Vegetation areas for which the trend of NDVI in summer for 1982–2006 is significant at the 0.05 level and their trend slope.

<p>Vegetation areas for which the trend of NDVI in summer for 1982–2006 is significant at the 0.05 level and their trend slope.</p

Vegetation areas for which the trend of NDVI in spring for 1982–2006 is significant at the 0.05 level and their trend slope.

<p>Vegetation areas for which the trend of NDVI in spring for 1982–2006 is significant at the 0.05 level and their trend slope.</p

Average growing season NDVI for 1982–2006.

<p>Average growing season NDVI for 1982–2006.</p

Average annual precipitation for different periods at three meteorological stations (unit: mm).

<p>Average annual precipitation for different periods at three meteorological stations (unit: mm).</p

Topography and river system of the Heihe River Basin.

<p>Topography and river system of the Heihe River Basin.</p

Annual river flows at the Yingluo Gorge and Zhengyi Gorge for 1981–2006 and their trend lines.

<p>Annual river flows at the Yingluo Gorge and Zhengyi Gorge for 1981–2006 and their trend lines.</p

Land cover in the Heihe River Basin.

<p>Land cover in the Heihe River Basin.</p