Development of an ecological security evaluation method

Ecological Indicators 39 (2014) 153–159Contents lists available at ScienceDirectEcologicalIndicatorsj o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /e c o l i ndDevelopment of an ecological security evaluation method based on the ecological footprint and application to a typical steppe region in ChinaXiaobing Li ∗,Meirong Tian,Hong Wang,Han Wang,Jingjing YuState Key Laboratory of Earth Surface Processes and Resource Ecology,College of Resources Science and Technology,Beijing Normal University,Beijing 100875,Chinaa r t i c l ei n f oArticle history:Received 20June 2013Received in revised form 5December 2013Accepted 15December 2013Keywords:Ecological footprint Typical steppeEcological security Evaluation methodSustainable developmenta b s t r a c tThe steppes of Inner Mongolia lie in a region which are sensitive to global climate change.The region forms an important ecological barrier against sandstorms and it is also strategically important for the development of China’s energy and mineral resources.To describe the influence of resources exploitation on the ecological security of the typical Inner Mongolian steppe,we developed a consumption footprint pressure index (CFPI)and a production footprint pressure index (PFPI)based on the ecological footprint concept,and developed an ecological footprint contribution index (EFCI)to assess the pressures created by transferring resources and products from output areas to input ing these indices,we devel-oped a coupled ecological security assessment model to evaluate the ecological security level of the typical steppe.We used the model to calculate CFPI,PFPI,and EFCI for the steppe area for three counties and one urban region of Inner Mongolia from 2001to 2010.We found that CFPI and PFPI increased throughout the study period in most regions.In addition,EFCI was generally positive,which indicated the ecological security of the typical steppe was affected primarily by the electricity and production output processes.Our results suggest that the ecological security of the study area has been at serious risk since 2005.© 2013 Elsevier Ltd. All rights reserved.1.IntroductionIn China,population growth and socioeconomic development have been accompanied by depletion of energy resources due to excessive consumption (Dai et al.,2010).This has gradually led to serious ecological degradation and environmental dam-age,which have challenged individuals,communities,and regions.Meanwhile,finding ways to guarantee the health and sustain-able development of regional ecosystems despite of rising energy and resource demand has become the focus of research around the world (Hodson and Marvin,2009),ecological security con-cept appeared in due course.Ecological security was considered as strategically important as national defense,economic security,and financial security (Andersen and Lorch,1998;Duffy et al.,2001;Kullenberg,2002;Bonheur and Lane,2002).Maintaining global and regional ecological security,and thereby permitting sustain-able socioeconomic development,has become the consensus goal of the international community.Ecological security evaluation is comprehensive,and the main methods that have been used include the pressure-state-response∗Corresponding author.Tel.:+861058807212;fax:+861058807212.E-mail address:tianmeirong007@ (X.Li).model (Tong,2000),the system clustering method (Lundquist,2002),the ecological footprint method (Wackernagel,1998;Lenzen and Murray,2001;Huang et al.,2007;Li and He,2011;Bartel,2000),the comprehensive index method (Bartel,2000),the fuzzy comprehensive evaluation method (Onkal-Engin et al.,2004),and the neural network models (Chen,2004).Among the quantitative methods for ecological security assessment,the ecological footprint method is simple and clear in terms of concept and principles.It has therefore been applied in long-term studies of ecological risk and in regional comparisons (Stoglehner,2003;Collins et al.,2006;Senbel et al.,2003;Wackernagel et al.,2004,2006).Also this approach can become an easy-to-read measurement tool for ecological sustaina-bility (Wackernagel et al.,1999),which can also be used to judge whether a country’s or a region’s development remains within the biocapacity by comparing the consumption and production of resources in the region,thereby reveals the regional ecologi-cal security status and the potential for sustainable development (Chen et al.,2010;Liu et al.,2011).China’s Inner Mongolia Autonomous region covers about 12.5%of the country’s total land area.It is famous for its lush grasslands and rich mineral resources,and