Response of vegetation characteristics in the alpine meadow ecosystem to simulated temperature enhancement——A case study of permafrost regions on the Qinghai-Tibet Plateau, China

Infrared heater was used to simulate temperature enhancement in the field focusing on the effects of temperature enhancement on the growth and photosynthetic characteristics of three alpine plants: Polygonum viviparum, Saussurea superb, and Carex atrofusca in order to provide basis for estimating the sensitivity and friability of the meadow ecosystem in the permafrost region on the Qinghai-Tibet Plateau, China. The results showed that the simulated warming W1 (1.88 ℃) and W2 (3.19 ℃) could all alter the distributing frequency and season pattern of the alpine plant species. Compared with the CK, the W1 temperature enhancement brought different changes to different plants under which the height, frequency and chlorophyll contents of the S. pulchra were decreased but the values of the P. viviparum and C. atrofusca were increased. The W2 warming evidently increased the height, frequency, and chlorophyll content of the P. viviparum and C. atrofusca but significantly (P<0.05) decreased the ratio of chlorophyll a to b of the S. pulchra resulted in its decreases in the height, frequency, and chlorophyll content. It showed significant differences in the photosynthesis indicators among the plant species, especially among the plots. All above indicates that the warming can improve the growth and development of the grazing plants in the alpine meadow and prolong their green grass duration resulting in benefit to the livestock production but the vegetation distribution evidently variegated.