Ecological Indicators (Jul 2022)
Management practices should be strengthened in high potential vegetation productivity areas based on vegetation phenology assessment on the Qinghai-Tibet Plateau
Abstract
Climate change and human activities have severely affected the structure and function of vegetation on the Qinghai-Tibet Plateau (QTP). Management practices have contributed to vegetation growth on the QTP, yet the response of vegetation productivity to management during the growing season remains unclear. Here, a fitted sixth-degree polynomial function was used to extract phenology-based vegetation productivity, which was quantified as the integrated normalized difference vegetation index (INDVI) over the length of the season during 2000–2019. Additionally, a new management practice intensity indicator was established to quantify the degree of ecological project and policy effectiveness on vegetation productivity. Three main results were obtained: (1) On a pixel-by-pixel basis, phenology-based vegetation productivity can avoid the impact of start-of-season (SOS) and end-of-season (EOS) variations. Vegetation productivity increased over 66% of the area of the QTP during 2000–2019, and the area with a significant increasing trend in vegetation productivity accounted for 9.15% of the QTP, including 5.65% in grassland and 0.23% in cultivated land. (2) Areas of increased vegetation productivity, grassland productivity, and cultivated land productivity affected by the positive impact from climate change accounted for 23.76%, 16.61%, and 0.31%, respectively, while they accounted for 41.29%, 28.10%, and 0.59% for human activities, respectively. (3) The regions of high-level management practice intensity accounted for 26.51% of the QTP but only 2.57% and 0.03% of grassland and cultivated land productivity, respectively. The regions of decreased grassland productivity still accounted for 21.85% of the QTP. Therefore, improving vegetation management practice intensity on grassland can increase regional vegetation productivity. These findings can provide effective guidance for regional vegetation management.
