Response of Carbon Dynamics to Climate Change Varied among Different Vegetation Types in Central Asia

Abstract

The effect of climate change on the spatio-temporal patterns of the terrestrial carbon dynamics in Central Asia have not been adequately quantified despite its potential importance to the global carbon cycle. Therefore, the modified BioGeochemical Cycles (Biome-BGC) model was applied in this study to evaluate the impacts of climatic change on net primary productivity (NPP) and net ecosystem productivity. Four vegetation types were studied during the period 1979 to 2011: cropland, grassland, forest, and shrubland. The results indicated that: (1) The climate data showed that Central Asia experienced a rise in annual mean temperature and a decline in precipitation from 1979 to 2011; (2) the mean NPP for Central Asia in 1979–2011 was 281.79 gC m−2 yr−1, and the cropland had the highest NPP compared with the other vegetation types, with a value of 646.25 gC m−2 yr−1; (3) grassland presented as a carbon source (−0.21 gC m−2 yr−1), whereas the other three types were carbon sinks; (4) the four vegetation types showed similar responses to climate variation during the past 30 years, and grassland is the most sensitive ecosystem in Central Asia. This study explored the possible implications for climate adaptation and mitigation.

The Responses of the Ecosystems in the Tianshan North Slope under Multiple Representative Concentration Pathway Scenarios in the Middle of the 21st Century

“…A wetter trend is also detected by observations during the last several decades [9,10]. These climate changes play a very important role in the carbon and water flux dynamics of the arid ecosystems [11][12][13][14], and have drawn great concern about the sustainable development of the arid ecosystems. Due to the development of the industry and the intensive human activities, the observations from Mauna Loa show that the atmospheric CO 2 concentration has increased by 29.3% since 1959 and exceeded 400 ppm in 2015 [15].…”

“…Moreover, previous experimental and modeling studies have shown that arid ecosystems benefit from the increase of atmospheric CO 2 concentration, which is called the CO 2 fertilization effect [2,16,17]. However, different vegetation types have different responses to these changes resulting from the temporal and spatial heterogeneity of the climate change and the unique characteristics of each vegetation type [12,18]. Therefore, the dominant factor differs for each vegetation type.…”

“…On one hand, both NPP and ET are vulnerable to the changes in the climate and the atmospheric CO 2 concentration and the anthropogenic activities. Based on model simulations, Han et al [12] found that the annual NPP of grassland in arid Central Asia followed a decreasing trend (−0.21 g C m −2 year −1 ) from 1979 to 2011, resulting from the increase of annual mean temperature and the decline of precipitation. During the same period, the ET of grassland experienced significant declines of 1.47-2.72 mm per decade due to the climate change [25].…”

“…Previous studies mainly focused on the historical effects of changes in climate and/or CO 2 concentration on one or two elements (NPP, ET, and WUE) at a large scale [12,17,18,25,36]. How the fragile ecosystems in the arid area will respond to the future changes in climate and CO 2 concentration remains unclear.…”

Shifts of the Mean Centers of Potential Vegetation Ecosystems under Future Climate Change in Eurasia

“…Since the early 2000s, a continuous effort has been made to understand the relationship between vegetation distributions and climate change [28][29][30], especially to reveal the response of vegetation to climate change [31,32]. For instance, an analysis of the historical vegetation and climate data showed that the forest distribution had shifted to the polar region [33]; grass distribution was more sensitive to change than any other vegetation ecosystems in Central Asia [34]; the mean centers of the different terrestrial ecosystems in China showed different shift trends from 1960 to 2002 [35]; the mean center shift of vegetation ecosystem would influence the ecosystem service value [36]; and the mean centers of vegetation ecosystems would show a different shift trend under different climate change scenarios [37]. However, current research mainly focuses on the responses of the shift in the mean center of vegetation ecosystems to historical climate change [38], and is rarely involved in analyzing the response relations between the different shift trends of vegetation ecosystems and climate change in the future.…”