Affiliations: College of Forestry, Sichuan Agricultural University,
Ya&'an 625000, Sichuan, China | Chengdu Institute of Mountain Hazards and
Environment, CAS, Chengdu 610047, Sichuan, China
Abstract: The upper Yangtze River basin, as an ecological protection screen
for the whole Yangtze River, is a key ecological region in China. It is a
substantial basis to assess the water conservation function of grassland
ecosystem for sake of nature conservation, flood control and ecological
regionalization. Through an integrated analysis on vegetation classification
system and land-use changes, this study conducted a merger of various
grasslands into eight assessment units. Interception (depth) under a single
rain was formulated as the key indicator to evaluate water retention capacity
of various grassland types. The results showed that the water-retention depth
of grassland ecosystems within a single rainfall in the study area ranges from
17.25 mm to 40.65 mm, averaging 24.58 mm, among which the temperate-grass and
forb meadow steppe had the highest capacity of water retention whereas the
grass and Kobresia forb swamp meadow had the lowest capacity. A total amount of
conserved water in the grassland ecosystems amounted to 45.67 × 10^8
m^3, pricing as $3.657×10^8. On spatial variances, the water-source
area, which locates at eastern Qinghai-Tibetan Plateau, comes out to be the
most important region whereas areas of Hengduan mountain region, northeastern
Yunnan-Guizhou Plateau and eastern mountain ranges around Sichuan Basin co-form
a generally important region.
Keywords: The upper Yangtze River basin, grassland ecosystem, water conservation, function assessment