has become main output area of coal resources in China.Given the importance of coal as an energy source in China,the region therefore provides an important con-tribution to the country’s socioeconomic development.However,1470-160X/$–see front matter © 2013 Elsevier Ltd. All rights reserved./10.1016/j.ecolind.2013.12.014154X.Li et al./Ecological Indicators39 (2014) 153–159Fig.1.Location of the study area.this region also plays a vital role as an ecological barrier in north-ern China.The typical steppes of Inner Mongolia lie within the Northeast China Transect under the International Geosphere Bio-sphere Program(IGBP)which is a sensitive area of the global change (Zhang et al.,1997).However,continuous socioeconomic develop-ment with excessive exploitation of resources could induce soil and water loss and grassland degradation(Zhu and Qin,2008; Qing et al.,2013),which threatened the ecological security of the steppes.In this paper,we will introduce the study area and describe our data sources;provide an overview of the ecological footprint method and the concept of biocapacity,and propose three indices, the production footprint pressure index(PFPI),the consumption footprint pressure index(CFPI)and ecological footprint contribu-tion index(EFCI),which we use to develop a coupled ecological security assessment model and evaluate the ecological security of four typical steppe areas as well as analyze and discuss the implica-tions of our results.The general objective of the study is to measure the pressure imposed by the outside regions to the study area, thereby providing a basis for developing a plan for more sustainable regional development.2.Study areaThe typical steppes in the study were locate in the eastern part of Inner Mongolia,covering an area of1.1×105km2(Fig.1).Our study area comprises three counties and one urban region:Abag County, East Ujimqin County,West Ujimqin County and Xilinhot City.The study area has a continental arid to semiarid climate,with annual average temperatures of−1to4◦C,an annual mean precipitation of 150–450mm,and an annual evaporation of1600–2400mm,which increases from east to west.The elevation decreases gradually from 1800m in the southeast to800m in the northwest.The vegetation is dominated by xeromorphic grasses such as Stipa grandis P.Smirn, Stipa krylovii Roshev,Leymus chinensis Tzvel,Cleistogenes squarrosa Keng et al.The population in the study area had grown gradually,increas-ing from3.0×105in2001to3.5×105in2010.With the rapid socioeconomic development,per capita GDP increased to nine times of its original level,from1×104RMB in2001to9×104 RMB in2010.Simultaneously,energy consumption had increased rapidly from0.34Mt sce(standard coal equivalent)in2001to 2.8486Mt sce in2010.During this period,the electricity supply increased from429.36GW-h to495.88GW-h.3.Methods3.1.Evaluation model of ecological footprint and biocapacityEcological footprint is a kind of simple methodology but com-prehensive way for accounting the fundamental conditions for sustainability.It is a resource and emissions accounting tool measuring direct and indirect human demand for the planet’s regenerative capacity(biocapacity)and comparing it with the biocapacity available on the planet(Wackernagel et al.,1999; Monfreda et al.,2004;Galli et al.,2012a,b),there are six land-use types for measuring the ecological footprint:cropland,forestland, grazing land,fishing grounds,built-up land,and carbon uptake land (for the absorption of anthropogenic carbon dioxide emissions) (Galli et al.,2012a,b;Borucke et al.,2013)The ecological footprint (EF)can be expressed in the unit of global hectares-gha(Monfreda et al.,2004;Bastianoni et al.,2012;Galli et al.,2012a,b)through a multi-step process,as follows:EF=QY n×Y×r=QY n×Y nY w×r=QY w×r(1)where Q is the amount of a product harvested or CO2emitted,Y n is the national average yield for the product Q(or its carbon uptake capacity in cases where Q is carbon dioxide),and Y and r are the yield and equivalence factors respectively,for the land use type in question.Y is evaluated annually as the ratio of the local yield for production of a generic product(Y n)to the yield for production of the same product in the world(Y w)as a whole(Galli et al.,2007).In order to properly allocate the embodied footprints carried by tradeflows of products and keep track of the biocapacity,Consump-tion Ecological Footprint(EF C)is calculated by adding the footprint embedded in locally produced products(EF P)and the imported or input products(EF I)and subtracting the footprint of exported or output products(EF E)(Galli et al.,2012a,b;Borucke et al.,2013),to thefinal footprint value as in Eq.