Objective  As a main component of coastal bird habitat, coastal green space is a strategic area for bird diversity conservation in China. Scientific habitat survey and assessment is not only the basis for bird diversity conservation in coastal green spaces, but also the premise for planning and design of ecological landscapes in urban coastal zones. This research is conducted in the context of urban biodiversity conservation and coastal zone construction, which aims to evaluate the bird diversity and habitat quality in the coastal green space in Dongdao Tsui, Yantai City by constructing a habitat suitability evaluation model, which may provide a reference for urban bird habitat construction and coastal ecological landscape planning and design.

Methods  This research takes the coastal green space in Dongdao Tsui, Yantai City, Shandong Province as the research area. Through field investigation, the research analyzes the characteristics of bird diversity. Meanwhile, the research adopts the correlation analysis and redundancy analysis (RDA) methods to explore the influence of 19 environmental factors on bird diversity at the micro-habitat scale, which respectively represent the status of food source, shelter and interference. In addition, considering that the habitat suitability index (HSI) is most commonly used in habitat quality evaluation, the research combines the HSI method and the analytic hierarchy process (AHP) method to build an evaluation model for bird habitat suitability in the coastal green space in Dongdao Tsui.

Results  The research finds that there are a total of 61 species of birds are recorded in Dongdao Tsui, mostly classified under Passerines and Charadriformes. The research further analyzes the distribution characteristics of such birds and relevant environmental influencing factors, which may be summarized as follows. 1) The dense deciduous forest with a large area and continuous distribution has the highest bird diversity, while farmlands and impervious surfaces have fewer bird species. 2) There are mainly 8 environmental factors influencing the distribution of bird diversity, including the coverage of trees, shrubs and herbs, etc. Specifically, the average height and the richness index of trees are significantly correlated with at least one index of bird diversity under different coastline distance gradients, and most of the significant influencing factors are related to tree structure. Compared with trees, the influence of herbs or shrubs on bird diversity is less significant. 3) The main factors influencing bird diversity are dissimilar at different distances from the coastline. As shown by the results of RDA, the average height of trees has the most significant influence on bird diversity in the offshore area, while the influence of plant factors on bird diversity is not significant in the land area 82 – 135 m away from the coastline. In the land area more than 135 m away from the coastline, the richness index of trees has the most significant influence on bird diversity. Based on the above results, the research builds a habitat suitability evaluation model to evaluate bird habitat quality in Dongdao Tsui, and the evaluation results show that the habitat suitability of birds is lower in the offshore area and higher in the land area further away from the coastline, and less than half (45.71%) of the total area is evaluated as moderately suitable or above.

Conclusion  This research underlines that forests composed of deciduous trees can greatly support the diversity of birds in coastal green spaces as they can provide birds with abundant food and solid shelter against the strong breeze from the sea, which means that the conservation of forest vegetation is very important for constructing bird habitat in coastal green spaces. In addition, farmlands and grasslands, although not having the highest bird diversity, can still provide necessary habitat space for some special bird species, which can be improved by providing more abundant edible plants and small ponds. Although the tidal flat on the coastline fails to be fully explored in this research, considering the ecological sensitivity thereof, the research still suggests minimizing the intervention of and taking strict conservation measures for tidal flat. Furthermore, the habitat suitability evaluation model can effectively simulate the quality distribution of bird habitats, and is expected to be of practical guiding significance for the planning and design of the coastal green space in Dongdao Tsui. However, the research is limited at the micro-habitat scale and mainly focuses on the influence of plant community factors on bird diversity, without further revealing the influence of environmental factors of coastal green space on bird diversity at any other spatiotemporal scale. Additionally, other environmental factors such as climate and water and predation and competition between species should also be considered. In view of this, it is suggested that future researches investigate and analyze bird habitats in coastal green spaces at other spatiotemporal scales, and further explore the environmental factors influencing bird diversity and the distribution of typical bird guilds, which will be conducive to the building of a more comprehensive evaluation system for habitat suitability in coastal green spaces and the planning and design of ecological landscape in urban coastal zones.