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ScienceDirect Metacoupling supply and demand for soil conservation service Wenwu Zhao1,2, Yue Liu1,2, Stefani Daryanto1,2, Bojie Fu1,2, Shuai Wang1,2 and Yanxu Liu1,2 To date most soil conservation service studies heavily focus on measuring soil conservation service supply from the natural system without considering corresponding beneficiaries (i.e. demand), and feedback from the human system. In this paper, we presented an updated soil conservation service assessment framework as a two-way analysis of supply and demand, identifying the impacts of soil conservation on human-wellbeing and the feedback of human activities on soil conservation supply observed at different scales, from local (intracoupling) to regional (telecoupling). Soil conservation services supply can be calculated as the maximum allowable erosion rate minus the current soil erosion rate while soil conservation demand needs consider targets such as the Sustainable Development Goals. Because of the disturbance effect transmutation, ecosystem management may trigger possible unprecedented negative effects on the target processes and/or non-target processes. Tradeoff analysis between soil conservation services and other ecosystems services at multiple scales are therefore necessary for regional sustainable development. Addresses 1 State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China 2 Institute of Land Surface System and Sustainable Development, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China Corresponding author: Fu, Bojie ([email protected])

security [1]. Because erosion also affects the lateral fluxes of soil carbon (C) and soil distribution process, it ultimately affects the global C cycle [2]. Although soil erosion is a natural process, recent evidence has demonstrated that human activities have accelerated global soil erosion rates [3,4]. Soil conservation service, defined as the capacity of ecosystem to prevent soil loss and to store sediment [5,6], is receiving more and more attention, including the modeling and mapping of soil conservation service change, as well as the linking between landscape structure and soil loss process [7,8]. Soil conservation service is often calculated using the Revised Universal Soil Loss Equation (RUSLE) [9], which provide information on soil conservation capacities (i.e. how much soil can be conserved by the ecosystem). However, the challenge for soil conservation service assessment is on how to measure such service for its beneficiaries [10]. Therefore, further studies are required to identify the corresponding beneficiaries or benefiting areas and to build a feedback between nature and human system, in order to understand the impacts of changes on soil conservation supply to human well-being, as well as on human demand to soil conservation supply. To address the issues, we proposed a soil conservation service assessment framework that combines supply and demand of the soil conservation service as an integrated function. Following the framework, we proposed a new method to quantify soil conservation service supply and provided an overview about the supply and demand of soil conservation service from local to regional scale.

Current Opinion in Environmental Sustainability 2018, 33:136–141 This review comes from a themed issue on System dynamics and sustainability Edited by Bojie Fu and Yongping Wei

Received: 30 November 2017; Accepted: 12 May 2018 https://doi.org/10.1016/j.cosust.2018.05.011 1877-3435/ã 2018 Elsevier B.V. All rights reserved.

Introduction Soil erosion has the potential to change soil structure, negatively affects soil fertility and poses a threat to food Current Opinion in Environmental Sustainability 2018, 33:136–141

A general framework for soil conservation service assessment Ecosystem services (ESs) are the ecological characteristics, functions, or processes that directly or indirectly contribute to human wellbeing [11]. The crucial feature of ecosystem service concept is the link between ecosystem and human well-being, which considers both the products/functions provided by ecosystem and the beneficiaries which derive benefits from the ecosystem [12]. Ecosystem conditions and processes only become services once they are actually used or consumed by human beneficiaries [13]. As for soil conservation service, the ecosystem has the capacity to control erosion and facilitate sedimentation, depending on ecosystem structure and land management, especially the existing vegetation cover and root system. This capacity should be called the www.sciencedirect.com

Metacoupling supply and demand Zhao et al. 137

potential soil conservation service supply provided by ecosystem. Only after people use this service supply to maintain agricultural productivity or to improve water quality, we can say that it is the actual soil conservation service because the soil conservation service provision is used by beneficiaries to meet people’s demand and to contribute to human well-being [14]. Research on soil conservation services is closely related to soil erosion. There are many studies on soil erosion evaluation and the benefits gained from soil conservation. Yet most studies about soil conservation service pay more attentions on measuring soil conservation service supply, without considering the corresponding beneficiaries or benefiting areas. According to a recent review article, which reviewed 101 soil conservation service research articles, no measures emerged to quantify either the ES or the cascading benefits following the most accepted framework of ‘ecosystem properties-ecosystem functionsbenefits to humans-value’ [15]. Based on the aforementioned background, we presented a framework which coupled the service supply from nature system and demands from human system (Figure 1), and the work can be divided into three parts: first, evaluation on soil conservation supply and its benefits; second, evaluation on soil conservation demand; and third, analysis of soil conservation supply-demand, and subsequent measures or policy to improve service supply. The first step in soil conservation assessment is to connect the changes in ecosystem structure to soil erosion-

