖类型。我们的研究结果表明，对于森林专家卡巴尼斯绿蝶 (Cabanis's greenbul) Phyllastrephus cabanisi 和森林通才白星知更鸟 Pogonocichla stellata 而言，土地覆盖类型的使用与其可用性不成比例。然而，这种效果受到矩阵配置的影响；在斑块矩阵中，与更均匀的矩阵相比，土地覆盖选择更加明显，特别是对于森林专家而言。在移动步骤的规模上，风险规避似乎是这两个物种的路线决策中的一个重要因素。观察到的台阶平均包含较低比例的开放土地覆盖，并且与建成区相交的频率低于预期。 P.?stellata 不区分不同的土地覆盖类型，而 P.?cabanisi 更喜欢含有更多原生森林的台阶。观察到的森林依赖程度与基质渗透性之间的负相关关系意味着，对于泰塔鸟类群落的成员来说，它们更加依赖完整的森林栖息地（即极度濒危的泰塔画眉Turdus helleri），当前基质的渗透性可能更低。因此，为了改善连通性而进行的基质恢复可能是这些支离破碎的非洲山地景观中依赖森林的物种长期生存的重要手段。
Persistence of forest-dependent species in fragmented landscapes strongly relies on sufficient dispersal between patches, making it important to understand how animal movements are affected by the intervening matrix. Movements can be influenced through selection or avoidance of land cover based on their perceived suitability for foraging or providing cover. The composition and configuration of the matrix will, therefore, most likely be an important factor to consider when estimating connectivity between patches. To address this, we performed translocation experiments to understand how forest birds used different land cover types in a fine-grained matrix of a fragmented Afromontane biodiversity hot spot (Taita Hills, Kenya). Our results revealed that use of land cover types for both the forest specialist Cabanis's greenbul Phyllastrephus cabanisi and for the forest generalist white-starred robin Pogonocichla stellata was disproportional to their availability. However, this effect was influenced by matrix configuration; in patchy matrices, land cover selection was more pronounced compared with more uniform matrices, especially for the forest specialist. At the scale of movement steps, risk avoidance seemed to be a strong factor in the route decisions for both species. Observed steps contained on average lower proportions of open land cover and did less frequently intersect built-up areas than expected. P.?stellata did not differentiate between the alternative land cover types, whereas P.?cabanisi preferred steps that contained more indigenous forest. The observed negative relationship between degree of forest dependency and matrix permeability implies that for members of the Taita bird community, which are even more dependent on intact forest habitat (i.e. the critically endangered Taita thrush Turdus helleri), current permeability of the matrix may be even lower. Matrix restoration to improve connectivity may, therefore, be a crucial instrument for the long-term survival of forest-dependent species in these fragmented Afromontane landscapes.