(2):EF C=EF P+EF I−EF E(2) Among six land-use types,the carbon uptake land is exclusively dedicated to track a waste product:carbon dioxide,since most ter-restrial carbon uptake in the biosphere occurs in forests,so carbon uptake land is assumed to be forest land by the ecological footprint methodology(Borucke et al.,2013),as in Eq.(3):EF carbon uptake land=P c(1−S ocean)Y c×r(3)where P c is the annual anthropogenic emissions(production)of carbon dioxide;S ocean is the fraction of anthropogenic emissions sequestered by oceans,about one-third of anthropogenic emissions are absorbed by the oceans from the total anthropogenic emissions (IPCC,2001);Y c is the annual rate of carbon uptake per hectare of world average forest land.Biocapacity reflects the entire biologically productive area and represents the maximum level of resource supply,which is the counterpart of the footprint(Wackernagel and Rees,1996;X.Li et al./Ecological Indicators39 (2014) 153–159155 Wackernagel et al.,1999;Monfreda et al.,2004).The calculationof the total biocapacity(BC)can be expressed as follows:BC=ni=1a i×r i×Y iwhere a i is the real land area for the i th category of land type (gha),Y i is the yield factor of the i th category of land type,and r i is the equivalence factor of the i th category of land type.In cal-culating BC,we adopted the suggestion of the World Commission on Environment and Development that the area of biologically pro-ductive land should be decreased by12%to account for biodiversity conservation.The data used in the calculation of ecological footprint and bio-capacity are drawn from the Statistical Yearbooks of Abag County, East Ujimqin County,West Ujimqin County,and Xilinhot City that were published by the local governments from2002to2011; Though the yield factors and equivalence factors may alter due to the land use pattern and regional technology development in different years,the variation is normally slight to affect the total time series of ecological footprint,thus,we refer the value of the yield factors to the other papers in the calculation(Xu et al.,2003; Wackernagel et al.,1999);the calculation of P c is on the basis of the accounting methods of carbon dioxide emissions published in the Fourth Assessment Report(AR4)of the United Nations Inter-governmental Panel on Climate Change(IPCC,2007;Li,2013),Y c is obtained from relevant literature(Venetoulis and Talberth,2008).3.2.Evaluation model of ecological securityBoth ecological footprints and biocapacity use standardized hectares that allow for the meaningful comparison between each other.Hence,aggregate human demand(ecological footprint)and nature’s supply(biocapacity)can be directly compared to each other.The component and aggregate areas are commensurable. Meanwhile,the comparison result reveals whether the existing natural capital is sufficient to support the current consumption and production patterns(Monfreda et al.,2004).Because of the regional trade in energy and products,the ecological pressure of resource output area come both from local production/consumption of resources and energy and from consumption of resources during production processes at a higher level.Thus,the ecological pres-sure must account for both resource-output areas and resource input areas,in proportion to the ratio of product consumption to production.3.2.1.CFPIIn this paper,we accounted for consumption pressure by using the CFPI index:CFPI=EF cBC(7)CFPI mainly reflects the ecological pressure which is caused by the consumption of resources and sequestering carbon diox-ide emissions etc.in the industry and daily life of local residents. If CFPI>1,the consumption footprint is greater than the BC in the study area,leading to an ecological deficit that can only be mitigated by importing resources from outside or overuse of local resources. If CFPI<1,the consumption footprint is less than the BC,which means the region is ecologically secure and there is the potential for additional development.If CFPI=1,the system is in equilibrium between consumption and BC.3.2.2.PFPIIn this paper,we accounted for production pressure by using the PFPI index:PFPI=EF pBC(8) where EF p is production ecological footprint,PFPI mainly reflects the production pressure for producing food and generating elec-tricity and so on.If PFPI>1which means the production consumes the local natural resources excessively leading to ecological over-shoot;If PFPI<1,the production footprint is less than the BC,which indicates that production is ecologically safe and that there may be room for additional development.If PFPI=1,the system is in