Recent responses of grassland net primary productivity to climatic and anthropogenic factors in Kyrgyzstan

Abstract

Net primary productivity (NPP) is an essential indicator of ecosystem function and sustainability and plays a vital role in the carbon cycle, especially in arid and semiarid grassland ecosystems. Quantifying trends in NPP and identifying the contributing factors are important for understanding the relative impacts of climate change and human activities on grassland degradation. For our case-study of Kyrgyzstan, we quantified from 2000 to 2014 the spatial and temporal patterns in climate-driven potential NPP (NPP P) using the Zhou Guangsheng model specifically developed for Asian grasslands, and actual NPP (NPP A) using the globally calibrated MOD17A3 NPP data product. By calculating the difference between NPP P and NPP A , we inferred human-induced NPP (NPP H) and thereby characterized changes in grassland NPP attributable to anthropogenic activities. The results showed that grassland NPP A in Kyrgyzstan experienced a slight decrease over time at an average rate of −0.87 g CÁm −2 Áyr −1 but patterns varied between provinces. Nearly 60% of Kyrgyzstan's grass

Assessment of Spatio-Temporal Variation and Driving Mechanism of Ecological Environment Quality in the Arid Regions of Central Asia, Xinjiang

“…It can make up for the deficiency of traditional semi-quantitative ecological evaluation methods and provide an effective research method for regional ecological evaluation, and thus many scholars have studied ecological environment monitoring and assessment based on remote sensing methods [10]. In the selection of an ecological environment remote sensing monitoring index, some studies evaluated the ecological environment by a single index, such as using the net primary productivity (NPP) index to evaluate grassland ecology [11], using the land surface temperature (LST) to assess urban heat islands [12][13][14], using green vegetation fraction (GVF) to estimate the ecological status and its changes in the riparian zone [15], or using impervious surface coverage to evaluate the urban ecological environment [16]. Although a single index is easy to understand and easy to calculate, the ecological environment is a complex system in the existing ecosystem, and the ecological environmental quality is controlled by multiple ecological factors [17], leading to difficulties in characterizing the quality of the ecological environment by only a single ecological factor [18].…”

Quantifying responses of net primary productivity to agricultural expansion in drylands

“…Humans influence NPP through transformation activities that improve production and livelihoods of which land use/cover change (LUCC) is the most human‐specific activity (Li, Meng, Zhu, & You, 2020). The increase in population and corresponding material demand has meant that the scope of human ecological impacts has considerably increased, which has brought many potential ecological and environmental problems (Ren and Zhou, 2018; Wang, Yue, Peng, He, & Bryan, 2020). The scarce precipitation and lack of water resources imply that the dryland ecosystem is extremely fragile and sensitive to LUCC (Huang, Xia, Wang, et al, 2018).…”

Remote Sensing of Pasture Degradation in the Highlands of the Kyrgyz Republic: Finer-Scale Analysis Reveals Complicating Factors

“…The Kyrgyz Republic (Kyrgyzstan) is a small, highly mountainous nation of~6.5 million in 2019, where more than 60% live in rural areas and where agropastoralism is the predominant land use [1]. Degradation of pasture resources in highly mountainous Kyrgyz Republic has been both widely reported [2][3][4][5][6][7][8] and disputed [9,10]. Many studies have attempted to detect land degradation in Central Asia by using remote sensing products based on finer temporal but coarser spatial resolution imagery [4,7,8,[11][12][13][14][15][16].…”

“…Degradation of pasture resources in highly mountainous Kyrgyz Republic has been both widely reported [2][3][4][5][6][7][8] and disputed [9,10]. Many studies have attempted to detect land degradation in Central Asia by using remote sensing products based on finer temporal but coarser spatial resolution imagery [4,7,8,[11][12][13][14][15][16]. While the finer temporal resolution products are better able to obtain clear views of the land surface, coarser spatial resolution products blend together heterogeneous surfaces.…”

“…Untangling the differential influences of climate and human activity is complicated by coarser spatial resolution [7,14,20]. Pastoralism in Kyrgyzstan is characterized by transhumance, the seasonal movement of livestock to fresh pastures, and vertical transhumance in particular, where the herds are moved from low-elevation winter pastures near villages through transitional pastures in spring (and again in fall) to higher elevation summer pastures distant from settlements.…”