Abstract:

Urban green areas are important habitats for birds in rapidly urbanized areas. The composition of woody plant species has a significant influence on the structure of bird communities in urban green areas. Therefore, to enhance the function of public green areas as wild bird habitats, we studied how woody plants influenced the composition of the bird community in Binjiang Forest Park, a typical urban green area in Shanghai city. A total of 5,368 individual birds belonging to 64 species from 25 families and 10 orders were recorded during line transect and point-count surveys conducted between 2009 and 2010. Data on bird abundance showed significant differences among months, with the two highest abundances recorded in April and November. A plot of the data on bird species richness against time (months) showed a curve with two peaks, with the highest abundance recorded in April and December. The values of the Simpson index showed significant variation in bird diversity over the year, with the highest value recorded in October and the lowest in August. With square-plot (400 m²) sampling analysis, a total of 77 woody plant species in the park was identified. Only 14 of these species were recorded in at least five plots (nine trees and five shrubs). These species were considered common woody species. The fruiting seasons of 12 of these species occurred during periods between September and the following February. The principal outbreaks of insects with significance to forestry occurred from May to November. A principal component analysis was used to group all birds observed on the 14 woody plant species into 8 guilds according to their diets, foraging behaviors, and distributions in various vegetation layers. A Spearman correlation analysis indicated that the autumn-winter fruiting season was significantly positively correlated with 5 bird guilds, including vegetarians, omnivores, raptors, and insectivores. The abundant food supply coincided with the highest bird abundance and richness in autumn and winter. An analysis of the importance of each common woody plant species for the bird community was also performed based on the evaluation of the relative richness, relative abundance, and relative number of bird guilds. The results showed that during autumn and winter, fruiting plants provided rich food resources for terrestrial migratory birds; trees such as Populus lasiocarpa, Pterocarya stenoptera, and Cinnamomum camphora had a greater importance than shrubs. The relatively lower importance of the common shrub species to birds implies that the shrub community of the park needs to be reviewed. Comments and recommendations are provided based on our research results.

Key words: urbanization, urban green area, Shanghai, guild of birds, vegetation community, woody plant species