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Journal ArticleDOI: 10.1080/02723646.2020.1735859

Can ecological restoration improve soil properties and plant growth in valley-slope sand dunes on southern Tibetan Plateau?

04 Mar 2021-Physical Geography (Taylor & Francis)-Vol. 42, Iss: 2, pp 143-159
Abstract: Global warming poses a serious threat to the alpine grassland on the Tibetan Plateau. Ecological restoration is an effective measure for adapting to climate change and controlling desertification. ...

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Topics: Desertification (59%), Plateau (58%), Restoration ecology (58%) ... show more

5 results found

Journal ArticleDOI: 10.1111/GCB.15361
Yanfu Bai1, Lina Ma1, A. A. Degen2, Muhammad Khalid Rafiq3  +11 moreInstitutions (7)
Abstract: Soil nutrient contents and organic carbon (C) stability are key indicators for restoration of degraded grassland. However, the effects of long-term active restoration of extremely degraded grassland on soil parameters have been equivocal. The aims of this study were to evaluate the impact of active restoration of degraded alpine grassland on: (a) soil organic matter (SOM) mineralization; and (b) the importance of biotic factors for temperature sensitivity (Q(10)) of SOM mineralization. Soils were sampled from intact, degraded and restored alpine grasslands at altitudes ranging between 3,900 and 4,200 m on the Tibetan Plateau. The samples were incubated at 5, 15 and 25 degrees C, andQ(10)values of SOM mineralization were determined. Structural equation modeling was used to evaluate the importance of vegetation, soil physico-chemical properties and microbial parameters forQ(10)regulation. TheQ(10)of N mineralization was similar among intact, degraded and restored soils (0.84-1.24) and was higher in topsoil (1.09) than in subsoil (0.92). The best predictive factor of CO2-Q(10)for intact grassland was microbial biomass, for degraded grassland was basal microbial respiration, and for restored grassland was soil bulk density. Restoration by planting vegetation decreased theQ(10)of SOM mineralization as soil bulk density, the most important negative predictor, increased in restored grassland. TheQ(10)of SOM mineralization in topsoil was 14% higher than in subsoil because of higher microbial abundance and exo-enzyme activities. The NH(4)(+)content was greatest in intact soil, while NO(3)(-)content was greatest in degraded soil. The SOM mineralization rate decreased with grassland degradation and increased after long-term (>10 years) restoration. In conclusion, extremely degraded grassland needs proper long-term management in active restoration projects, especially for improvement of soil nutrients in a harsh environment.

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Topics: Soil organic matter (61%), Grassland degradation (61%), Mineralization (soil science) (58%) ... show more

8 Citations

Open accessJournal ArticleDOI: 10.3390/SU13105732
20 May 2021-Sustainability
Abstract: Jiuquan City is a typical ecologically fragile area in the arid areas of Northwest China, and unreasonable human activities directly affect the regional ecological security. Scientifically, it is necessary to construct an ecological landscape pattern on the basis of ecological security evaluation. This paper selected evaluation factors based on the perspective of “environmental base and human interference”, used spatial principal component analysis (SPCA) to comprehensively evaluate the regional landscape ecological security, and used the minimum cumulative resistance (MCR) model to construct the regional ecological security pattern. The results show that the overall ecological security level of the study area is low, and the area with a moderate safety level and below is 122,100 km2, accounting for 72.57% of the total area of the study area. The total area of the identified ecological source area is 6683 km2, the spatial distribution is extremely uneven, and it is extremely concentrated in the southern region; 32 ecological corridors with a total length of 3817.8 km are identified, of which corridor NO. 1–4 run through the Qilian Mountains, 11 oasis areas, and 14 nature reserves. The length of ecological corridors is 1376.1 km, accounting for 36.04% of the total. Forty-two ecological nodes are identified, and the central corridor area is more distributed; four ecological restoration zones are divided, including an ecological conservation zone, ecological improvement zone, ecological control zone, and ecological restoration zone, with areas of 34,380.3 km2, 61,884.4 km2, 21,134.4 km2, and 50,648.3 km2, respectively. Through the delineation of the urban ecological network pattern composed of source areas, corridors, and nodes, as well as the delineation of ecological restoration zones, the ecological security level of the study area will be effectively improved. Furthermore, a new method of ecological restoration zoning will be used, hoping to provide a useful reference for improving the quality of the ecological environment in arid areas and optimizing the spatial pattern of the land.