transport-export process that provides the soil conservation service supply [16], and to evaluate the potential soil conservation supply. In another word, we need to know how much soil can be retained by the ecosystem, and to characterize the benefits from soil conservation supply [17], such as any increase in food production, extended reservoir operation period, and improvement on water quality. The second step is to evaluate and to map the soil conservation demand by considering, for example, the Sustainable Development Goals (SDGs) of United Nations Development Programme. Based on these goals (e.g. Zero Hunger, Clean Water, or Life on Land), we need to identify how much soil erosion should be controlled (total demand of soil conservation service). In the third step, we can compare soil conservation service demand and actual soil conservation service supply, and identify the required supply in areas with low service provisioning. Then, some appropriate management measures or policy can be taken or made to improve the potential service supply which will in turn improve the actual service supply, meet demand from human system, and contribute to target (e.g. SDGs). This framework of soil conservation service provides a mechanism to couple human system and nature system which includes a two-way (feedback) analysis between soil conservation supply and demand.

Rethinking the method of quantifying soil conservation service supply According to the framework proposed above, quantifying soil conservation service supply is the first and an important step in providing reliable information on how different land use and global change affect the service supply. In most studies, soil conservation service provision is

Figure 1

Human System

Nature System

Potential supply

Realized demand

Land use

Erosion prevention

Food production

Zero hunger

Vegetation cover

Sediment retention

Reservoir operation period

Clean water

Soil property

Sediment transport

Water purification

Life on land

Ecosystem structure and composition

Ecosystem process and function

Required supply

Work flow

Benefits human derived

Sustainable development goals

Total demand

Service flow Current Opinion in Environmental Sustainability

A general framework to couple human–nature systems by soil conservation service assessment.

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138 System dynamics and sustainability

Figure 2

Maximum allowable rate of erosion

Positive value

Minus

Negative value Current erosion rate

Pixel soil retention value

Service supply

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Method to quantify the soil conservation service supply.

described as soil loss prevention by an ecosystem with current land use/land cover pattern and soil erosion control practice. Soil retention is the most commonly used indicator for the soil conservation service supply, which is calculated as the difference between potential maximum soil erosion rate (soil loss without vegetation cover and soil erosion control practice) and the current soil erosion rate (soil loss with current vegetation cover and erosion control practice) [18]. However, this method has caused some controversy related to the use of bare land as the baseline reference to evaluate soil conservation services. Bare land has high soil erosion, but rarely exists in reality. Instead of bare land, we suggested the use of soil loss tolerance value (T value) as a reference to evaluate soil conservation services. T value was first defined in 1940s as ‘the amount of soil that could be lost without decline in fertility, thereby maintaining crop productivity’ [19]. The definition of T value has evolved in to two themes in the last several decades [20], one is maintaining the dynamic equilibrium of soil quantity (mass/volume), the other is relating soil erosion tolerance to the biomass production function of soil. Though it may be difficult to give a uniform definition for T value, T value can be taken as a good reference to evaluate the soil conservation effects. If T value is higher than actual soil erosion, it means the soil conservation function of ecosystem has positive effects on human demand; while, if T value is lower than actual erosion, it means the soil conservation function of ecosystem has negative effects on human demand. We therefore argue that soil retention can be calculated as the maximum allowable erosion (T value) minus the current soil erosion. The formula is expressed as: ¼E ð1Þ DE where Emax cur maximum allowable rate of erosion maxisEthe (t ha1 y1) that can be expressed as T value and Ecur is the current erosion rate (t ha1 y1) and DE is the soil retention rate (t ha1 y1), which reflects the capacity of Current Opinion in Environmental Sustainability 2018, 33:136–141

ecosystem to control soil erosion (Figure 2). When the current soil erosion rate is less than T value, the value of DE is positive, indicating a good soil conservation service supply. If current soil erosion rate is greater than T value, the value of DE is negative, indicating a decreased erosion regulation service supply. Considering that there are different calculation methods for T value [20], more efforts should be allocated on selecting the most appropriate method of T value calculation.

