Publications

Zhang, XN; Nian, LL; Liu, XY; Samuel, A; Yang, YB; Li, XD; Liu, XL; Zhang, MM; Hui, CH; Wang, QX (2023). The spatiotemporal response of photosynthetic accumulation per leaf area to climate change on alpine grassland. GLOBAL ECOLOGY AND CONSERVATION, 43, e02467.

Abstract
Characterizing the photosynthetic capacity of grassland is essential for exploring the carbon cycle under climate change. However, little research has been conducted to date on photosynthetic accumulation per leaf area (NPP/LAI) in spatial and temporal terms, especially on how they respond to climate change. Hence, this study analyzed the spatiotemporal patterns of NPP/LAI based on MODIS products, explored the partial correlation of NPP/LAI with climatic factors for the annual and growing season, and quantified the time lag effects of climatic factors on NPP/LAI for seasonal in alpine grassland ecosystems at the source of the Yellow River Basin. The results indicated that NPP, LAI, and NPP/LAI of growing season increased in the study area between 2000 and 2021 whiles annual NPP/LAI decreased. At the same time, the spatial distribution of the multiannual mean values of precipitation and temperature approximately reversed and gradually increased on the time scale. The annual NPP/LAI for each grassland type gradually decreased between 2000 and 2021, with the mean of the growing season in NPP/LAI ranging from montane meadows (12.595 g C center dot m(-2)) > swamps (11.859 g C center dot m(-2)) > alpine meadows (11.718 g C center dot m(-2)) > temperate steppes (10.994 g C center dot m(-2)). It is also interesting to note that the mean values for montane meadows and alpine meadows were slightly higher in summer than in autumn, while the opposite was true for temperate steppes and swamps. Regarding the effects of climate, the response of NPP/LAI to temperature and precipitation varied among grassland types on an annual and seasonal basis. In addition, the seasonal lag effect of climate factors showed that the overall degree of effect of winter temperature on NPP/LAI in subsequent seasons increased as the seasonal interval progressed, while the opposite was true for precipitation, meaning that temperature affected NPP/LAI over a longer period compared to precipitation. Moreover, the seasonal time lag effects of climatic factors in different grassland types had varying degrees of influence on NPP/LAI, with the NPP/LAI of montane meadows and alpine grasslands being more closely related to climatic factors than those of temperate steppes and swamps. This study provides a basis for effective monitoring of photosynthetic capacity dynamics and helps develop policies to cope with climate change in alpine grasslands.

DOI:
10.1016/j.gecco.2023.e02467

ISSN:
2351-9894