Topographic Factors Drive Short-Term Understory Revegetation in Burned Areas

Abstract

Fire is a disturbance factor in forest ecosystems which has an important influence on vegetation succession. In order to reveal the natural recovery characteristics of the understory vegetation and its response to topographic factors (elevation, slope position, aspect and slope) after fire in subtropical forests, a typical subtropical forest (Xide County, China) was selected as the study area. Based on quadrat surveys and correlation analyses, the main results of this study were as follows. (1) Within four months after a fire, a total of 71 species, 52 genera and 20 families of understory vegetation species were increased, representing a rapid recovery after a fire. The total number of genera and species of understory vegetation increased by 157% and 209%, respectively. (2) Different burning intensities had different effects on the recovery of vegetation species diversity. The change in Margalef richness index was the most significant, increasing by 5.44 and 5.16 in lightly and severely burned areas, respectively. (3) The vegetation community could be divided into six types after restoration. (4) Elevation and slope were significantly correlated with the diversity and distribution characteristics of understory vegetation in the burned area. This study is useful to understand the characteristics of the short-term natural recovery of understory vegetation in subtropical forests after fire, to identify the relationship between vegetation and topographic factors in burned areas, and to provide a scientific basis for vegetation recovery.