Search

The threshold effect of the change of canopy and shrub & grass cover during vegetation restoration often determines the success or failure of ecological restoration. If this effect is ignored, other ecological problems may arise. In order to further promote the restoration of forest ecosystems in China and fill in the relevant research gaps, we study the dynamic characteristics of vegetation coverage of tree layer and shrub & grass layer under natural and artificial restoration patterns in typical red soil regions. Based on the advanced ecological threshold assessment framework, we evaluated the threshold effects between the two coverage indicators for different recovery modes through the linear model and three threshold models (including piecewise regression models, step function models, and general models). The results show that, according to the form of posterior distribution of the ecological threshold, there is a threshold effect between the canopy cover and shrub & grass cover under artificial restoration, but it does not exist in the natural recovery mode. Compared with the accuracy of the evaluation results of each model, the results of the hockey stick (HS) model are more accurate. Using the HS model, the threshold of canopy cover in the current artificial restoration plot is 42.85% (95% confidence interval is 41.57%-44.13%), and the shrub & grass cover is 58.75%. If the threshold is crossed, the coverage of the shrub & grass will begin to decrease. Our results can provide an important scientific basis for the structural improvement of plantation ecosystem in red soil region of China. [ABSTRACT FROM AUTHOR]