Changes of leaf functional traits in karst rocky desertification ecological environment and the driving factors

Abstract

Karst rocky desertification (KRD), a degraded land form, has seriously damaged the balance and stability of the ecosystem. Plant functional traits reflect the response and adaptation of plants to the growth environment. However, little is known about the effects of ecological environment of KRD on plant functional traits. To explore plant ecological strategies and driving factors in ecological environment of KRD, the plants in three study areas of rocky desertification of South China Karst were selected as the study objects. The relationships between the leaf functional traits and plant characteristic (growth form) and environmental factors (climate, soil, lithology, landform, growth form and degree of KRD) were statistically analyzed. The results show that: As the transition of constructive species from herbs and liana to arbors, leaf thickness (LT), leaf area (LA) and leaf carbon content (LCC) showed an increasing trend, while specific leaf area (SLA), transpiration rate (Tr) and leaf phosphorus content (LPC) showed a gradually decreasing trend. After feature extraction by PCA, the different growth forms of plants were divided into three types: quick-gain type (herb and liana); slow-gain type (arbor); transitional type (shrub). The plant ecological strategies of different ecological environments of KRD are also different. The plants in the moderate-intense KRD area belong to the quick-gain type, while those in the non-potential KRD area belong to the slow-gain type. Variance partitioning showed that plant characteristic and environmental factors explained the change of leaf functional traits by 5% and 31%, respectively. Our study shows that environmental factors contribute more to the shaping of leaf functional traits than plant characteristic in KRD area. Among the environmental factors, average annual temperature, average annual precipitation, pH and degree of KRD are the main influencing factors for the change of leaf functional traits in ecological environment of KRD.