Species coexistence and the maintenance of biodiversity  is always the hot topic of community ecology. As the base of Species diversity maintaining mechanism, species distribution patterns are affected by spatial distribution, species attributes, and habitat heterogeneity. Inferring the processes underlying the spatial distribution patterns of tree species is fundamental for understanding species coexistence.  

Vegetation Ecology Research Group, led by JIANG Mingxi, from Wuhan Botanical Garden examined spatial distribution patterns of woody plants by using the univariate pair correlation function to quantify spatial patterns of species in a fully mapped 25 ha subtropical  permanent dynamic plot in China. They analyzed the relationships between the species attributes and spatial distribution patterns of 137 tree species with at least one individual per hectare.  

The results showed that aggregated distributions were the dominant pattern for species in the Badagongshan subtropical forests, and that the percentage of significantly aggregated species decreased with increasing spatial scales. Rare species were more aggregated than intermediate and abundant species, but they were more easily influenced by habitat heterogeneity. Also, there was significantly negative relationship between species abundance and species aggregation intensity. The aggregation intensity showed negative relationships to species mean diameter at breast height (DBH) and maximum DBH. Species functional traits (e.g., growth form and phenological guild) also had obvious effects on the spatial patterns of species. However, spatial patterns of tree species were not related to the dispersal mode.  

Their results partially conformed to the prediction that species’ attributes influenced species’ spatial patterns following similar laws, even after controlling for the effects of habitat heterogeneity. Consequently, species attributes (species abundance, mean DBH, maximal DBH, growth form, phenological guild, etc.) and habitat heterogeneity may primarily contribute to spatial patterns and species coexistence in natural forests. 

This study was supported by the National Natural Science Foundation of Chinaand the Chinese Forest Biodiversity Monitoring Network. Results were published in Can. J. For. Res. (2013, 43: 826–835) entitled “Spatial distribution of tree species in a species-rich subtropical mountain forest in central China”.