Altitude explains insignificant autumn phenological changes across regions with large topography relief in the Tibetan Plateau

Nan Cong; Zhiyong Du; Zhoutao Zheng; Guang Zhao; Dongqi Sun; Jiaxing Zu; Yangjian Zhang

doi:10.1016/j.scitotenv.2024.171088

Altitude explains insignificant autumn phenological changes across regions with large topography relief in the Tibetan Plateau

Sci Total Environ. 2024 Apr 15:921:171088. doi: 10.1016/j.scitotenv.2024.171088. Epub 2024 Feb 21.

Authors

Nan Cong¹, Zhiyong Du², Zhoutao Zheng¹, Guang Zhao¹, Dongqi Sun³, Jiaxing Zu⁴, Yangjian Zhang⁵

Affiliations

¹ Lhasa Plateau Ecosystem Research Station, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
² Lhasa Plateau Ecosystem Research Station, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China.
³ Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
⁴ Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Ministry of Education, Nanning Normal University, Nanning 530001, China.
⁵ College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China; Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: zhangyj@igsnrr.ac.cn.

PMID: 38387561
DOI: 10.1016/j.scitotenv.2024.171088

Abstract

The start of the growing season (SGS) and the end of the growing season (EGS) are widely employed in global change studies to represent the spring and autumn phenology, respectively. Despite the Tibetan Plateau (TP) experiencing significant warming in recent decades, EGS has exhibited only slight changes. Previous studies have concentrated on exploring the environmental regulation of phenology, ignoring the distinctive influences of elevation. Therefore, a more in-depth investigation into the underlying mechanism is warranted. In this study, we investigate the variability of EGS among alpine vegetation regions at different elevations and conduct an analysis based on satellite data. Phenology data of alpine vegetation are extracted from SPOT NDVI dataset spanning from 1999 to 2018, using a piecewise-logistic-maximum-ratio method. We analyze the factors influencing EGS trends at different elevations. The results show that the overall insignificant variation in EGS is mainly attributed to altitude. With the altitude increasing, the annual mean EGS experiences a delay of 0.28 days/100 m below 3500 m, while it advances by 0.2 days/100 m above 3500 m. The opposing shift in elevation below and above 3500 m leads to this counteraction. Elevation emerges as the predominant factor influencing EGS trends, explaining the highest variations (38 %), followed by SGS (22 %) and precipitation (22 %). The elevation effect is most pronounced in areas with substantial topography fluctuations. Moreover, the elevation lapse rate of EGS (ELR_EGS) exhibits an opposite trend with growing season (GS) temperature and a similar trend with GS precipitation between the regions below and above 3500 m, ultimately linking to this counteraction. This study underscores elevation is a critical regulator of vegetation EGS responses to climatic changes over the TP, revealing significant spatial heterogeneities in these responses.

Keywords: Alpine vegetation phenology; Altitude differentiation; ELR_EGS; Inverse response to climate; Tibetan Plateau (TP).

MeSH terms

Altitude*
Climate Change*
Ecosystem
Seasons
Temperature
Tibet