基于MODIS NPP数据的青海湖流域产草量与载畜量估算研究

Estimating grassland yield and carrying capacity in Qinghai Lake Basin based on MODIS NPP data

快速评价区域草地生产力状况,是制定牧区草畜平衡策略,保障草地生态系统健康可持续发展的前提基础。基于MODIS NPP产品数据,对青海湖流域草地生产力进行了估算和评价。结果表明:(1)牛羊可食性最高的高寒草甸、高寒草原和温性草原,其单位面积产草量估算值的均方根误差RMSE为26.15g·m^-2,表明该方法可以快速估算区域尺度的产草量。(2)全年干草产量为145.42万t,其中能被牛羊直接采食利用的牧草共计59.18万t,理论载畜量为81.07万羊单位;(3)影响单位面积干草产量的主要气候因子,海拔3500 m以下地区,是活动积温且与单位面积干草产量呈负相关关系;3500 m以上地区,是温度且与单位面积产草量呈正相关关系。研究结果可为高寒地区合理规划牧业生产活动、生态补偿等提供科学依据和决策支持,也可为全国其他牧区的草原产草量的估算提供参考。

Fast evaluating grassland productivity is critically significant to make a balancing development strategy between grassland and livestock in pastoral areas, as well as promoting the healthy and sustainable development of grassland ecosystems. Based on the NPP products of MODDIS, the grassland productivity was estimated in the Qinghai Lake Basin. The results showed that:(1)The RMSE of the estimated grass yield per unit of alpine meadow, alpine grassland and warm grassland with the highest edible degree of cattle and sheep was 26.15 g·m^-2, which indicated that the method could be used to quickly estimate the grassland yield in a regional scale.(2) The annual hay yield in the Qinghai Lake Basin was 1454200 tons, of which 591800 tons could be directly eaten by cattle and sheep;theoretical stock-carrying capacity was 810,700 sheep unit.(3) In the areas below the altitude of 3500 m, the accumulated temperature was the main factor that affected hay production per unit, and their correlation was negative. While above 3500 m, temperature was the main factor;the relationship between the factor of temperature and the hay production per unit was positive. The research results can provide scientific basis and supportive strategies for the planning of livestock production activities and ecological compensation in the alpine regions.