equilibrium between production and BC.3.2.3.Ecological footprint contribution index(EFCI)We determined the balance between production and consump-tion pressure using the EFCI index:EFCI=EF p−EF cEF c(9)If EF p>EF c,EFCI will be positive,and the study area is defined as a resource and product output area.This means that local ecolog-ical security is affected by both local and external production and consumption,but that production is playing a more important role; as a result,the ecological pressure will be transferred from input to output area influencing the local ecological security.If EF p<EF c, EFCI will be negative,which means that the production level cannot satisfy the consumption demand in the study area,and the level of ecological security will be determined primarily by the consump-tion footprint.If EF p=EF c,EFCI will be zero,which means that the system is in equilibrium between production and consumption.3.2.4.Coupled ecological security assessment modelTo describe the ecological security of a study area,we define the parameter T,whose value represents the dominant parameter (production or consumption)for that area:If EFCI≥0,then T=PFPIIf EFCI<0,then T=CFPI(10)Table1summarizes the levels of ecological security based on the parameters in this model.4.Results4.1.Variations of the ecological footprint and BCThe national energy account needs to be corrected because of trade(Wackernagel et al.,1999),and so does the ecological foot-print account due to the same reason,some of the carbon footprint which come from consuming energy needs to be deducted from the ecological footprint account as energy is consumed to pro-duce export goods,while the carbon footprint embodied in import goods needs to be added.However,the study area is a relatively small administrative district for which the import/export data is not available,thus the impact of trade on the ecological footprint, will distorts the relative size of footprints of consumption,but we will be able to calculate the net input or output ecological footprint via the comparison of footprint of production and consumption, and then to judge whether the pressure for the ecological security is from resource output or excessive consumption.The results of EF p and EF c of the study area were shown in Figs.2and3,which gener-ally increased from2001to2010.The production footprint in2010 had increased to1.81times its2001value of1.65×106gha,reach-ing3.00×106gha in2010(Fig.2),socioeconomic development accelerated the food production and the electricity generation,156X.Li et al./Ecological Indicators 39 (2014) 153–159Table 1Summary of the coupled ecological safety assessment model.ScenarioIndexEcological security stateInterpretationEFCI ≥0(EF p ≥EF c )T =PFPIPFPI >CFPI >1Very riskyThe production footprint and consumption footprint are beyond the BC,so the ecological pressuretransferred from outside the study area increases,thereby increasing the threat to ecological security is decided by both PFPI and CFPI1≥PFPI >CFPIT <0.5very safe The production and consumption footprints are both within the BC,so the study area has potential for additional development0.5≤T <0.8safe0.8≤T ≤1.0not very safe PFPI >1,CFPI <1RiskyThe consumption footprint is within the BC,but the production footprint exceeds BC,so the threat to ecological security is decided by the PFPIEFCI <0(EF p <EF c )T =CFPICFPI >PFPI >1Very riskyThe production and consumption footprints arebeyond the BC,so the threat to ecological security is decided by both CFPI and PFPI1≥CFPI >PFPIT <0.5very safe The production and consumption footprints are both within the BC,so the study area has the potential for additional development0.5≤T ≤0.8safe0.8≤T ≤1.0not very safe CFPI >1,PFPI <1RiskyThe production footprint is within the BC,but theconsumption footprint is beyond the BC,so the threat to ecological security is decided byCFPIFig.2.Changes in the production footprint and biocapacity (BC)in the typical Inner Mongolian steppe from 2001to 2010.especially in Xilinhot City;the growth of the production footprint accelerated accordingly.The growth rate of EF p of Xilinhot City was higher than those of the other areas,and accounted for 38.5%of the total production footprint in 2010.The EF c increased to 4.51times its 2001value of 0.62×106gha,reaching 2.80×106gha in 2010(Fig.3)as a result of improvements in the regional standard of living.BC changed slightly,from 1.16×106gha in 2001to 1.31×106gha in 2010,because the dominantbiologicallyFig.3.Changes in the consumption footprint and biocapacity (BC)in the typical Inner Mongolian steppe from 2001to 2010.productive land type of the steppe