Impact of invasion of pine wood nematode on the niche of main populations in Masson pine community

The niche characteristics of 13 main tree populations among Masson pine community at different damage phases were analyzed by a quantitative method.The niche breadth,niche proportional similarity and niche overlap of the main populations in Masson pine community in different damage phases were measured by taking following community composition types:1) Pinus massoniana + Loropetalum chinense +Quercus fabri,2) P.thunbergii + P.massoniana + Ilex purpurea+ Eurya japonica,3) P.massoniana + I.purpurea+Gardenia jasminoides+Q.glandulifera var. brevipetiolata,4) P.massoniana +Phyllostachys nidularia + L.chinense,5) Schima superba +P.massoniana + Castanopsis sclerophylla + Q.glandulifera var.brevipetiolata,6) Q.variabilis + I.purpurea +Callicarpa formosana,and the integrated index of resource gradient(10(-)70) established as one dimension resource stated with 6 investigating plots.Also,the ecological significance of the results were demonstrated.It showed that with the invasion of Bursaphelenchus xylophilus and the following disturbing measures taken by humans of cutting down the infected plants,the succession Masson pine forests was turning to two directions-broad leaved forests and Mixed forests of Masson pine & broadleaf tree.