Häkkilä Matti, Abrego Nerea, Ovaskainen Otso, Mönkkönen Mikko
Department of Biological and Environmental Sciences University of Jyväskylä Jyväskylä Finland.
Department of Agricultural Sciences University of Helsinki Helsinki Finland.
Ecol Evol. 2018 Mar 25;8(8):4019-4030. doi: 10.1002/ece3.3923. eCollection 2018 Apr.
Protected areas are meant to preserve native local communities within their boundaries, but they are not independent from their surroundings. Impoverished habitat quality in the matrix might influence the species composition within the protected areas through biotic homogenization. The aim of this study was to determine the impacts of matrix quality on species richness and trait composition of bird communities from the Finnish reserve area network and whether the communities are being subject of biotic homogenization due to the lowered quality of the landscape matrix. We used joint species distribution modeling to study how characteristics of the Finnish forest reserves and the quality of their surrounding matrix alter species and trait compositions of forest birds. The proportion of old forest within the reserves was the main factor in explaining the bird community composition, and the bird communities within the reserves did not strongly depend on the quality of the matrix. Yet, in line with the homogenization theory, the beta-diversity within reserves embedded in low-quality matrix was lower than that in high-quality matrix, and the average abundance of regionally abundant species was higher. Influence of habitat quality on bird community composition was largely explained by the species' functional traits. Most importantly, the community specialization index was low, and average body size was high in areas with low proportion of old forest. We conclude that for conserving local bird communities in northern Finnish protected forests, it is currently more important to improve or maintain habitat quality within the reserves than in the surrounding matrix. Nevertheless, we found signals of bird community homogenization, and thus, activities that decrease the quality of the matrix are a threat for bird communities.
保护区旨在保护其范围内的本地社区，但它们并非独立于周围环境。基质中栖息地质量的下降可能通过生物同质化影响保护区内的物种组成。本研究的目的是确定基质质量对芬兰保护区网络中鸟类群落物种丰富度和性状组成的影响，以及由于景观基质质量下降，这些群落是否正在经历生物同质化。我们使用联合物种分布模型来研究芬兰森林保护区的特征及其周围基质的质量如何改变森林鸟类的物种和性状组成。保护区内老龄林的比例是解释鸟类群落组成的主要因素，保护区内的鸟类群落并不强烈依赖于基质的质量。然而，与同质化理论一致，嵌入低质量基质中的保护区内的β多样性低于高质量基质中的β多样性，区域丰富物种的平均丰度更高。栖息地质量对鸟类群落组成的影响在很大程度上由物种的功能性状来解释。最重要的是，老龄林比例低的地区群落专业化指数低，平均体型大。我们得出结论，对于保护芬兰北部受保护森林中的本地鸟类群落，目前改善或维持保护区内的栖息地质量比改善或维持周围基质中的栖息地质量更为重要。然而，我们发现了鸟类群落同质化的迹象，因此，降低基质质量的活动对鸟类群落构成威胁。
