Urban orchards provide a suitable habitat for epiphytic bryophytes

Abstract

Current rapid urbanization has significantly increased the areas occupied by agroforests, such as orchards, within urban boundaries. However, studies on the potential of agroforests to provide suitable habitats for urban biodiversity are scarce, especially for epiphytes, which are extremely sensitive to abrupt environmental changes. The objective of this study is to assess the potential of orchards to provide habitats for epiphytes in urban areas. For this purpose, we surveyed epiphytic bryophytes on the trunks of trees in urban orchards (longan and lychee) and different-aged secondary forests in Shenzhen, China. Young secondary forests had the same age as that of orchards and older secondary forests were twice as old. The diversity, species composition, and distribution of epiphytic bryophytes among different forests were compared. The species richness, coverage, Shannon index, evenness, and number of unique species were used to evaluate the diversity of epiphytic bryophytes. Non-metric multidimensional scaling and analysis of similarity methods were applied to examine the differences in species composition among orchards and secondary forest stands. The species richness and coverage of bryophytes, depending on the trunk height and orientation, were also compared. The results showed that (i) the richness of bryophyte species was higher in the urban orchards than in the secondary forests; although the coverage was also higher in the urban orchards than in the young secondary forests, it was lower than that in an older secondary forest; (ii) significant differences in the species composition were revealed between the urban orchards and the secondary forests; (iii) bryophytes preferred the north side and the middle and lower parts of the tree trunk in both the urban orchards and secondary forests. This study is the first to reveal that orchards have a higher potential than secondary forests to provide habitats for epiphytic bryophytes in urban environments. Therefore, this study provides valuable information for government agencies and urban forest managers to protect epiphyte habitats and improve the conservation of urban biodiversity.