Changes in CSR Ecological Strategies of Plants and Communities Following the Introduction and Restoration of Woody Plants in Semi-arid Damaged Steppe Grasslands

Abstract

Hulunbuir steppe, one of the four largest grasslands in the world, is suffering progressing desertification due to climate change and anthropogenic disturbance. In this study, the plant species and communities were analyzed with CSR ecological strategies for the succession process that occurred following the introduction of woody plants in the restored site in the damaged steppe, and compared with those in the reference site in an attempt to find the lifeform characteristics of plants in grasslands and implications for success in ecological restoration. According to the results, the introduction of woody plants into the damaged land greatly increased the diversity of plant species and CSR eco-functional diversity as the succession progressed. The types of ecological strategies of the temperate typical steppe (TTS) and woodland steppe (WS) in this region are CSR and S/SR, respectively, which means that plants in the temperate Asian steppe are species basically adapted to natural disturbances such as drying and soil movement. As the restoration time elapsed in the damaged lands (R/CR), the ecological strategies were predicted to change in two ways: R/CR→R/CSR→CSR (TSS) in places where only shrubs were introduced, and S/SR→S/SR (WS) in places where trees and shrubs were introduced simultaneously. The results as such mean that the driving force that causes succession in the restoration of temperate grasslands is determined by the lifeform (trees/shrubs) of the introduced woody plants, and therefore, it is judged that trees or shrubs should be selected and introduced bearing the final target vegetation in mind when planning restoration.