Next Article in Journal
Designing Aquaponic Production Systems towards Integration into Greenhouse Farming
Previous Article in Journal
Three-Dimensional Numerical Method for Simulating Large-Scale Free Water Surface by Massive Parallel Computing on a GPU
Previous Article in Special Issue
Identifying Sensitive Model Parameter Combinations for Uncertainties in Land Surface Process Simulations over the Tibetan Plateau
Open AccessArticle

Effects of the Freezing–Thawing Cycle Mode on Alpine Vegetation in the Nagqu River Basin of the Qinghai–Tibet Plateau

1
State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research (IWHR), Beijing 100038, China
2
School of Water Conservancy and Hydroelectric Power, Hebei University of Engineering, Handan 056021, China
3
College of the New Energy and Environment, Jilin University, Changchun 130021, China
4
Institute of Water Resources and Hydrology Department of Hydraulic Engineering, Tsinghua University, Beijing 100084, China
*
Author to whom correspondence should be addressed.
Water 2019, 11(10), 2122; https://doi.org/10.3390/w11102122
Received: 30 July 2019 / Revised: 6 October 2019 / Accepted: 9 October 2019 / Published: 13 October 2019
The freezing–thawing cycle is a basic feature of a frozen soil ecosystem, and it affects the growth of alpine vegetation both directly and indirectly. As the climate changes, the freezing–thawing mode, along with its impact on frozen soil ecosystems, also changes. In this research, the freezing–thawing cycle of the Nagqu River Basin in the Qinghai–Tibet Plateau was studied. Vegetation growth characteristics and microbial abundance were analyzed under different freezing–thawing modes. The direct and indirect effects of the freezing–thawing cycle mode on alpine vegetation in the Nagqu River Basin are presented, and the changing trends and hazards of the freezing–thawing cycle mode due to climate change are discussed. The results highlight two major findings. First, the freezing–thawing cycle in the Nagqu River Basin has a high-frequency mode (HFM) and a low-frequency mode (LFM). With the influence of climate change, the LFM is gradually shifting to the HFM. Second, the alpine vegetation biomass in the HFM is lower than that in the LFM. Frequent freezing–thawing cycles reduce root cell activity and can even lead to root cell death. On the other hand, frequent freezing–thawing cycles increase microbial (Bradyrhizobium, Mesorhizobium, and Pseudomonas) death, weaken symbiotic nitrogen fixation and the disease resistance of vegetation, accelerate soil nutrient loss, reduce the soil water holding capacity and soil moisture, and hinder root growth. This study provides a complete response mechanism of alpine vegetation to the freezing–thawing cycle frequency while providing a theoretical basis for studying the change direction and impact on the frozen soil ecosystem due to climate change. View Full-Text
Keywords: freezing–thawing cycle mode; aboveground and underground biomass; soil microbe; soil chemical properties; climate change freezing–thawing cycle mode; aboveground and underground biomass; soil microbe; soil chemical properties; climate change
Show Figures

Figure 1

MDPI and ACS Style

Man, Z.; Weng, B.; Yang, Y.; Gong, X.; Li, M.; Yu, Z. Effects of the Freezing–Thawing Cycle Mode on Alpine Vegetation in the Nagqu River Basin of the Qinghai–Tibet Plateau. Water 2019, 11, 2122.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop