Identification the spatial threshold of ecological indicator NDVI by application of optimal dividing algorithm for ordinal

Ecological threshold is the point or zone between alternate ecosystems. In the threshold, ecological process parameters, function and composition change fiercely, while they are relatively stable out of the threshold. Normalized Difference Vegetation Index (NDVI) is usually seen as an important indicator of eco-environment. The paper aims to identify NDVI threshold zone by use of the optimal dividing algorithm for ordinal specimen as the quantitative tool combined with qualitative discrimination principles. Results show that NDVI ecological thresholds are clearly discriminated and closely consistent with the actual landscape, optimal dividing algorithm is an effective tool for identifying the regional ecological threshold.