Resilience of revegetated grassland for restoring severely degraded alpine meadows is driven by plant and soil quality along recovery time: A case study from the Three-river Headwater Area of Qinghai-Tibetan Plateau

Gao, Xiaoxia; Dong, Shikui; Xu, Yudan; Wu, Shengnan; Wu, Xiaohui; Zhang, Xi; Liu, Shiliang; Li, Shuai; Liu, Shiliang; Shang, Zhanhuan; Qian, Dong; Zhou, Huakun; Stufkens, Paul

doi:10.1016/j.agee.2019.01.010

Cited by 70 publications

(48 citation statements)

References 63 publications

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“…This grassland has been degraded since the 1980s, thereby reducing its productivity and biodiversity (Chen, Yi, & Qin, 2017; Li, Guo, Jakubowski, & Kelly, 2012) and affecting the regional ecological security (Li et al, 2019). In addition to high ecological inertia (Zhou et al, 2006) and insufficient anti‐interference ability (Gao et al, 2019), human activities, such as overgrazing, and unsuitable reclamation efforts (Li et al, 2016) have become dominant factors resulting in grassland degradation. The ecological restoration and assessment of degraded grasslands in the QTP have been the focus of many researchers (Liu, Zamanian, et al, 2018; Pan, Zou, Liu, Wu, & He, 2017).…”

Section: Introductionmentioning

confidence: 99%

Feasibility of terrestrial laser scanning for quantification of vegetation structure parameters of restored sandy land in the southern Qinghai–Tibeten Plateau

Tian

et al. 2020

Land Degrad Dev

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The efficiency of ecosystem restoration of degraded land is typically assessed using vegetation structure parameters (VSP). However, the field measurement of VSP, particularly in the Qinghai–Tibet Plateau (QTP), which is a problematic area for ecological restoration because of its harsh environment, is generally time‐consuming and labour intensive. Therefore, new methods for VSP measurement should be developed. In this study, VSP were quantified at the individual scale, including their number, height, and crown width. Furthermore, the quadrat scale, such as vegetation coverage (VC) and leaf area index (LAI) on a restored sandy plot (100 m × 100 m) in the middle reaches of the Yarlung Zangbo River basin, is quantified using terrestrial laser scanning. Thereafter, the TLS‐derived VSP are validated by field measurements. To extract the VSP of low‐height vegetation (shrubs) at the individual scale, three approaches are tested: the manual measurement of VSP from TLS data, individual vegetation segmentation (IVS) without specific root locations, and IVS with specific root locations. The results indicate that the VSP of shrubs can be manually derived from the TLS data and are consistent with field measurements. By specifying the root locations before performing the IVS, the identification rate of the number of shrubs can be improved significantly from 40.3% to 100%. The height extracted by the IVS corresponds better with the manual measurement (R2 > 0.99) than with the crown width (R2 < 0.65). At the quadrat scale, the optimal resolution is analyzed to extract the VC. The analysis suggests that the optimal resolution for extracting the VC based on the canopy height model is in the 1‐2 cm range. In extracting the LAI using the voxel‐based method, it is discovered that the appropriate voxel size is linearly dependent on the mean point spacing (y = 2.143x, R2= 0.826). This study provides useful guidance for monitoring the effectiveness of ecological conservation and restoration on the QTP.

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Section: Introductionmentioning

confidence: 99%

Feasibility of terrestrial laser scanning for quantification of vegetation structure parameters of restored sandy land in the southern Qinghai–Tibeten Plateau

Tian

et al. 2020

Land Degrad Dev

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“…Traditionally, the site is used for winter grazing of yak and sheep from December to March. We previously studied grassland degradation processes, soil nutrients and vegetation regeneration at the same site [32,37,38,39].…”

Section: Study Sites and Designmentioning

confidence: 99%

“…Lightly (L), moderately (M) and heavily (H) degraded native grassland, and degraded sown grassland (S) were selected (Additional le 1: Appendix S1). The degraded sown grassland was restored 'bare land' (heavy degraded grassland) more than 10 years ago, but became degraded again with the invasion and spreading of poisonous plants [38,39].…”

Section: Study Sites and Designmentioning

confidence: 99%

Interaction between root exudates and rhizosphere microorganisms facilitates the expansion of poisonous plant species in degraded grassland