Metacoupling soil conservation service supply and demand from local to regional scale Ecosystem service is ‘delivered’ from provisioning to benefiting areas through either biophysical or anthropogenic processes. After quantifying the supply of soil conservation service, the next crucial step is to characterize the demand for the service, which involves three components: first, identification of the beneficiaries and their location, second, indicators to measure social-economic benefits, and third, link to connect the soil conservation service with social-economic benefits. This link is crucial to underscore human dependence on ecosystem for erosion control [21,22,23]. The metacoupling framework, presented by Liu [24] in 2017 integrates human–nature interactions within a coupled system (intracoupling) as well as between adjacent coupled systems (pericoupling) and distant coupled systems (telecoupling). It also provides a platform to couple soil conservation service supply and demand across scales. The demand for erosion control is not only local, coming from the farming sector at risk of losing productive soils, but also regional, involving river users who desire clear water and prolonged reservoir operation period. Soil conservation service is ‘one directional flow related’ service, which is dependent on along a cascading effect [25]. www.sciencedirect.com

Metacoupling supply and demand Zhao et al. 139

Figure 3

Metacoupling

Enhance the soil conservation service Intracoupling

Pericoupling Upstream

Soil erosion Land productivity

Midstream

Telecoupling

Sediment yield Reservoirs ,water quality

Sediment transport Carbon cycle Sediment deposition Estuary formation

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Metacoupling soil conservation service supply and demand.

Along the soil erosion-transport-deposition pathway, upstream, midstream and downstream areas can be viewed as different human–nature system with the upstream area as the main service provisioning area. Therefore, soil erosion control by the ecosystem should provide multiple benefits from local to regional scale [26]. When the soil conservation service improves at the upstream area, it should benefit the upstream area (e.g. better soil fertility and land productivity or intracoupling). Meanwhile, in the pericoupling or telecoupling process, the upstream area provides service while midstream area and downstream area receives services. The upstream services can impact water quality and the operation period of reservoir in the mid-stream area (pericoupling), as well as on land-ocean sediment transfer and global C budget, respectively (telecoupling) (Figure 3).

Tradeoff analysis between soil conservation services and other ecosystems services During the research processes of soil conservation service, we also need to carry out two-way (feedback) analysis between human system and nature system. Ecosystem management from human system will not only affect the target process, but also trigger possible unprecedented effects on the target processes and/or non-target processes. Taking a restoration project, Grain for Green project in Loess Plateau of China as a case study, human influences and multiple ecosystem processes have been interconnected, and ecosystem management have cascading impacts at multiscales [27]. At the local scale, ecosystem restoration can bring positive effect, such as soil conservation and C fixation [28]. Unfortunately, it also led to some unprecedented environmental problems, such as dried soil layer and water shortage [29]. If these problems are prolonged, more negative effects may happen at larger www.sciencedirect.com

spatial and time scale, such as vegetation degradation, regional water shortage, and downstream wetland degradation. The disturbance effects on ecosystem are transmuting from one type to another, including to types that have not been considered. Based on the case study, we would like to put forward a new hypothesis of disturbance effect transmutation. The hypothesis believes that ecosystem management activities, such as ecosystem restoration project, will not only alter the target ecological or human process, but also other ecological or human processes and lead to some other disturbances on the human–nature coupled ecosystem at different scales. The disturbance effects can be divided into three kinds of disturbance effects (Figure 4). First, Disturbance effect I is the direct impact of disturbance on the target ecological process in the intra-area: vegetation restoration in Loess Plateau of China will help for soil conservation function in the local area. Second, Disturbance effect II is the direct impact of disturbance on nontarget ecological processes in the intra-area: vegetation restoration in Loess Plateau of China will improve C fixation function, but lead to dried soil layer in the long run; third, Disturbance effect III it is the indirect effects of above disturbances on non-target ecological processes in the peri-area or tele-area: vegetation restoration in Loess Plateau of China will lead to sediment load decrease, but water shortage in the midstream or downstream area of Yellow River. Only considering the target ecological process at one scale and ignoring other nontarget processes at multi-scales may generate unexpected environmental problems. Therefore, ecosystem management should include the tradeoff analysis between soil conservation services and other ecosystems services at

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140 System dynamics and sustainability

Figure 4

Local area of Loess Plateau

Direct impact on Grain for Green target process in Loess Plateau

Indirect impact on non-target processes

Disturbance effect transmutation

Carbon fixation

Dried soil layer

Direct impact on non-target processes

Vegetation

Soil conservation

restoration

Water shortage

Sediment load

Wetland degradation

decrease

Midstream/Downstream area of Yellow River

Direct impact on target process in the intra-area

Negative effect

Direct impact on non-target process in the intra-area Indirect impact on non-target process in the peri-or tele-area

Positive effect Current Opinion in Environmental Sustainability

Hypothesis of disturbance effect transmutation and application based on a case study in the Loess Plateau of China.

different scales, including the target and non-target processes.

