The compound effects of highway reconstruction and climate change on
vegetation activity over the Qinghai Tibet Plateau: a case study as G318
highway
Abstract
:The Qinghai−Tibet Plateau (QTP) is among the most sensitive regions to
global environmental change worldwide. Although the climate change and
engineering construction on the QTP have jointly modified the regional
vegetation activity, little is known about how vegetation variation
responds. Using Moderate Resolution Imaging Spectroradiometer (MODIS)
enhanced vegetation index (EVI) data during 2000−2021, this study
investigated the spatiotemporal variation of vegetation activity and the
compound effects of climate change and construction along the G318
highway on the QTP (TG318) through the integration of trend, residual,
and partial correlation analyses, as well as structural equation
modeling. The results showed that the growing season EVI increased
significantly at a rate of about 0.0020/year in the western QTP after
reconstruction, but fluctuated in the east. Reconstruction generally had
a significant effect on the growing season EVI, with contributions of
7.67%, 19.12%, 18.24%, and −4.15% in different sections of TG318,
whereas climate change contributed −10.14% to 8.84% of the total
variation. The growing season EVI negatively correlated with snow cover
and minimum temperature in humid and sub-humid regions, whereas
positively related to vapor pressure in semi-arid regions. Moreover,
there existed an obvious lag effect of climate change on the growing
season EVI, with lag time generally decreasing from west to east and
apparent heterogeneity among different months and regions. These
findings would help better understand the environmental impacts along
the engineering corridors and provide a scientific basis for ecological
conservation in the QTP region.