was grassland,and the areas of other types of productive land only changed slightly during this period.The EF p was higher than the BC from 2001to 2010(Fig.2),and the gap between them means the production consumed the local natural resources excessively leading to ecological overshoot.The EF c was lower than the BC from 2001to 2004,which means resources used and wastes produced can be afforded in the range of the biocapacity and the region is ecologically secure and there is the potential for additional development.However,the consump-tion footprint was higher than the BC thereafter,indicating that the typical steppes are experiencing an ecological deficit because of their demand for resources is not met by a sufficient local supply,expressed by BC.Since there is little import from other districts,it has to rely on the overuse of local resources with respect to higher local demand.4.2.Changes in CFPI,PFPI,and EFCIUsing our coupled evaluation model for ecological security,we calculated the ecological footprint and BC for each of the regions,and used the resulting CFPI,PFPI,and EFCI values for total study area,Abag County,East Ujimqin County,West Ujimqin County,and Xilinhot City based on the relevant statistical data from 2001to 2010.According to the coupled model,if both PFPI >1and CFPI >1,the ecological security was considered to be very risky,whereas if CFPI <1and PFPI >1or CFPI >1while PFPI <1,the ecological secu-rity was considered to be risky.Our results showed that the total study area was very risky from 2005to 2010and was risky from 2001to 2004(Fig.4a).Abag County was risky until 2009,and only 2010became very risky (Fig.4b).East Ujimqin County was risky from 2001to 2007and 2009,and the other years was very risky (Fig.4c).West Ujimqin was risky from 2001to 2006and thereafter became very risky (Fig.4d).Xilinhot City was very risky through-out the study period (Fig.4e).According to the analysis the changes in the consumption footprint and production footprint of different land use types from 2001to 2010for total study areas (Fig.5a and b),we can find that the risk mainly comes from grazing land in terms of production footprint,since the typical steppe covers 88%of the total study area,and the biocapacity varied from 0.80×106gha to 0.84×106gha,which was much lower than the production foot-print ranging from 1.38×106gha to 1.96×106gha in the same period from 2001to 2010;Regarding the consumption footprint,X.Li et al./Ecological Indicators 39 (2014) 153–159157E F C IP F P I a n d C F PIE F C IP F P I a n d C F PIE F C IP F P I a n d C F CIE F C IP F P I a n d C F CIE F C IP F P I a n d C F PIFig.4.(a)Changes in the production footprint pressure index (PFPI),consumption footprint pressure index (CFCI),and ecological footprint contribution index (EFCI)in total study area.(b)Changes in the production footprint pressure index (PFPI),consumption footprint pressure index (CFCI),and ecological footprint contribution index (EFCI)for Abag County.(c)Changes in the production footprint pressure index (PFPI),consumption footprint pressure index (CFCI),and ecological footprint contri-bution index (EFCI)for East Ujimqin County.(d)Changes in the production footprint pressure index (PFPI),consumption footprint pressure index (CFCI),and ecological footprint contribution index (EFCI)for West Ujimqin County.(e)Changes in the production footprint pressure index (PFPI),consumption footprint pressure index (CFCI),and ecological footprint contribution index (EFCI)for Xilinhot City.the risk is mainly induced by the carbon uptake land,which raised 14.8times from 0.14×106gha in 2001to 2.18×106gha in 2010,because of the requirement for the energy consumption,which lead to carbon dioxide emissions during the socioeconomic develop-ment.Most of the EFCI values were greater than 0,except for Xilinhot City from 2002to 2010,total study area and West Ujimqin County at 2008,and East Ujimqin County at 2010(Fig.4a–e).This means that the ecological security was determined primarily by the PFPI,asaFig.5.(a)Changes in the production footprint of land use types from 2001to 2010for total study areas.