Changes in plant species diversity along a chronosequence of vegetation restoration in the humid evergreen broad‐leaved forest in the Rainy Zone of West China

Abstract Plant species diversity has been recognized as one of the vital attributes for assessing vegetation restoration. Changes in the diversity may be related to different stages of succession. In this study, 54 sites of humid, evergreen, broad‐leaved forest were selected in the Rainy Zone of West China. A chronosequence of the sites was used to study the successive patterns of the diversity in the forest that had undergone natural regeneration for 5 to 350 years and to test the hypothesis that the diversity is maximized in mid‐succession. Data were collected simultaneously at different stages of succession, and four α‐diversity indices (species richness, Margalef index, Shannon‐Wiener index, Pielou Evenness index) and two β‐diversity indices (Whittaker index, Sørensen's index) were calculated for each stratum in each plot. A total of 394 vascular plant species were recorded. From the β‐diversity indices, the forest succession may be divided into the early‐successional stage (before 50 years), mid‐successional stage (from 50 to 300 years), and late‐successional stage (after 300 years). In this community, the species diversity and richness were found to be the greatest at the mid‐successional stage, followed by the late‐ and early‐successional stages. The results of regression analysis indicated that the richness and Margalef index peaked around the 175th and 165th year, respectively. Shannon‐Wiener index values also appeared to follow an approximately humped pattern of succession and were maximal around the 100th year. However, the species evenness did not show any significant relationship with successional age. Our results demonstrate (1) forest restoration is a long‐term process and the formation of climax forest requires at least 300 years and (2) the forest has a strong capacity for restoration. Our results also suggest Lindera limprichitii and Machilus pingii as ideal tree species for afforestation because of their wide niche.