Quantifying the effects of overgrazing on mountainous watershed vegetation dynamics under a changing climate

Hao, Lu; Pan, Cen; Fang, Di; Zhang, Xiaoyu; Zhou, Decheng; Liu, Peilong; Liu, Yongqiang; Sun, Ge

doi:10.1016/j.scitotenv.2018.05.224

Cited by 65 publications

(24 citation statements)

References 50 publications

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“…Climate change and human activities have altered global hydrological cycles (Christensen and Lettenmaier 2007;Brooks 2009;Cuo et al 2009;Xu et al 2016;Li et al 2017;Yang et al 2017;Hao et al 2018a) including the evapotranspiration (ET) processes (Zalewski 2000;Xu et al 2015), resulting in a series of environmental and socioeconomic impacts such as deterioration of water quality, increased runoff, and risk of floods (Roderick and Farquhar 2002;Grant et al 2012;Hallegatte et al 2013;Gao 2016;Gao and Sang 2017). ET is a key component of ecosystem water and energy balances (Hao et al 2015a;Liu et al 2017), and ET is also tightly coupled with the carbon cycle (Sun et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Climatic Controls on Watershed Reference Evapotranspiration Varied during 1961–2012 in Southern China

Qin

Hao

Sun

et al. 2018

J American Water Resour Assoc

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Reference evapotranspiration (ETo) is an important hydrometeorological term widely used in understanding and projecting the hydrological effects of future climate and land use change. We conducted a case study in the Qinhuai River Basin that is dominated by a humid subtropical climate and mixed land uses in southern China. Long‐term (1961–2012) meteorological data were used to estimate ETo by the FAO‐56 Penman–Monteith model. The individual contribution from each meteorological variable to the trend of ETo was quantified. We found basin‐wide annual ETo decreased significantly (p < 0.05) by 3.82 mm/yr during 1961–1987, due to decreased wind speed, solar radiation, vapor pressure deficit (VPD), and increased relative humidity (RH). However, due to the increased VPD and decreased RH, the ETo increased significantly (p < 0.05) in spring, autumn, and annually at a rate of 2.55, 0.56, and 3.16 mm/yr during 1988–2012, respectively. The aerodynamic term was a dominant factor controlling ETo variation in both two periods. We concluded the key climatic controls on ETo have shifted as a result of global climate change during 1961–2012. The atmospheric demand, instead of air temperature alone, was a major control on ETo. Models for accurately predicting ETo and hydrological change under a changing climate must include VPD in the study region. The shifts of climatic control on the hydrological cycles should be considered in future water resource management in humid regions.

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Section: Introductionmentioning

confidence: 99%

Climatic Controls on Watershed Reference Evapotranspiration Varied during 1961–2012 in Southern China

Qin

Hao

Sun

et al. 2018

J American Water Resour Assoc

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“…On the other hand, policy implementation is hard to control. The boundaries of paid rotation to grazing in pastoral areas since 1990 were not clear, despite the fact that in some areas grazing has been banned, but because of the impact of the grazing bans on the economy, illegal or informal grazing remained out of control and can damage restored pastures (Hao et al, 2018). In addition, multilinear regression analysis shows that contribution of precipitation, temperature, and vegetation cover ( M ) to streamflow changes were 67.94%, 5.33%, and −2.7%, respectively (Figure S6).…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, increasing water yield from Upper Hei River Basin (UHRB) is the fundamental method that can ensure development and maintain ecological stability of the midstream and downstream simultaneously for the whole river basin. The UHRB have implemented a series of ecological rehabilitation initiatives since 1980s, including returning grazing land to grassland and forest protection in water source areas to protect ecosystem and conserve water (Cheng et al, 2014; Hao et al, 2018). Land use/cover changed dramatically under the background of ecological rehabilitation, but at the same time the sensitivity of UHRB to climate change intensifies the uncertainty of water yield (Chen, Li, et al, 2015; Guo et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Rational Planning of Land Use Can Maintain Water Yield Without Damaging Ecological Stability in Upstream of Inland River: Case Study in the Hei River Basin of China

Zhang

et al. 2020

JGR Atmospheres

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Upstream inland rivers provide most of water resources for midstream and downstream in arid and semiarid regions. From the perspective of ecological rehabilitation, it is necessary to simultaneously ensure upstream streamflow while still maintaining economy-ecosystem balance in upstream. However, vegetation dynamics effects caused by ecological rehabilitation cannot be well evaluated in previous studies due to the sparseness of observations at regional scales. With increased availability of vegetation and hydrological data, it is now possible to explore the relationship between water yield and ecological balance affected by vegetation dynamics. This study takes Upper Hei River Basin, part of the Asia's water tower-the Qinghai-Tibet Plateau, as an example and uses the Eagleson's ecohydrological model to explore the effects of vegetation dynamics on streamflow and ecology in growing seasons during 1992-2015. We compare scenarios with and without vegetation changes and find that there is limited evidence that ecological rehabilitation could enhance water yield. Approximately 51.31% of Upper Hei River Basin vegetation cover (M) tends to deviate from ecological optimization state compared to equilibrium vegetation cover (M eq). In order to explore ways to ensure streamflow and maintain ecology, different vegetation scenarios are simulated. Results show that on average, grazing in area where M is larger than M eq could increase streamflow by approximately 7.3%/year and planting trees in other area could increase streamflow by approximately 2.9%/year. Therefore, effective control on vegetation dynamics can simultaneously ensure streamflow and maintain ecological balance, which can also provide guidance and theoretical support for upstream inland river planning.

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“…An important application of the LI and LAI values in pasture management is what is called, residual LAI, which is the total amount of photosynthetic active tissues left after grass harvesting by grazing or cutting. Adequate residual LAI is extremely important to avoid situations such as overgrazing (Hao et al, 2018). LI and LAI can be measured through direct and indirect methodologies (Jonckheere et al, 2004;Casa et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Correlations between plant height and light interception in grasses by different light meter devices

Coêlho

Santos

Cunha

et al. 2020

Agraria

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This study tested if the type of light meter device can influence the relationships between plant canopy height with light interception (LI) and leaf area index (LAI), in different types of warm-season grasses. LI and LAI were measured using Digital Plant Canopy Imager model 120 (CI-120) (CID Bio-science ®) and Plant Canopy Analyzer LAI-2000 (LI-COR ®). Seven warm-season grasses were evaluated Urochloa decumbens (

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Quantifying the effects of overgrazing on mountainous watershed vegetation dynamics under a changing climate

Cited by 65 publications

References 50 publications

Climatic Controls on Watershed Reference Evapotranspiration Varied during 1961–2012 in Southern China

Climatic Controls on Watershed Reference Evapotranspiration Varied during 1961–2012 in Southern China

Rational Planning of Land Use Can Maintain Water Yield Without Damaging Ecological Stability in Upstream of Inland River: Case Study in the Hei River Basin of China

Correlations between plant height and light interception in grasses by different light meter devices

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