Elevation and Climate Effects on Vegetation Greenness in an Arid Mountain-Basin System of Central Asia

Abstract

Mountain-basin systems (MBS) in Central Asia are unique and complex ecosystems, wherein their elevation gradients lead to high spatial heterogeneity in vegetation and its response to climate change. Exploring elevation-dependent vegetation greenness variation and the effects of climate factors on vegetation has important theoretical and practical significance for regulating the ecological processes of this system. Based on the MODIS NDVI (remotely sensed normalized difference vegetation index), and observed precipitation and temperature data sets, we analyzed vegetation greenness and climate patterns and dynamics with respect to elevation (300–3600 m) in a typical MBS, in Altay Prefecture, China, during 2000–2017. Results showed that vegetation exhibited a greening (NDVI) trend for the whole region, as well as the mountain, oasis and desert zones, but only the desert zone reached significant level. Vegetation in all elevation bins showed greening, with significant trends at 400–700 m and 2600–3500 m. In summer, lower elevation bins (below 1500 m) had a nonsignificant wetting and warming trend and higher elevation bins had a nonsignificant drying and warming trend. Temperature trend increased with increasing elevation, indicating that warming was stronger at higher elevations. In addition, precipitation had a significantly positive coefficient and temperature a nonsignificant coefficient with NDVI at both regional scale and subregional scale. Our analysis suggests that the regional average could mask or obscure the relationship between climate and vegetation at elevational scale. Vegetation greenness had a positive response to precipitation change in all elevation bins, and had a negative response to temperature change at lower elevations (below 2600 m), and a positive response to temperature change at higher elevations. We observed that vegetation greenness was more sensitive to precipitation than to temperature at lower elevations (below 2700 m), and was more sensitive to temperature at higher elevations.

Vegetation Changing Patterns and Its Sensitivity to Climate Variability across Seven Major Watersheds in China

“…On one hand, different vegetation types have different vegetation–climate relationships, resulting in different changing patterns in vegetation [ 66 ], which makes it reasonable to evaluate vegetation changes and their link with climate within different ecosystems [ 47 ]. On the other hand, topographic attributes, including elevation, slope, and aspect, introduce heterogeneity into the effects of water availability, radiation, and temperature on vegetation greenness [ 44 , 67 , 68 ]. It can be seen in Figure 4 that the source regions of the YZRB and YRB were divided into three sub-regions (Regions VII, X, XI) by elevation.…”

Vegetation dynamics in the Madiwatershed, Gandaki Province of Nepal

“…Himalayan mountains are a unique and complex ecosystem, where elevation controls spatial heterogeneity in vegetation due to the large climatic variation in a short spatial distance (Tai et al 2020). The degradation of vegetation by human consumption is one of the most important parts of the distribution of vegetation intensity and biomass.…”

Response of Vegetation Photosynthetic Phenology to Urbanization in Dongting Lake Basin, China

“…For different vegetation types, the evergreen broadleaf forests are widespread in lower elevations where human activities were frequent and more accessible to urban. Due to the higher background temperatures there, vegetation has adapted to the environmental changes, making the phenology less sensitive to urbanization [51], while the evergreen coniferous forests, shrubs, and grasslands at higher elevations may be more sensitive to the increase in temperature caused by the UHI phenomenon [52].…”