Abstract:

It is significant for revealing the water conservation functions of different ecosystems to study the spatial variation characteristics of the water conservation function in Picea crassifolia forests in the Qilian Mountains and to determine the hydrological allocation effects of different ecosystems. This research statistically analyzed ecohydrological spatial monitoring data from the Pailugou watershed in the Qilian Mountains， using regression， fitting， and significance testing methods. The results showed that： （1）Precipitation increases with elevation between 2 600-3 300 m， peaking at 3 300 m before decreasing above this altitude， which presented as a polynomial correlation in the entire space. The increase rate at every 100 meters is 6.91% from 2 600-3 200 m， while the decrease rate at every 100 meters is 6.53% from 3 200-3 800 m. （2） For P. crassifolia forest， the average interception ratio was between 34.41% and 48.35%. The interception ratios were 43.74%， 34.41%， 46.48%， and 48.35% when the canopy density were 0.77， 0.61， 0.85， and 0.86， respectively. At the elevation of 2 600-2 950 m， the interception ratio was increased with the increasing of throughfall， presented as a linear increase trend. （3） For shrub， the average interception rate is 55.21%， the average interception amount is 5.19 mm， and the average throughfall amount is 5.15 mm. （4） For moss， the average interception ratio was 68.66%， the precipitation reached 9.48 mm； the interception rate in most areas is around 50%. （5）There was a significant linear positive correlation between precipitation and interception amount （R²=0.991， P<0.01）， while a significant increasing logarithmic relationship with interception rate （R²=0.7844， P<0.05）. The research has found that the order of interception is moss> shrub>Picea crassifolia， highlighting the exceptionally strong water conservation functions of moss.

Key words: water conservation function, spatial change, Picea crassifolia, Qilian Mountains