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3 Citations

Journal ArticleDOI: 10.1016/J.JCLEPRO.2021.129156
Hongqiong Guo1, Qiang Yu1, Yanru Pei1, Ge Wang1  +1 moreInstitutions (1)
Abstract: Carbon neutrality is a long-term climate goal in the context of global warming and can be achieved by reducing carbon emissions and increasing carbon sinks. Vegetation has a very important and irreplaceable role in increasing carbon sinks, but it is often destroyed, especially in desertification and mining areas. Therefore, restoration of the vegetation in these areas is essential. Seeking the optimal solution for landscape spatial structure through adjustment and optimization can promote ecological processes, improve environment and soil conditions on a large scale, provide favorable conditions for vegetation growth, and is an effective way to achieve vegetation restoration to increase carbon sinks. Here, a targeted landscape spatial structure optimization scheme called EFCT model was developed for complex ecological situation of Ordos, with the goal of increasing carbon sinks to achieve carbon neutrality. The scheme identified areas where the landscape spatial structure needs to be optimized and the direction of optimization based on the differences in the synergy degree between ecological function and connectivity of the patches. The study also compared the carbon sink function and robustness of the landscape spatial structure before and after optimization according to the scheme. The results show that the patches in the landscape spatial structure of Ordos form four separate clusters distributed in a differentiated east-west part of the structure, with higher ecological function and poorer connectivity in the east and the opposite in the west. In the landscape spatial structure optimized by the EFCT model, the ecological function of 42 patches was enhanced, and 19 patches and 44 corridors were added. The total carbon sink in the optimized structure increased by 31.51% compared to the unoptimized structure, mainly due to the improved ecological function of the grassland patches in the western structure, in addition to the carbon sink contribution of the new patches and corridors. At the same time, the connectivity between the four clusters had been enhanced and the structure was more coherent and stable.

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Topics: Carbon neutrality (54%), Vegetation (53%), Carbon sink (51%)

Journal ArticleDOI: 10.1080/02723646.2021.1961361
Turgay Dindaroglu1, Vesna Tunguz2, Emre Babur1, Oleksandr Menshov3  +1 moreInstitutions (4)
04 Aug 2021-Physical Geography
Abstract: Topography is a key factor that affects edaphic, climatic, and biotic factors directly or indirectly. Relationships between Compound Topographic Index (CTI) model and soil properties were investiga...

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Topics: Edaphic (56%), Soil ecology (50%)

33 results found

Open accessJournal ArticleDOI: 10.1111/J.1466-8238.2007.00357.X
Takafumi Ohsawa1, Yuji Ide1Institutions (1)
Abstract: Aim To understand global patterns of genetic variation in plant species on mountains and to consider the significance of mountains for the genetic structure and evolution of plant species. Location Global. Methods We review published studies. Results Genetic diversity within populations can vary along altitudinal gradients in one of four patterns. Eleven of 42 cited studies (26% of the total) found that populations at intermediate altitudes have greater diversity than populations at lower and higher altitudes. This is because the geographically central populations are under optimal environmental conditions, whereas the peripheral populations are in suboptimal situations. The second pattern, indicating that higher populations have less diversity than lower populations, was found in eight studies (19%). The third pattern, indicating that lower populations have lower diversity than higher populations, was found in 10 studies (24%). In 12 studies (29%), the intrapopulation genetic variation was found to be unaffected by altitude. Evidence of altitudinal differentiation was found in more than half of these studies, based on measurements of a range of variables including genome size, number of chromosomes or a range of loci using molecular markers. Furthermore, great variation has been found in phenotypes among populations at different altitudes in situ and in common garden experiments, even in cases where there was no associated variation in molecular composition. Mountains can be genetic barriers for species that are distributed at low elevations, but they can also provide pathways for species that occupy high-elevation habitats. [Correction added after publication 9 October 2007: ‘less diversity’ changed to ‘greater diversity’ in the second sentence of the Results section of the Abstract]. Main conclusions Genetic diversity within populations can vary along altitudinal gradients as a result of several factors. The results highlight the importance of phenotypic examinations in detecting altitudinal differences. The influence of mountain ridges on genetic differentiation varies depending, inter alia , on the elevation at which the species occurs. Based on these findings, zoning by altitudes or ridges would be helpful for the conservation of tree populations with the onset of global warming.

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Topics: Genetic diversity (56%), Range (biology) (55%), Genetic variability (54%) ... show more

202 Citations

Open accessJournal ArticleDOI: 10.2136/SSSAJ2007.0201
Abstract: Erosion and loss of organic carbon (OC) result in degradation of the soil surface. Rill and interrill erosion processes on a silt loam soil were examined in laboratory rainfall and flume experiments. These experiments showed that rill and interrill erosion processes have contrasting impacts on enrichment of OC in transported sediment. Rill erosion was found to be nonselective, while for interrill erosion the enrichment ratio of OC, ER OC , varied between 0.9 and 2.6 and was inversely related to the unit sediment discharge. At unit sediment discharge values >0.0017 kg s -1 m -1 , the ER OC remained equal to 1. The enrichment process was not influenced by raindrop impact. Enrichment of OC by "aggregate stripping" was found to be unimportant in our study. This was attributed to the low aggregate stability of the soil and the equal distribution of OC within the different soil aggregate classes.

