دانلود رایگان مقاله انگلیسی عوامل تعیین کننده غنای گونه ها در داخل و خارج از گروه های طبقه بندی در فضای سبز شهری - اشپرینگر 2017

Abstract

Urban green spaces provide habitat for numerous plant and animal species. However, currently we have little knowledge on which determinants drive the species richness within and across taxonomic groups. In this paper we investigate the determinants of total, native, and endangered species richness for vascular plants, birds, and mammals within and across taxonomic groups. We examined a stratified random sample of 32 urban green spaces in Hannover, Germany. Species inventories for plants and birds were generated on the basis of line transect surveys. Mammals were surveyed by means of point counts using camera traps. Using a principal component analysis and multiple regression models, we tested 10 explanatory variables for species-area effects, distance effects, and the effects of habitat structure of green spaces on species richness. When analyzing single explanatory variables, we determined that the species richness of all groups was significantly positively correlated to patch area, number of habitat types, and a short distance to the nearest green space. Testing combined effects of variables showed that patch area in combination with habitat heterogeneity was most important for plants (total, native, and endangered), birds (total and native), and overall species richness. This emphasizes the importance of the species-area effect and the effects of habitat structure on species richness in urban green spaces. We conclude that, in the context of urban planning, it is important to conserve large green spaces that include a high diversity of habitats to maintain high species richness.

Conclusion

We conclude that, in the context of urban planning, it is important to conserve large green spaces that include a high number and high diversity of habitats. Several other studies have identified a minimum threshold size of 10 ha to secure high species richness in urban green spaces (cf. Nielsen et al. 2014). For total plant species richness, a short distance to the urban edge and a compact shape of green spaces could be beneficial. According to our results of the single explanatory variable analysis, a short distance to the next urban green space would also benefit the species richness of all investigated taxonomic groups (cf. Bräuniger et al. 2010). Additionally, a high connectivity of green spaces positively affects native plant and total mammal species richness. Our results provide strong evidence that green space area, as well as habitat heterogeneity, and especially the combination of these two variables, are important determinants of species richness within and across vascular plant, bird, and mammal species richness.