Species abundance distribution characteristics of forest communities and its relationship with elevation in Longwangshan, Zhejiang

Abstract

Species abundance distribution (SAD) combines species richness with species abundance in a community and is an important indicator of community structure. Although many studies have applied mathematical models to fit the SADs of plant communities, there are still few studies on the changes in the shape of SAD (i.e., the skewness of the SAD curves) along the environmental gradient. Especially for forest communities, it is still unclear whether the model fitting and shape change of SADs are consistent in different vegetation types. Here, 28 plots of 20 m × 20 m were set up in Hynobius amjiensis National Nature Reserve according to the main forest vegetation types. The species composition and abundance of each species were surveyed in each plot. The logseries model and the lognormal model were fitted to the SAD in each plot, and then the best-fit model was selected based on the corrected Akaike's Information Criteria (AICc). The α value in Gambin model and the η value in Weibull model were calculated to reflect the shape of SAD in each plot. The λ value in Weibull model was calculated to reflect the scale of SAD (i.e., the range observed in abundance). The relationship between altitude and the shape and scale of SAD was analyzed. The results were as follows: (1) The logseries model fitted SAD better than the lognormal model. (2) When all plots were included, there was no significant correlation between SAD shape (α and η) and altitude, but there was a significant positive correlation between the λ value and altitude. (3) There was a negative correlation between altitude and α and η values in the mixed evergreen and deciduous broad-leaved forests, and there was a significant positive correlation between the α value and altitude in the deciduous broad-leaved forests, while there was no significant correlations between both α value and η value and altitude. The results indicate that the model fitting and shape change of SADs along the environmental gradient are related to the vegetation types of the forest community. Therefore, it is necessary to consider the vegetation types when analyzing the relationship between SAD and impact factors in plant communities.

Keywords

• subtropical forests
• community structure
• species abundance distribution
• models
• vegetation types
• longwangshan