The potential for using rare, native species in reforestation– A case study of yews (Taxaceae) in China

Abstract

Ecosystem restoration is regarded as one of the most cost-effective ways of mitigating the effects of the ongoing climate- and anthropogenic changes and slow or revert the loss of biodiversity. Forest restoration has much potential to conserve forest specialist species and ecosystem services, by using multiple, native tree species to promote a high local diversity of trees, with likely positive effects on overall biodiversity and on ecosystem resilience. In this study, we assessed the potential of using two rare, native species of the yew family (Taxaceae) in forest restoration in China. Species of this family are only rarely used in reforestation despite their potential contribution to tree functional diversity as long-lived, shade-tolerant, evergreen understory trees with fleshy seed cones of value to frugivorous animals. By using species distribution modelling methods, we analysed national and local scale occurrence data for Taxus cuspidata and Torreya grandis to determine the climate-based potential ranges as well as important factors for growth on a local scale. The analyses showed that both species have large potential ranges driven mainly by precipitation and by comparing these ranges with the areas that have potential for sustaining forests, we found large areas available for forest restoration where these species could be included. On the local scale, we found that low light levels and low competition from co-occurring trees are more important for the growth of seedlings compared to the adult individuals of both species. If the ecological requirements for seedlings are ensured, i.e. by creating moderately shaded environments in which seedlings can escape competition, both Taxaceae species have high potential for reforestation in China and will increase the ecological qualities of a restored forest, and at the same time, the conservation of rare tree-species in their native ranges is ensured. Conclusively, both Ta. cuspidata and To. grandis are shade-tolerant, slow-growing trees that, by creating an evergreen scrubby layer, add to forest structural complexity and stability, thereby helping support ecosystem services and biodiversity, e.g. microhabitat and resources for birds and other animals.