Department of Ecology, University of Debrecen, Debrecen, Hungary.
Department of Agroecology, Flakkebjerg Research Centre, Aarhus University, Slagelse, Denmark.
Insect Sci. 2019 Feb;26(1):154-163. doi: 10.1111/1744-7917.12504. Epub 2017 Aug 30.
In a fragmented landscape, transitional zones between neighboring habitats are common, and our understanding of community organizational forces across such habitats is important. Edge studies are numerous, but the majority of them utilize information on species richness and abundance. Abundance and taxonomic diversity, however, provide little information on the functioning and phylogeny of the co-existing species. Combining the evaluation of their functional and phylogenetic relationships, we aimed to assess whether ground beetle assemblages are deterministically or stochastically structured along grassland-forest gradients. Our results showed different community assembly rules on opposite sides of the forest edge. In the grassland, co-occurring species were functionally and phylogenetically not different from the random null model, indicating a random assembly process. Contrary to this, at the forest edge and the interior, co-occurring species showed functional and phylogenetic clustering, thus environmental filtering was the likely process structuring carabid assemblages. Community assembly in the grassland was considerably affected by asymmetrical species flows (spillover) across the forest edge: more forest species penetrated into the grassland than open-habitat and generalist species entered into the forest. This asymmetrical species flow underlines the importance of the filter function of forest edges. As unfavorable, human-induced changes to the structure, composition and characteristics of forest edges may alter their filter function, edges have to be specifically considered during conservation management.
在破碎的景观中，相邻栖息地之间的过渡带很常见，因此我们理解跨栖息地的群落组织力量非常重要。边缘研究很多，但大多数研究都利用了物种丰富度和丰度的信息。然而，丰度和分类多样性几乎不能提供共存物种功能和系统发育的信息。通过评估它们的功能和系统发育关系，我们旨在评估是否沿着草地-森林梯度，地面甲虫组合是确定性的还是随机的结构。我们的研究结果表明，森林边缘两侧的群落组装规则不同。在草原上，共存物种在功能和系统发育上与随机零模型没有区别，表明存在随机组装过程。与此相反，在森林边缘和内部，共存物种表现出功能和系统发育聚类，因此环境过滤可能是塑造鞘翅目昆虫组合的过程。草地中的群落组装受到森林边缘两侧不对称物种流动（扩散）的显著影响：进入草原的森林物种比开阔栖息地和一般物种多。这种不对称的物种流动强调了森林边缘过滤功能的重要性。由于人为对森林边缘的结构、组成和特征进行不利的改变可能会改变它们的过滤功能，因此在保护管理中必须特别考虑边缘。
