Threshold of potential concern: an early way to identify the ecosystem structural thresholdsin a grazing gradient

Identification of ecosystem thresholds is a way to predict future changes and taking the best management practices in restoration processes. Thresholds are an integral part of nonlinear responses of ecosystemsto disturbances such as climate change or human activities. In this study,structural threshold of the total patch area and mean patch widthin a grazing gradient were identified using the nonlinear function and the concept of threshold of potential concern. Otherstructural featuresincludingnumber of grass, shrub and forb patches were also measured. The result showed that three-parametricsigmoid functions had the highestability to predict structural changes in ecosystem structurewithin a grazing gradient radiating out from the livestock stock night corral (camp). The result also showed that 1 to 2 Km radius from the livestock camp isthe critical threshold in ecosystem structure based on total patch area, landscape organization index and mean patch widthfitting to a sigmoid function.Generally, the area within 2 Km from the camp neededto receive emergency remedial management actions. The present study showed that the concept of threshold of potential concern is a useful and early way to predict the thresholds in the ecosystem for management actions.Also,the present study revealedthat three-parameter sigmoid function providesa much better fit to structural data than other nonlinear functions.