The Response of Plant Species Diversity to the Interrelationships between Soil and Environmental Factors in the Limestone Forests of Southwest China

Abstract

An understanding of the spatial patterns of plant diversity is essential in deciding conservation priorities. Identifying these patterns may rely on our ability to predict how species respond to environmental variables. The present study examined plant species diversity variations and their ecological correlates in the limestone forest of Longhushan Nature Reserve, SW China. Species diversity was examined using statistical analyses and modellings to establish its response to the single or combined influence of the environmental habitat factors. The results showed that variations in diversity were dependent on complex relationships between karst habitat factors. The geological factor played an important role as its inclusion in the analysis with soil and environmental factors greatly improved the overall predictability of plant diversity. Species diversity was significantly predicted (F=13.330, p<0.001) with over 79% of its variance explained by the model (adjusted R²=0.794). Trends in diversity were mainly related to moisture, rock type in association with slope gradient and temperature. The influence of rock type was related to dolomite as diversity had a positive trend in high dolomite percentage areas and the inverse trend in calcium rich areas. The dominant species responded differently to the significant factors, but a number of those species were found typically well adapted to the special karst habitats. Sterculia nobilis, Albizia chinensis, Ficus oligodon, and Psychotria rubra were found adapted to all habitats conditions, suggesting they could be appropriate species for restoration and forest amelioration measures. It was clearly demonstrated that the evidence of significant variations in species diversity was provided after combining variables from soil, geological, and environmental factors, suggesting their interactions influence on plants.

Keywords: plant species diversity, rock type, soil characteristics, environmental factors, interactions, karst forest