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Elevational patterns of warming effects on plant community and topsoil properties: focus on subalpine meadows ecosystem

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Journal of Mountain Science 2024年第1期21卷 146-159页

作者： HAO Aihua LUO Zhengming CHEN Xiaojiang Department of Geography Xinzhou Normal UniversityXinzhou 034000China Department of Biological Sciences Xinzhou Normal UniversityXinzhou 034000China

Climate warming profoundly affects plant biodiversity, community productivity, and soil properties in alpine and subalpine grassland ecosystems. However, these effects are poorly understood across elevational gradients in subalpine meadow ecosystems. To reveal the elevational patterns of warming effects on plant biodiversity, community structure, productivity, and soil properties, we conducted a warming experiment using open-top chambers from August 2019 to August 2022 at high(2764 m a. s. l.), medium(2631 m a. s. l.), and low(2544 m a. s. l.) elevational gradients on a subalpine meadow slope of Mount Wutai, Northern China. Our results showed that three years of warming significantly increased topsoil temperature but significantly decreased topsoil moisture at all elevations(P<0.05), and the percentage of increasing temperature and decreasing moisture both gradually raised with elevation lifting. Warming-induced decreasing proportions of soil organic carbon(SOC, by 19.24%), and total nitrogen(TN, by 24.56%) were the greatest at high elevational gradients. Experimental warming did not affect topsoil C: N, p H, NO_(3)^(-)-N, or NH_(4)^(+)-N at the three elevational gradients. Warming significantly increased species richness(P<0.01) and Shannon-Weiner index(P<0.05) at low elevational gradients but significantly decreased belowground biomass(P<0.05) at a depth of 0–10 cm at three elevational gradients. Warming caused significant increases in the aboveground biomass in the three elevational plots. Warming significantly increased the aboveground biomass of graminoids in medium(by 92.47%) and low(by 98.25%) elevational gradients, that of sedges in high(by 72.44%) and medium(by 57.16%) elevational plots, and that of forbs in high(by 75.88%), medium(by 34.38%), and low(by 74.95%) elevational plots. Species richness had significant linear correlations with SOC, TN, and C: N(P<0.05), but significant nonlinear responses to soil temperature and soil moisture in the warmed treatment(P<0.05). The warmed aboveground biomass had

关键词： Warming effect Plant diversity pattern Community structure change Elevation gradient alpine meadow ecosystem Mount Wutai

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Impact of Cloud on Net ecosystem CO2 Exchange of alpine meadow in Tibetan Plateau

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Chinese Journal of Population,Resources and Environment 2010年第4期8卷 69-75页

作者： Fan Yuzhi Zhang Xianzhou Shi Peili Wu Jianshuang Institute of Geographic Sciences and Resources Research Chinese Academy of Sciences Beijing 100101 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Meteorological elements and CO2 fluxes over alpine meadow ecosystem were observed continuously from 2004 to 2005 in Damxung alpine meadow Flux Station, China Flux Network. Based on the eddy covariance CO2 fluxes and meteorological data obtained, the relationships among the CO2 fluxes, the cloud amount, and the meteorological factors in alpine meadow ecosystem were explored and analyzed. Some conclusions can be drawn from the discussion with previous researches as following: (1) the cloud amount can affect the net ecosystem CO2 exchange (NEE) of alpine meadow on Tibetan Plateau; (2) the soil temperature sensitive to the cloud amount, is a major environmental controlling factor for NEE, and closely relates to the maximum of NEE. In the morning period with large cloud amount, the NEE reaches its maximum when the clearness index ranges from 0.5 to 0.7; yet in the afternoon it comes to the maximum with the index from 0.2 to 0.35. The span of soil temperature covers from 12 to 15°C as the NEE at its highest; (3) the scatterplots between NEE and photosynthetic available radiation (PAR) was a significant inverse triangle in the clear day, two different kinds of concave curves in the cloudy day, and strongly convergent rectangular hyperbola in the overcast day. These differences were controlled by the changes of light radiation and soil temperature. © 2010 Taylor & Francis Group, LLC.

关键词： alpine meadow ecosystem Clearness index Cloud amount Net ecosystem CO2 exchange Tibetan Plateau

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Modelling of Energy Flow,Rotational Grazing and Potential Productivity in an alpine meadow Grazing ecosystem

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Tsinghua Science and Technology 2000年第4期5卷 446-456页

作者：黄大明 Christiane Willeke-Wetstein Joerg Steinbach Department of Biological Sciences and Biotechnology Tsinghua UniversityBeijing 100084China Institute of Animal Breeding&Genetics Department of Livestock EcologyJustus-Liebig-University GiessenLudwigstr asse 21D-35390 GiessenGermany

