Regional erosion risk mapping for decision support: A case study from West Africa

The rapid process of urbanization, accompanied by the sharp increase of urban population and expansion of artificial surface, has resulted in the loss of natural ecosystems and the degradation of ecosystem services. Identifying and protecting key places that have high importance for ecological sustainability are great challenges. Ecological security patterns are such an integrated approach to protecting regional ecological sustainability. In this study, taking Yunnan Province, China as a case study area, ecological sources were identified through ecosystem services, and circuit theory was used to model ecosystem processes in heterogeneous landscapes via calculating the 'resistance' or 'current', and thus to identify ecological corridors and key ecological nodes. The results showed that, ecological security patterns included 66 ecological sources, 186 ecological corridors, 24 pinch-points and 10 barriers. In details, the ecological sources were mainly distributed in the southwest and northwest of Yunnan Province, with the ecological corridors locating along the high mountains, and both ecological sources and corridors were mostly covered with forest land. Pinch-points covered by forest land and cultivated land, were distributed in the middle of Yunnan Province along the rivers. Approximately 75.9% nature reserves were located in the identified ecological sources, and the remainings were mainly distributed in eastern Yunnan Province with small area, showing the effectiveness in identifying ecological security patterns. Among 81 projects of low-slope hill development carried out in Yunnan Province, 46.9% showed potential human stress on regional ecological security. Based on ecosystem services and circuit theory, this study provides a new approach to identifying the spatial range of ecological corridors and the specific location of key nodes for effective ecological conservation and restoration.

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“…Specifically, soil conservation service was quantified using the Revised Universal Soil Loss Equation (Wischmeir, 1965;Okou et al, 2016).…”

Section: Ecological Sourcesmentioning

confidence: 99%

Linking ecosystem services and circuit theory to identify ecological security patterns

Peng

Yang

Liu

et al. 2018

Science of The Total Environment

491

227

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“…The β of nitrogen or phosphorus are 1.35 and 1.28, respectively, according to the previous literature [48]. Different scholars have assessed soil erosion in a variety of ways, by using the Instituto Nacional para la Conservación de la Naturaleza (ICONA) model [49] and RUSLE model [50][51][52]. Sediment dynamics at the catchment scale depend primarily on climate (especially the rain intensity), soil, and vegetation characteristics, and factitious factors such as agricultural activities or dam construction and operation [53].…”

Section: Export Coefficient Modelmentioning

confidence: 99%

Temporal and Spatial Changes of Non-Point Source N and P and Its Decoupling from Agricultural Development in Water Source Area of Middle Route of the South-to-North Water Diversion Project

et al. 2019

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The quantitative estimation of non-point source (NPS) pollution provides the scientific basis for sustainability in ecologically sensitive regions. This study combined the export coefficient model and Revised Universal Soil Loss Equation to estimate the NPS nitrogen (NPS-N) and NPS phosphorus (NPS-P) loads and then evaluated their relationship with Primary Industrial Output Value (PIOV) in the water source area of the middle route of South-to-North Water Diversion Project (SNWDP) for 2000-2015. The estimated results show that: (1) dissolved nitrogen (DN) load increased 0.55%, and dissolved phosphorus (DP) load decreased 4.60% during the 15 years. Annual loads of adsorbed nitrogen (AN) and adsorbed phosphorus (AP) increased significantly before 2005 and then decreased after 2005. Compared with 2000, AN and AP loads in 2015 significantly decreased by 32.72% and 30.81%, respectively. Hanzhong Basin and Ankang Basin are key areas for controlling dissolved pollution, and southern and northern regions are key areas for adsorbed pollution. (2) From 2000 to 2005, NPS pollutants and PIOV showed weak decoupling status. By 2015, NPS pollutants had strong decoupling from PIOV in most counties. (3) Land use has been the main source of NPS-N and NPS-P pollution, accounting for about 75% of NPS-N and 50% of NPS-P based on the average value over the study period. In the future, various measures-such as returning cropland to forest and reducing the number of livestock-could be adopted to reduce the risk of NPS pollution. NPS pollution caused by livestock was grown over the past 15 years and had not yet been effectively controlled, which still needs to be urgently addressed. Collecting ground monitoring data and revising parameters are effective means to improve the accuracy of simulation, which deserve further study. The results will also provide scientific support for sustainable development in similar regions.Sustainability 2019, 11, 895 2 of 23 causes of water pollution [3]. Due to the attention received by the community, point source pollution has, for the most part, been effectively curbed, and NPS pollution has gradually become the dominant contributor to water pollution. Non-point source pollution has always been an important factor affecting water quality in the United States [4]. To solve the problem, since 1990, the United States government has invested over $100 million annually on average to solve the problem [5]. In Miksa City, Japan, 61.5% of the nitrogen load comes from non-point source pollution caused by high-intensity agricultural activities [6]. According to the First National Pollution Census Bulletin, NPS nitrogen and phosphorus loads from Chinese agricultural sources in watersheds account for 57.19% and 67.27% of total nitrogen and total phosphorus pollution, respectively [7,8]. Non-point source nitrogen and phosphorus lead to eutrophication and the decrease in dissolved oxygen in surface water, which not only damages the aquatic environment and the balance of the ecosystem, but also seriously affects the qu...

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“…Prior to the calibration of parameters to which the model output is most sensitive the corresponding initial values were identified based on previous studies that used SHETRAN and based on sensitivity analyses. The sensitivity analyses were done based on the "one factor at a time" (OFAT) method using Equation (6) [72]:…”

Section: Model Sensitivity Calibration and Validationmentioning

confidence: 99%

“…On the other hand, socio-economic factors contribute to the problem and are often responsible for the severity of soil erosion. Among those factors, increased pressure on land resources through population growth is highlighted as a major reason for accelerated soil erosion [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Applying SHETRAN in a Tropical West African Catchment (Dano, Burkina Faso)—Calibration, Validation, Uncertainty Assessment

Hipt

Diekkrüger

Steup

et al. 2017

Water

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This study presents the calibration and validation of the physically based spatially distributed hydrological and soil erosion model SHETRAN for the Dano catchment, Burkina Faso. A sensitivity analysis of six model parameters was performed to assess the model response and to reduce the number of parameters for calibration. The hydrological component was calibrated and validated using observed discharge data of two years. Statistical quality measures (R 2 , NSE, KGE) ranged from 0.79 to 0.66 during calibration and validation. The calibrated hydrological component was used to feed the erosion modeling. The simulated suspended sediment load (SSL) was compared with turbidity-based measurements of SSL of two years. Achieved quality measures are comparable to other SHETRAN studies. Uncertainties of measured discharge and suspended sediment concentration were determined to assess the propagated uncertainty of SSL. The comparison of measurement uncertainties of discharge and SSL with parameter uncertainty of the corresponding model output showed that simulated discharge and SSL were frequently outside the large measured uncertainty bands. A modified NSE was used to incorporate measurement and parameter uncertainty into the efficiency evaluation of the model. The analyses of simulated erosion sources and spatial patterns showed the importance of river erosion contributing more than 60% to the total simulated sediment loss.

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Regional erosion risk mapping for decision support: A case study from West Africa

Cited by 36 publications

References 38 publications

Linking ecosystem services and circuit theory to identify ecological security patterns

Linking ecosystem services and circuit theory to identify ecological security patterns

Temporal and Spatial Changes of Non-Point Source N and P and Its Decoupling from Agricultural Development in Water Source Area of Middle Route of the South-to-North Water Diversion Project

Applying SHETRAN in a Tropical West African Catchment (Dano, Burkina Faso)—Calibration, Validation, Uncertainty Assessment

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