Conflict of interests

Conclusions

Acknowledgements

The key feature of ecosystem service concept is a linkage between nature system and human system, as well as the bi-directional feedback between human and nature system via ecosystem service assessment. The framework for metacoupling soil conservation demand and supply from local to regional scale in this paper identified and provided measures to consider the effects of soil conservation provision on human-wellbeing and the feedback of human activities at different scales. Soil conservation services supply can be calculated as the maximum allowable erosion rate minus the current soil erosion rate, while soil conservation demand needs to consider defined targets such as the SDGs. Ecosystem management, such as ecosystem restoration project, will not only alter the target process, but also non-target processes, it may lead to unprecedented negative at different scales. Therefore, tradeoff analysis between soil conservation services and other ecosystems services at multiscales are necessary to understand the metacoupling soil conservation demand and supply.

This work was supported by National Key R&D Program of China (No. 2017YFA0604704), National Natural Science Foundation of China (No. 41771197), and State Key Laboratory of Earth Surface Processes and Resource Ecology (No. 2017-FX-01(2)).

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The authors declare that there is no conflict of interest regarding the publication of this article.

References and recommended reading Papers of particular interest, published within the period of review, have been highlighted as:  of special interest  of outstanding interest 1.

Amundson R, Berhe AA, Hopmans JW, Olson C, Sztein AE, Sparks DL: Soil science. Soil and human security in the 21st century. Science 2015, 348:1261071.

2.

Van Oost K, Verstraeten G, Doetterl S, Notebaert B, Wiaux F, Broothaerts N, Six J: Legacy of human-induced C erosion and burial on soil-atmosphere C exchange. Proc Natl Acad Sci U S A 2012, 109:19492-19497.

3.

Walling DE: Studying the impact of global change on erosion and sediment dynamics: current progress and future challenges. Isi Workshop. 2008.

4.

Wall DH, Six J: Give soils their due. Science 2015, 347:695.

5.

Kandziora M, Burkhard B: Mu¨ller F interactions of ecosystem properties, ecosystem integrity and ecosystem service indicators — a theoretical matrix exercise. Ecol Indic 2013, 28:54-78. www.sciencedirect.com

Metacoupling supply and demand Zhao et al. 141

6.

Rao E, Ouyang Z, Yu X, Xiao Y: Spatial patterns and impacts of soil conservation service in China. Geomorphology 2014, 207:64-70.

7.

Chiang LC, Lin YP, Huang T, Schmeller DS, Verburg PH: Simulation of ecosystem service responses to multiple disturbances from an earthquake and several typhoons. Landsc Urban Plan 2014, 122:41-45.

8.

Fu BJ, Liu Y, Lu¨ YH, He CS, Zeng Y, Wu BF: Assessing the soil erosion control service of ecosystems change in the Loess Plateau of China. Ecol Complex 2011, 8:284-293.

9.

Hamel P, Chaplin-Kramer R, Sim S, Mueller C: A new approach to modeling the sediment retention service (InVEST 3.0): case study of the Cape Fear catchment, North Carolina, USA. Sci Total Environ 2015, 524–525:166-177.

