Community Structure And Spatial Correlation Of A Taxus Cuspidata-Pinus Koraiensis Forest

Taxus cuspidata is a survivor tertiary species and the national level endangered plants. The distribution of Taxus cuspidata population and the association between Taxus cuspidata and other major tree species were studied to explore the mechanism of species diversity preservation and community structure. Following the field protocol of 50 hm2 plot in Panama (Barro Colorado Island, BCI), a 25 hm2 plot was established in the growing season of 2014 in Muling National Nature Reserve of Heilongjiang Province. All free-standing plant species with DBH (diameter at breast height)≥ 1 cm were mapped, tagged, and identified to species. In the 2014 census, we documented 57 woody species with 63,877 individuals, belonging to 38 genera and 22 families. The DBH distribution of all individuals showed a reversed "J" type, indicating successful community regeneration. The DBH pattern of the nine dominant species can be classified into three categories: approximate normal (Taxus cuspidata), reversed "J" (Pinus koraiensis, Tilia amurensis, Acer mono, Acer barbinerve, Acer tegmentosum, Betula costata, Abies nephrolepis), and "L" distribution (Corylus mandshurica). Significant aggregation patterns were found in Taxus cuspidate (diameter classes of Ⅲ), Pinus koraiensis (diameter classes of Ⅰ and Ⅱ), Tilia amurensis (diameter classes of Ⅰ, Ⅱ and Ⅲ), Acer mono (diameter classes of Ⅰ, Ⅱ and Ⅲ), Abies nephrolepis (diameter classes of I and Ⅱ), and Acer tegmentosum (diameter classes of Ⅲ). Significant interspecific spatial associations were detected. Taxus cuspidata was positively correlated with four species (Acer mono, Pinus koraiensis, Abies nephrolepis and Tilia amurensis), but negatively correlated with the other four species (Acer tegmentosum, Corylus mandshurica, Betula costata and Acer barbinerve) at some scales. Taxus cuspidata forest has the higher species richness. Sapling regeneration of most of the species was fairly good, and sapling regeneration of Taxus cuspidata was poorest. Spatial distribution of species shows different habitat preference, and is significantly affected by habitat. Acer mono, Pinus koraiensis, Abies nephrolepis and Tilia amurensis are the optimal accompanying tree species for Taxus cuspidata. Acer tegmentosum, Corylus mandshurica, Betula costata, Acer barbinerve and Taxus cuspidata form niche separate.