The response of vegetation dynamics of the different alpine grassland types to temperature and precipitation on the Tibetan Plateau

Abstract

The spatiotemporal variability of the Normalized Difference Vegetation Index (NDVI) of three vegetation types (alpine steppe, alpine meadow, and alpine desert steppe) across the Tibetan Plateau was analyzed from 1982 to 2013. In addition, the annual mean temperature (MAT) and annual mean precipitation (MAP) trends were quantified to define the spatiotemporal climate patterns. Meanwhile, the relationships between climate factors and NDVI were analyzed in order to understand the impact of climate change on vegetation dynamics. The results indicate that the maximum of NDVI increased by 0.3 and 0.2 % per 10 years in the entire regions of alpine steppe and alpine meadow, respectively. However, no significant change in the NDVI of the alpine desert steppe has been observed since 1982. A negative relationship between NDVI and MAT was found in all these alpine grassland types, while MAP positively impacted the vegetation dynamics of all grasslands. Also, the effects of temperature and precipitation on different vegetation types differed, and the correlation coefficient for MAP and NDVI in alpine meadow is larger than that for other vegetation types. We also explored the percentages of precipitation and temperature influence on NDVI variation, using redundancy analysis at the observation point scale. The results show that precipitation is a primary limiting factor for alpine vegetation dynamic, rather than temperature. Most importantly, the results can serve as a tool for grassland ecosystem management.

Spatial-Temporal Patterns and Controls of Evapotranspiration across the Tibetan Plateau (2000–2012)

“…∘ 19 -104 ∘ 47 E and 26 ∘ 00 -39 ∘ 47N, which covers an area of 2.5 million km 2 , is the highest plateau in the world, and it has been called the roof of the world and the third pole of the Earth [45,46]. The Tibetan Plateau, located in southwest China, features several climate types.…”

The Influences of Climate Change and Human Activities on Vegetation Dynamics in the Qinghai-Tibet Plateau

“…The growing season NDVI of the steppe is driven by both temperature and precipitation [29]. In addition, effects of precipitation and temperature on vegetation growth have been found to exhibit strong spatial heterogeneity throughout the arid and semi-arid regions [30,31]. In the headstream region of Yangtze River, overgrazing has resulted in severe grassland degradation [32], whereas at the same time some researchers have pointed out that light-intensity grazing improves alpine meadow productivity and promotes adaptation to environment change on the plateau [33].…”

Weakening Relationship Between Vegetation Growth Over the Tibetan Plateau and Large‐Scale Climate Variability

“…Second, we analyzed the temporal changes in the interannual relationships between regional vegetation growth and large‐scale climate variability by taking the TP as a whole, but in reality there might be divergent response patterns in such relationships among different vegetation types. Indeed, previous studies have revealed that the responses of vegetation growth to historical hydrothermal variability might be dependent on vegetation type (Brown et al, ; Cuo et al, ; Gouveia et al, ; Hu et al, ; Sun et al, ), with increases in vegetation growth mainly occurring in alpine steppe and alpine meadow, and decreases in vegetation growth in desert steppe over the TP (Cuo et al, ). How changes in large‐scale climate variability interacting with diverse climate responses of different plant functional groups will reshape the spatiotemporal patterns in terrestrial ecosystem functioning, as well as the consequent biophysical climate feedback, particularly facing a much warmer and more extreme climate regime, needs further investigation.…”