Effects of climate change and human activities on net primary production of wetlands on the Zoige Plateau from 1990 to 2015

Wetlands are vulnerable to climate change and human activities. However, the past changes caused by climate and human activities on net primary production (NPP) were unclear on the Zoige Plateau, which is on the Qinghai-Tibet Plateau. In this study, the impact of climatic and anthropogenic pressure on the NPP of wetlands on the Zoige Plateau from 1990 to 2015 was explored. We assessed and quantified the effects of climatic and anthropogenic factors on NPP using a simulated process model (LPJ_WHyMe) and a remote sensing model (CASA). Our simulations suggested that the annual average potential net primary production (NPPp) fluctuated during the study period and peaked in 2008 (347.37 g C m-2 year-1), while the total wetland NPPp peaked in 2000 (1.75 Tg C year-1). The results also showed that the annual average actual net primary production (NPPa) reached the lowest value of 206.04 g C m-2 year-1 in 2000. The total wetland NPPa ranged from 0.97 to 1.15 Tg C year-1 and continuously decreased over the study period. Our research revealed that human activities accounted for 22.37-36.45% of wetland NPP reduction over the study period. These results suggested that reducing human interventions can improve the NPP of wetlands. However, some of the negative effects of human activities have been offset by ecological restoration projects. These results provide a reference and scientific support for wetland protection and sustainable development.