广东南岭20 hm² 样地华南五针松空间分布与生境特征研究.

Understanding the ecological processes that affect species distribution patterns is fundamental to the conservation and restoration of rare and endangered species. Pinus kwangtungensis is an endemic and Class-II protected plant in China. However, environmental change and human disturbance result in habitat damage and population decline. In order to understand current situation of its population, spatial distribution pattern and habitat characteristics, and to guide the conservation and restoration of this species, we established a 20 hm² forest dynamics plot in the Nanling National Nature Reserve, Guangdong Province. All woody plants with diameter at breast height ≥1 cm were monitored, and multiple environmental factors, including soil and topography, were measured. We used a size-class analysis to predict population trends, the spatial point pattern analysis(L function)to reveal spatial distribution of individuals, and established a Zero-Inflated Poisson(ZIP)regression model to explore the important environmental factors that affect individual distribution. The results were as follows:(1)size-class distribution was “bell-shaped”, the number of small size-class individuals was low, indicating that population regeneration was limited. P. kwangtungensis preferred the slopes and ridges with high altitude and steep terrain, showing a strong habitat specialization.(2)Spatial point pattern analysis(L function)presented that spatial distribution was significantly aggregated compared with null models, which might cause by dispersal limitation and habitat heterogeneity.(3)The ZIP regression model showed that high soil ammonium nitrogen, available potassium and low organic matter content associated with the occurrence of P. kwangtungensis (from 0 to 1), and the abundance(from 1 to N)was positively correlated with altitude, species diversity, and mean DBH, but negatively correlated with tree height, ammonium nitrogen, total phosphorus, and total potassium. The results indicate that the unstable size-class structure and intraspecific competition caused by spatial aggregation will accelerate the decline of the population, we suggest that the habitats with low soil nutrients at high elevations should be conserved preferentially, and reduce anthropogenic disturbance to maintain the original habitats. [ABSTRACT FROM AUTHOR]