10. Guerra CA, Pinto-Correia T, Metzger MJ: Mapping soil erosion prevention using an ecosystem service modeling framework for integrated land management and policy. Ecosystems 2014, 17:878-889. 11. Costanza R, Groot RD, Braat L, Kubiszewski I, Fioramonti L, Sutton P et al.: Twenty years of ecosystem services: how far have we come and how far do we still need to go? Ecosyst Serv 2017, 28:1-16. 12. Serna-Chavez HM, Schulp CJE, Bodegom PMV, Bouten W, Verburg PH, Davidson MD: A quantitative framework for assessing spatial flows of ecosystem services. Ecol Indic 2014, 39:24-33. 13. Fisher B, Turner RK, Morling P: Defining and classifying ecosystem services for decision making. Ecol Econ 2009, 68:643-653. 14. Jones L, Norton L, Austin Z, Browne AL, Donovan D, Emmett BA  et al.: Stocks and flows of natural and human-derived capital in ecosystem services. Land Use Policy 2015, 52:151-162. This paper demonstrates the difference between potential ecosystem service supply and actual ecosystem service provision 15. Boerema A, Rebelo AJ, Bodi MB, Esler KJ, Meire P: Are  ecosystem services adequately quantified? J Appl Ecol 2017, 54:358-370. This paper reviewed 405 peer-reviewed ES research papers to address the question: ‘Is the biophysical and socio-economic reality of ES adequately quantified? And assess which part of the ES cascade was measured: the ecosystem property, function, service, benefit or value. The results reveal that no paper quantify the ES part of the cascade. 16. Fu BJ, Wang S, Su CH, Forsius M: Linking ecosystem processes and ecosystem services. Curr Opin Environ Sustain 2013, 5:4-10. 17. Burkhard B, Kroll F, Nedkov S et al.: Mapping ecosystem service supply, demand, and budgets. Ecol Indic 2012, 21:17-29. 18. Jiang C, Wang F, Zhang H, Dong X: Quantifying changes in multiple ecosystem services during 2000–2012 on the Loess Plateau, China, as a result of climate variability and ecological restoration. Ecol Eng 2016, 97:258-271.

www.sciencedirect.com

19. Singh RK, Somasundaram J, Lakaria BL, Mandal D, Sethy BK, Sinha NK, Lal R: Using credible soil loss tolerance value for conservation planning and managing diverse physiographic regions in Rajasthan. Agric Res 2017, 6:169-178. 20. Verheijen FGA, Jones RJA, Rickson RJ, Smith CJ: Tolerable versus actual soil erosion rates in Europe. Earth Sci Rev 2009, 94:23-38. 21. Arkema KK, Griffin R, Maldonado S, Silver J, Suckale J, Guerry AD: Linking social, ecological, and physical science to advance  natural and nature-based protection for coastal communities. Ann NY Acad Sci 2017, 1399:5-26. The authors develop an ecosystem services framework that propagates the outcome of a management action through ecosystems to societal benefits and apply it to two case studies to illustrate how estimates of multiple benefits and losses can inform restoration and development decisions 22. Bagstad KJ, Johnson GW, Voigt B et al.: Spatial dynamics of ecosystem service flows: a comprehensive approach to quantifying actual services. Ecosyst Serv 2013, 4:117-125. 23. Fang XN, Zhao WW, Fu BJ, Ding JY: Landscape service capability, landscape service flow and landscape service demand: a new framework for landscape services and its use for landscape sustainability assessment. Prog Phys Geog 2015, 39:817-836. 24. Liu J: Integration across a metacoupled world. Ecol Soc 2017,  22:29. This paper presents a metacoupling framework that integrates human– nature interactions within a coupled system (intracoupling) as well as between adjacent coupled systems (pericoupling) and distant coupled systems (telecoupling) and provides a platform to couple ecosystem service supply and demand across scales. 25. Costanza R: Ecosystem services: multiple classification systems are needed. Biol Conserv 2008, 141:350-352. 26. Fu BJ, Zhang LW, Xu ZH, Zhao Y, Wei YP, Skinner D: Ecosystem services in changing land use. J Soils Sediment 2015, 15:833843. 27. Fu BJ, Wang S, Liu Y, Liu JB, Liang W, Miao CY:  Hydrogeomorphic ecosystem responses to natural and anthropogenic changes in the loess plateau of china. Annu Rev Earth Plant Sci 2017, 45:223-243. This paper reveals the implementation of the Grain for-Green Project has significantly reduced both runoff and sediment from the Loess Plateau, which has both advantages and disadvantages for the lower Yellow River and argues that the Current net primary production of vegetation in the Loess Plateau is approaching the threshold beyond which further regional water use would be unsustainable. 28. Wang S, Fu B, Piao SL, Lu¨ YH, Ciais P, Feng XM et al.: Reduced sediment transport in the yellow river due to anthropogenic changes. Nat Geosci 2015, 9:1-4. 29. Feng XM, Fu BJ, Piao SL, Wang S, Ciais P et al.: Revegetation in China’s Loess Plateau is approaching sustainable water resource limits. Nat Clim Change 2016, 6:1019-1022.

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