Influencing Factors Of Spatial Structure In A Saltmarsh Passerine Bird Community In Jiangsu Dafeng Milu National Natural Reserve

A variety of factors affect the spatial distribution of individual birds and community spatial structure, most researches focused on the important effect of habitat preference but ignored the effect of individual interaction because that it is hard to get rid of the influence of environment. Spartina alterniflora has developed the single dominant community and the mixed communities composed by native plantin saltmarsh habitat at Dafeng Natural Reserve after its invasion. This unique habitat provide a valuable natural experimental field for exploring the influence of both individual interaction and habitat preference to the spatial distribution of bird community at the same time. Preliminary investigation showed that the numbers of birds and bird species declined while the passerine Locustella pryeri became the dominant bird species. To uncover factors that affect spatial structure of birds community of this saltmarsh, we monitored the territory of male birds during March to May in 2014. Eight vegetation parameters were measured by using quadrat method, and 36 relationships of 6 species were analysis with random allocation by computer simulation at multi-scale. The major results of present study are summarized as follows:1) Interaction between individuals and habitat preferences effect the spatial structure of the saltmarsh bird communities in Dafeng Milu National Nature Reserve. Through multi-scale analysis to habitat preferences and interaction between individuals are discussed respectively, in the local saltmarsh habitat, both on the spatial structure of birds community exist at the same time, the influence of and the influence of the habitat preferences will increase with the increase of scale.2) Since the invasion of Spartina alterniflora,salt marsh habitat heterogeneity resulting reduced, decided to distribution of birds in the Spartina alterniflora single communities or mixed native vegetation community is still the main factors that habitat preferences, Spartina alterniflora s between individual birds, dominated community interaction on the distribution of the spatial structure of its community is more significant.3) In local saltmarsh habitat, the habitat preferences for Locustella pryeri and Cisticola juncidis plays a positive effect, Paradoxornis webbianus and Paradoxornis heudei plays a negative impact. Interactions between individuals in Locustella pryeri, for Cisticola juncidis plays a negative impact.4) Locustella pryeri interactions between individuals within species is one of the most important reasons to adapt to salt marsh habitats Spartina alterniflora communities. And Locustella pryeri and Cisticola juncidis is a pair of few competing species in the salt marsh habitat, the interspecific interaction for saltmarsh birds community structure plays a very important role.5) Spartina alterniflora communities are still a large number of empty niche, so breeding birds in Spartina alterniflora single communities such as Locustella pryeri can maintain the greater habitat territory area than the reed, the other birds are also beginning to spread and adapt to Spartina alterniflora communities, such as Paradoxornis webbianus.This study provides a theoretical basis for exploring mechanisms of how birds colonization and spread in invasion vegetation, and shed light on our understands of how the birds adapt to rapid changing environment nowadays.