(b)Changes in the consumption footprint of land use types from 2001to 2010for total study areas.result of increasing PFPI,the ecological pressure transferred from outside the region increased obviously and increasingly threatened the local ecological security.EFCI showed a trend of decrease in the study area,which means that although the threat to ecologi-cal security came primarily from the production of resources but the influence of external pressure on ecological security begins to change to internal pressure.EFCI values were less than 0in Xil-inhot City after 2001,this means that the ecological security was determined primarily by the CFPI.The local consumption structure should be adjusted to add more input resources from outside and reduce the over-consumption of local resources in order to reduce CFPI,and then the ecological deficit.5.DiscussionMost of EFCI was positive,and PFPI or CFPI were greater than 1.These results indicated that the region’s ecological security was threatened more by outputting electricity and other products than by local consumption pressure.The gross national product (GNP)of our study area in Inner Mongolia increased to 7.77times its 2001value of 41.46×109RMB,reaching 322.21×109RMB in 2010.This rapid development accelerated the production and consumption of resources,as a result,the production footprint increased to 12.24times its 2001value,which was faster than the GNP growth rate.In addition,the development was achieved at the cost of exces-sive exploitation of the region’s resources.Based on our model for evaluating ecological security,the only effective way to reduce this158X.Li et al./Ecological Indicators39 (2014) 153–159ecological pressure and improve the level of ecological security would be to decrease the production footprint or improve the BC. However,the BC changed only slightly because most of the land use was pasture,which accounted for89%of the total land area; the other land-use and cover types had little impact on the BC. Therefore,improving the level of ecological security will require a reduction of the production footprint by means of more appropri-ate allocation of resources.Therefore,ecological protection of the steppes should focus on more efficient resource allocation,thereby mitigating the threat to the ecological security caused by socioeco-nomic development and helping to achieve sustainable utilization of the region’s resources.The EF methodology uses data on energy and resources con-sumption,waste generation(measured as carbon dioxide)to estimate the total ecosystem area(in terms of global average hectares–gha)(Kissinger et al.,2013),Which requires a consid-eration of both consumption footprint and production footprint. There are six land-use types for measuring the EF,which is con-trasted withfive demand categories of BC.The reason for this discrepancy is that two demand categories,forest products and carbon sequestration,compete for the same biocapacity category: forest land(Borucke et al.,2013).Both EF and BC use standard-ized hectares to measure the demand on natural capital versus the ability of natural capital to meet the demand.Hence,the component and aggregate areas are commensurable(Monfreda et al.,2004).On this basis,we introduced the PFPI,CFPI,and EFCI parameters to clarify the root causes of the threats to ecological security.In future research,these indices should be expanded so that our analysis can account for more of the factors that determine mankind’s ecological footprint and its impacts on the biocapac-ity.Because unified statistics and the data of import and export were not available in each county’s statistical yearbooks,we adopted common items in selecting the consumption and production items that formed the basis of our calculations.This means that the results for each area cannot be fully compared,but that we can still use the relative changes to compare the regions.Thus,our analysis provides a useful measure of the changes in regional ecological security over time.The coupled assessment model considers the relationship between ecological security and local production and consumption pressures,and thereby reflects the pressure on the local environment created by the production of resources as well as their consumption.However,it will be necessary tofind ways to further improve the ecological security.This will be the subject of our future research.AcknowledgmentsThe research was funded by the National Natural Science Fund of China(number:41030535),the National Key Basic Research Program of China(2014CB138803),the Program for Changjiang Scholars and Innovative Research Team in Uni-versity(IRT1108),and the International Cooperation Project (2013DFR30760).ReferencesAndersen,P.P.,Lorch,R.P.,1998.Food security and sustainable use of natural resources:a2020vision.Ecol.Econ.26,1–10.Bartel,A.,2000.Analysis of landscape pattern:towards a“top-down”indicator for evaluation of land use.Ecol.Model.130,87–94.Bonheur,N.,Lane,B.D.,2002.Natural resources management for human security in Cambodia’s Tonle Sap Biosphere Reserve.Environ.Sci.Pollut.5,33–41. 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