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Topics: Erosion (56%), Sediment (54%), Rill (53%) ... show more

124 Citations

Journal ArticleDOI: 10.1016/J.CATENA.2016.09.005
Qing Li1, Chunlai Zhang1, Yaping Shen1, Wenru Jia1  +1 moreInstitutions (1)
01 Dec 2016-Catena
Abstract: Accurately identifying the contributions of climate change and human activities to desertification will support effective strategies for combating desertification. In this study, we employed the changes in net primary productivity (NPP) in areas of aeolian desertification on the Qinghai-Tibet Plateau from 2000 to 2014 to determine the dynamics of desertification. Changes in the potential NPP (PNPP) and the difference between PNPP and actual NPP (ANPP) revealed the relative contributions of climate change and human activities to desertification. We found overall mitigation of desertification during the study period. However, desertification varied both spatially and temporally. Areas with mitigation accounted for 80.1% of the total desertified land; other areas experienced exacerbation. In 67.3% of the area of mitigation, the improvement was attributed to climate change, and especially to increased precipitation. Climate change also accounted for the exacerbation of desertification in 38.0% of the total area in which desertification worsened, largely due to reduced precipitation. Therefore, climate change was the dominant factor for mitigation of desertification, and human activities were the dominant factor for exacerbation of desertification. The dominant factors for mitigation and exacerbation varied spatially. In the central and northeastern Qinghai-Tibet Plateau, climate change was the primary factor for mitigation of desertification and human activities dominated the exacerbation of desertification. In the southern and western Qinghai-Tibet Plateau, the reverse was the case. The ecological protection projects that have been implemented since 2000 in most of the Qinghai-Tibet Plateau have not yet become a dominant factor in controlling desertification processes.

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Topics: Desertification (66%), Climate change (52%)

84 Citations

Journal ArticleDOI: 10.1016/J.ECOLIND.2014.09.024
Shezhou Luo1, Shezhou Luo2, Cheng Wang1, Feifei Pan3  +4 moreInstitutions (4)
Abstract: A B S T R A C T Wetland vegetation is a core component of wetland ecosystems. Wetland vegetation structural parameters, such as height and leaf area index (LAI) are important variables required by earth-system and ecosystem models. Therefore, rapid, accurate, objective and quantitative estimations of wetland vegetation structural parameters are essential. The airborne laser scanning (also called LiDAR) is an active remote sensing technology and can provide accurate vertical vegetation structural parameters, but its accuracy is limited by short, dense vegetation canopies that are typical of wetland environments. The objective of this research is to explore the potential of estimating height and LAI for short wetland vegetation using airborne discrete-return LiDAR data. The accuracies of raw laser points and LiDAR-derived digital elevation models (DEM) data were assessed using field GPS measured ground elevations. The results demonstrated very high accuracy of 0.09 m in raw laser points and the root mean squared error (RMSE) of the LiDAR-derived DEM was 0.15 m. Vegetation canopy height was estimated from LiDAR data using a canopy height model (CHM) and regression analysis between field-measured vegetation heights and the standard deviation (s) of detrended LiDAR heights. The results showed that the actual height of short wetland vegetation could not be accurately estimated using the raster CHM vegetation height. However, a strong relationship was observed between the s and the field-measured height of short wetland vegetation and the highest correlation occurred (R 2 = 0.85, RMSE = 0.14 m) when sample radius was 1.50 m. The accuracy assessment of the best-constructed vegetation height prediction model was conducted using 25 samples that were not used in the regression analysis and the results indicated that the model was reliable and accurate (R 2 = 0.84, RMSE = 0.14 m). Wetland vegetation LAI was estimated using laser penetration index (LPI) and LiDAR-predicted vegetation height. The results showed that the vegetation height-based predictive model (R 2 = 0.79) was more accurate than the LPI-based model (the highest R 2 was 0.70). Moreover, the LAI predictive model based on vegetation height was validated using the leave-one-out cross-validation method and the results showed that the LAI predictive model had a good generalization capability. Overall, the results from this study indicate that LiDAR has a great potential to estimate plant height and LAI for short wetland vegetation. a 2014 Published by Elsevier Ltd.

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Topics: Enhanced vegetation index (68%), Vegetation (pathology) (62%), Leaf area index (53%) ... show more

69 Citations

Journal ArticleDOI: 10.1016/J.FORECO.2008.10.021
Abstract: The altitudinal pattern of genetic variation in Pinus hartwegii Lindl. populations was explored for seedling height growth, frost damage, grass-stage, and phenological stage of the terminal shoot. A provenance test was conducted with open-pollinated seed from 13 populations collected along an altitudinal transect (3000–3600 m) at the National Park Pico de Tancitaro, Michoacan, center-west Mexico. Height growth of seedlings in a nursery was assessed at seven and 18 months of age. Frost damage at −15 °C was evaluated in laboratory at 18 months of age; proportion of plants that had left grass-stage and stage of shoot development was assessed at the age of 22 months. Significant differences among provenances (P

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Topics: Pinus hartwegii (57%), Frost (51%), Population (50%)

55 Citations