The Classification Indices-Based Model for NPP According to the Integrated Orderly Classification System of Grassland and Its Application

2014

54 S.

Artikel aus einer ZeitschriftUnselbständiges Werk

200183062

Grassland accounts for 25% of the world s land area and has global significance for climatecarbon feedback [1]. As one of the most widespread ecosystem types, grassland makes a large contribution to carbon sequestration and plays a significant role in regional climates and the global carbon cycle [2]. Grassland net primary productivity (NPP) refers to carbon accumulation (photosynthesis less respiration) in grassland per unit of time, and can be used as an indicator of the capacity of the grassland ecosystem to accumulate carbon and to support grazing animals. Studies of the NPP have contributed significantly to our understanding of the pattern, process and dynamics of grassland ecosystems. Hence, the accurate estimation of the NPP of grasslands is very important not only for scientifically guiding grassland management but also for understanding the global carbon cycle. Reliable long-term data on grassland NPP are urgently needed to estimate carbon fluxes. Due to their time- and labor-intensive nature, ground measurements of grassland NPP are very limited in temporal and spatial coverage. The precision evaluation of NPP estimated in regional or global scales is always very difficult. Direct measurement of grassland NPP is tedious and not practical for large areas, so it is therefore appropriate to use computer models, calibrated with existing data, to study the spatial and temporal variations of grassland NPP [3]