Structural characteristics and niches of dominant tree populations in Tetracentron sinense communities: implications for conservation

Abstract

Background: Tetracentron sinense Oliv., is an endangered, broad-leaved tree distributed in south-central China. Structural characteristics of the community and dominant tree population niches in T. sinense communities are currently unclear.Questions: (1) What is the status of T. sinense populations in the community? (2) What are the interspecies interactions between T. sinense populations and its associated species. Study sites and dates: T. sinense communities in Meigu Dafengding Nature Reserve in southwest China in 2014.Methods: Six sites of 400 m2 were studied for importance value, special diversity, niche breadth, and overlap of dominant tree populations. Results: There were 80 species, 67 genera, and 41 families of vascular plants. Sixty-one genera of seed plants in T. sinense communities were classified into 9 types. The North Temperate genus was the largest, accounting for 44.26 %. Species richness, species diversity, and evenness indexes were all low. There were 6 dominant tree populations in T. sinense communities, and the importance values and niche breadths of T. sinense populations were significantly higher than other species. Horizontal niche overlaps between T. sinense and Pterocarya stenoptera, Acer pictum subsp. mono , and Cercidiphyllum japonicum were high; the vertical niche overlaps between T. sinense and these species were all greater than 0.7.Conclusions: T. sinense communities have North Temperate character, and are immature and unstable communities, still in the early stage of succession. T. sinense is the edificator tree in the communities. A high similarity of habitat demand and strong interspecific competition for light exist between T. sinense and its associated trees.