Department of Ecology, University of Debrecen, Debrecen, Hungary.
Department of Agroecology, Aarhus University, Flakkebjerg Research Centre, Slagelse, Denmark.
Sci Rep. 2018 Nov 19;8(1):16992. doi: 10.1038/s41598-018-35293-8.
Urbanization fragments, isolates or eliminates natural habitats, and changes the structure and composition of assemblages living in the remaining natural fragments. Knowing assembly rules is necessary to support and/or maintain biodiversity in urban habitats. We hypothesized that forest communities in rural sites are organized by environmental filtering, but this may be changed by urbanization, and in the suburban and urban forest fragments replaced by randomly organized assemblages, influenced by the colonization of species from the surrounding matrix. Evaluating simultaneously the functional and phylogenetic relationships of co-existing species, we showed that at the rural sites, co-existing ground beetle species were functionally and phylogenetically more similar than expected by chance, indicating that environmental filtering was the likely process structuring these communities. Contrary to this, in urban and suburban sites, the co-occurring species were functionally and phylogenetically not different from the null model, indicating randomly structured assemblages. According to our findings, changes in environmental and habitat characteristics accompanied by urbanization lead to assemblages of randomly colonized species from the surrounding matrix, threatening proper ecosystem functioning. To reassemble stochastically assembled species of urban and suburban fragments to structured, properly functioning communities, appropriate management strategies are needed which simultaneously consider recreational, economic and conservation criteria.
城市化会使自然栖息地破碎化、孤立化或消失，并改变生活在剩余自然栖息地中的生物组合的结构和组成。了解组合规则对于支持和/或维护城市栖息地的生物多样性是必要的。我们假设，农村地区的森林群落是由环境过滤组织的，但这可能会因城市化而改变，在郊区和城市森林斑块中，由周围基质中物种的定居取代，受随机组织的组合的影响。同时评估共存物种的功能和系统发育关系，我们表明，在农村地区，共存的地面甲虫物种在功能和系统发育上比随机预期更相似，这表明环境过滤是塑造这些群落的可能过程。与此相反，在城市和郊区地区，共存物种在功能和系统发育上与零模型没有区别，这表明随机结构的组合。根据我们的发现，城市化伴随的环境和栖息地特征的变化会导致来自周围基质的随机定居的物种聚集，从而威胁到适当的生态系统功能。为了将城市和郊区碎片中随机聚集的物种重新组合成结构合理、功能正常的群落，需要采取适当的管理策略，同时考虑娱乐、经济和保护标准。
