Whether species diversity and genetic diversity change in parallel through time in disturbed systems is an important issue in community genetics. Although several recent studies reported that species diversity and genetic diversity showed similar changes following disturbance in organisms with short lifecycle, few have investigated in long-lived organisms.

The species-genetic diversity correlations (SGDCs) and their underlying mechanisms in natural and disturbed forests have been studied by scientists at Wuhan Botanical Garden, Chinese Academy of Sciences. Dr. WEI Xinzeng and Prof. JIANG Mingxi compared species diversity, the genetic diversity of the dominant tree species Euptelea pleiospermum, the altitudinal patterns of species diversity and genetic diversity, and SGDCs between mountain riparian forests along the Yandu (natural) and Nan (disturbed) rivers in the Shennongjia Mountains. In natural forests, both species diversity and genetic diversity showed a unimodal altitudinal pattern and genetic diversity was positively correlated with species diversity, whereas the unimodal pattern and positive SGDC were not found in the disturbed forests.

The results suggested that a correlation between the patterns of species diversity and genetic diversity along altitude gradients is an important driver of positive SGDC. The absence of positive SGDC in the disturbed forests may result from reduced species diversity but unaffected genetic diversity, indicating nonparallel changes of species diversity and genetic diversity. In addition, this study cautiously objected the generalizations about changes of species diversity and genetic diversity following disturbance.

The study entitled “Contrasting relationships between species diversity and genetic diversity in natural and distributed forest tree communities” has been published  in New Phytologist (doi: 10.1111/j.1469-8137.2011.03957.x). This research was founded by National Natural Science Foundation of China (Nos. 30670368 and 31070465).

 Figure legend Relationships between plant species diversity and genetic diversity of Euptelea pleiospermum along the Nan (disturbed) and Yandu (undisturbed) rivers. (a) Correlation between species richness (S) and allelic richness (A_R). (b) Correlation between Simpson’s diversity index (D) and expected heterozygosity (H_E) (Image by WEI Xinzeng)