Wang

Jia

et al. 2021

Preprint

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Background The interaction between rhizosphere microorganisms and rhizosphere exudates is considered a ‘novel weapon’ for poisonous plants’ colonization, but the relationship between them in facilitating the expansion of poisonous plants in degraded or barren land is poorly understood. We examined this relationship in different degradation levels of alpine grasslands on the Tibetan plateau (3,700 m a.s.l) by determining the composition of root exudates, soil physical and chemical properties, rhizosphere microbial diversity and carbon metabolism of the main poisonous and non-poisonous plant species. Results Soil nutrients, including total organic carbon, total nitrogen and available phosphorous, diversity of microorganisms and microbial carbon metabolism were greater in the rhizosphere of poisonous than in non-poisonous plant species (P < 0.05). The distribution of bacteria and root exudates were plant species specific. Soil microbial communities were affected by habitat and plant species in degraded grassland, and more so for bacteria than fungi. The cell growth and death pathway for the poisonous species Ligularia virgaurea was greater than for other poisonous species (P < 0.05), and the difference increased with an increase in grassland degradation and a decrease in soil nutrients (P < 0.05), which could explain how L. virgaurea became the dominant poisonous species in degraded alpine grassland. The roots of L. virgaurea exudated such compounds as alkaloids, lupinic acid, terpenes, artemisinin, and coumarin, which were correlated positively with different bacteria in different habitats. Conclusion It was concluded that poisonous plant species adapted to degraded grassland through the interaction of root exudates and rhizosphere microorganisms, which facilitated their expansion in degraded alpine grassland.

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“…To combat this environmental disaster, various interventions, such as grazing exclusion, ploughing and weeding, fertilizing, and cultivation have been implemented. Revegetation was proved to be effective in restoring plants and soil nutrients of severely degraded grasslands (Gao et al, 2019; Li et al, 2014). Previous scholars have evaluated the effectiveness of these interventions using species, diversity, vegetation cover, primary productivity, and soil nutrients as indicators (Dong et al, 2010; Dong, Zhao, Wu, Shi, & Ren, 2013; Shang, Ma, Long, & Ding, 2010).…”

Section: Introductionmentioning

confidence: 99%

Plant biomass allocation and driving factors of grassland revegetation in a Qinghai‐Tibetan Plateau chronosequence

Gao

Dong

et al. 2021

Land Degrad Dev

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Biomass allocation is a key factor in understanding how ecosystems respond to changing environmental conditions. The role of soil chemistry in the above‐ and belowground plant biomass allocation in restoring grassland is still incompletely characterized. Consequently, it has led to two competing hypotheses for biomass allocation: optimal partitioning, where the plants allocate biomass preferentially to optimize resource use; and the isometric hypothesis, which postulates that biomass allocation between roots and shoots is fixed. Here we tested these hypotheses over a chronosequence of alpine grasslandsion undergoing restoration in the Qinghai‐Tibetan Plateau, these range from severely degraded to those with 18 years of revegetation with an intact grassland (as a reference). A high proportion of biomass was allocated to the roots in the revegetated grasslands, and more biomass to shoots in the degraded and intact grasslands. The grasslands gradually decreased their root to shoot ratio as revegetation continued, with the lowest value in year 18 of revegetation. Our results showed that aboveground biomass (AGB) was increased by available phosphorus (P), soil moisture, and negatively related to bulk density, while belowground biomass (BGB) was positively impacted by total P and negatively by nitrate nitrogen (N). The trade‐off between them was positively associated with available P and nitrate‐N, and soil nutrient availability is more linked to increased AGB relative to BGB. Our study indicates that biomass allocation is highly variable during the revegetation period from degraded grassland, and is linked with soil properties, thus supporting the optimal partitioning hypothesis.

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Resilience of revegetated grassland for restoring severely degraded alpine meadows is driven by plant and soil quality along recovery time: A case study from the Three-river Headwater Area of Qinghai-Tibetan Plateau

Cited by 70 publications

References 63 publications

Feasibility of terrestrial laser scanning for quantification of vegetation structure parameters of restored sandy land in the southern Qinghai–Tibeten Plateau

Feasibility of terrestrial laser scanning for quantification of vegetation structure parameters of restored sandy land in the southern Qinghai–Tibeten Plateau

Interaction between root exudates and rhizosphere microorganisms facilitates the expansion of poisonous plant species in degraded grassland

Plant biomass allocation and driving factors of grassland revegetation in a Qinghai‐Tibetan Plateau chronosequence

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