An eight-compartment model of the energy dynamics of an alpine meadow-sheep grazing ecosystem was proposed based on SHIYOMI's system approach. The compartments were the above-ground plant portion, the underground live portion including roots, the underground dead portion including roots, the above-ground litter Ⅰ (degradable portion), the above-ground litter Ⅱ (undegradable portion), the sheep intake, the sheep liveweight, and the faeces. Energy flows between the eight compartments were described by eight simultaneous differential equations. All parameters in the model were determined from paddock experiments. The model was designed to provide a practical method for estimating the effects of the number of rotational grazing subplots, grazing period, and grazing pressure on the performance of grazing systems for perennial alpine meadow pasture. The model provides at least 28 different attributes for characterizing the performance of the grazing system. Analyses of 270 simulated rotational grazing systems of summer-autumn meadow pasture (grazing from 1st June to 30 October each year) provided an inference base to support two recommendations concerning management variables. First, with a three-paddock, 29-day grazing period and 30.14kJ·m -2 ·day -1 grazing pressure scheme, the system has the highest total grazing intake, 4250.44kJ·m -2 , during the grazing season. Secondly, with a three-paddock, 7-day grazing period and 28.89kJ·m -2 ·day -1 grazing pressure scheme, the accumulated graze is 4073.34kJ·m -2 . The potential productivity of the alpine meadow under grazing is defined in this paper as the maximal dry biomass of herbage grazed by the grazing animals over the whole growing season. It has been analysed by applying optimal control theory to the model. The productivity is regarded as the objective function to be maximized through optimization of the time course of the grazing pressure, the control variable. The results show that: (1) under constant grazing pressure,

关键词： alpine meadow ecosystem compartment model energy flow modelling potential productivity rotation graz?

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Advances in Research of alpine meadow ecosystem

Advances in Research of Alpine Meadow Ecosystem

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作者： Zhao Xinquan and Zhou Xingmin Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining 810001, P.R. China

＜正＞The Tibet plateau, a unique geographic unit, has a great impact on the Eurasia atmospheric circulation and distribution of various ecosystems and their structure, function, adaptation, and evolution pattern since the plateau formed as the highest plateau of the world. The frosty, alpine shrub, alpine meadow, alpine steppe and alpine desert ecosystem are widely distributed in the area, which covers 2.5 million km2, alpine shrub and meadow cover about 35% of this land area. Due to the high altitude climate, the ecosystem is fragile and sensitive to global climate changes. Therefore, the area is an ideal place to study the response of ecosystem to climate changes. On the other hand, grassland degradation, a main form of land desertification, has been described as a process of retrogressive succession of grassland ecosystem resulting from human activity （such as over grazing） and unfavorable environmental condition on the Tibet plateau. Overgrazing has led to degradation of 30% the pasturelands in Haibei region. In order to understand the structural and functional aspects of the alpine ecosystem and to promote sustainable animal production system, the Haibei alpine meadow Research Station was established in 1976. A series of intensive studies on ecosystem structure and function, including the energy flow and nutrient cycling of the ecosystem, were the main task in the first 10 years. Meanwhile, studies with 5 different grazing intensities on both summer and winter pasture had been conducted. In the early of the 1990s, the research station started to focus research work on global warming, biodiversity and sustainable animal production system in pastoral area. Various ways to improve degraded pasturelands have been developed in the region.

关键词： alpine meadow ecosystem Haibei station research advance

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Effects of warming and clipping on plant and soil properties of an alpine meadow in the Qinghai-Tibetan Plateau, China

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Journal of Arid Land 2015年第2期7卷 189-204页

作者： Man Hou XU Fei PENG Quan Gang YOU Jian GUO Xia Fei TIAN Min LIU Xian XUE Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Taiyuan Normal University

Climate warming and livestock grazing are known to have great influences on alpine ecosystems like those of the Qinghai-Tibetan Plateau （QTP） in China. However, it is lacking of studies on the effects of warming and grazing on plant and soil properties in these alpine ecosystems. In this study, we reported the related research from manipulative experiment in 2010-2012 in the QTP. The aim of this study was to investigate the individual and combined effects of warming and clipping on plant and soil properties in the alpine meadow ecosystem. Infrared radiators were used to simulate climate warming starting in July 2010, while clipping was performed once in Octo- ber 2011 to simulate the local livestock grazing. The experiment was designed as a randomized block consisting of five replications and four treatments： control （CK）, warming （W）, clipping （C） and warming＋clipping combination （WC）. The plant and soil properties were investigated in the growing season of the alpine meadow in 2012. The results showed that W and WC treatments significantly decreased relative humidity at 20-cm height above ground as well as significantly increases air temperature at the same height, surface temperature, and soil temperature at the depth of 0-30 cm. However, the C treatment did not significantly decrease soil moisture and soil temperature at the depth of 0-60 cm. Relative to CK, vegetation height and species number increased significantly in W and WC treatment, respectively, while vegetation aboveground biomass decreased significantly in C treatment in the early growing season. However, vegetation cover, species diversity, belowground biomass and soil properties at the depth of 0-30 cm did not differ significantly in W, C and WC treatments. Soil moisture increased at the depth of 40-100 cm in W and WC treatments, while belowground biomass, soil activated carbon, organic carbon and total nitrogen increased in the 30-50 cm soil layer in W, C and WC treatments. Although the initial responses of plant and soil properties to experimen

关键词： simulated warming overgrazing soil property plant property alpine meadow ecosystem Qinghai-Tibetan Plateau

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