中国生态交错带

Dec. 2012Journal of resources and ecologyVoL 3 No 4J Resou.Ecol.20123(4)297-307ArticleDo:10.5814ssn.1674-764X201204002www.jorae.cnypical Ecotones in ChinaGAO Jixi*, LV Shihai, ZHENG Zhirong and LIU JunhuiI Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection of China, Nanjing 210042, China;2 State Environmental Protection Key Laboratory of Regional Eco-process and Function Assessment, Chinese Research Academy of EnvironmentalSciences(CRAES), Beijing 100012, ChinaAbstract: An ecotone is a transition area between two biomes or two different ecosystems and are oftenfragile, sensitive and variable. Since the 1970s the study of the ecotone has increasingly gained notorietyas an important facet of ecological research. China, with a vast complex geology, climate and vegetation,is home to a variety of ecotones. this variety is witnessed in breeds, scales and sizes. This vast array hasnot only laid a solid foundation fortific research but also enhanced Chinas economic developmentsocial development and cultural diversity conservation. according to the geographical distribution andecological features of China s large scale ecotone, The trinity index system" has been establishedincluding land use types, natural climate characteristics and agricultural economic development to classifyand defne the spatial distribution of typical ecotones in China. Based on this classifcation, the naturalenvironmental characteristics, environmental fragility and the existing problems of five kinds of typicalecotones have been studied. This study will lead to a comprehensive understanding of the evolutionarypatterns of ecotonesKey words: ecotones: classifcation; characteristics; existing problems and countermeasuresKevin and Thomas 2006; Temuulen 2005; Wang et al. 2000)1 IntroductionChina has a vast territory with a complex and changingEcotone refers to a transition area between two biomes or geology, climate and vegetation, and is consequently hometwo different ecosystems(Odum 1971). Since the ecotone to a variety of ecotones. This variety is witnessed in breeds,was first proposed by F. E. Clements in 1905, many have scales and sizes. This vast array has not only laid a solidcontributed to ecotone research and theory. A focus on foundation of scientific research but enhanced China'secotones has also played an important role in protecting economic development, social development and culturalecological environment and enhancing industrial and diversity conservation. The rational selection of a typicalagricultural development. Especially since the 1970s, the ecotone, the in-depth study of its spatial distribution laws,study of the ecotone has increasingly gained notoriety as an characteristics of natural environment as well as the fragilityimportant facet of ecological research.of the ecological environment will lead to a comprehensiveThe ecotone possesses many unique natural attributes understanding of the evolutionary patterns of ecotonessuch as the distinctiveness of edge efects( Clements 1905 This study will play a significant role in protecting regionaHardt 1989), non-continuity of vegetation distribution, ecological environments and optimizing economic structuresheterogeneity in landscape structure(Walker 1979, 1985and the fragility of the ecological environment. These 2 Defining ecotonesattributes guide the study of ecotones and play an important According to Clements(1905), the ecotone refers to theand irreplaceable role in the exploration of natural ecological overlapping stress zone of plant associations determined bylaws and protection of the ecological environment. For these climate, which can be classified into local edges or margins,reasons, the ecotone has increasingly received attention from the treeline and biome ecotone(Clements 1905: risser 1995)scientists and governments(Di Casstris and Hansen 1992; The ecotone defined in the literature afterwards refers toReceived: 2012-05-24 Accepted: 2012-11-21中国煤化工Foundation: Specific Research on Public Service of Environmental Protection in China(No. 2011(Special Commonweal Study on Environmental Protection of China(No. 201209027)CNMHCorresponding author: GAO Jixi. Emial: gjx(@nies.orgJournal of Resources and Ecology VoL 3 No 4, 2012the ecotone between two different ecological communities basis of evaluation and subdivision according to the natural(Tansley and Chipp 1926; Odum 1983). Today's generally distribution law, inconsistent with administrative regionsaccepted definition of ecotone was proposed in the SCOPE However, most human activities are significantly influencedmeeting in Paris, France in 1987: The ecotone refers to and restricted by administrative divisions. Therefore, in thisthe transition zone between adjacent ecosystems, having paper the classification of ecotones is not only conducteda set of characteristics uniquely defined by space and time on the basis of the integrality of administrative regionsscales and by strength of the interactions between adjacent (counties, cities and districts), but also on the continuity ofecological systems"(Holland 1988). We define ecotones spatial ecotones according to similarities in environmentalas the transition zone where one ecosystem is changing to characteristicsanother and the environmental factors as well as biologicalgroups are in a critical state. In ecotones, the structure3. 1.3 Grading principlefunction and processes of ecosystems are so complex that Ecotones differ in their spatial scales and structure levels.Ifthey will be extremely sensitive to changing climates and ecotones are classified hierarchically, it will help to identifyhuman interferences. Therefore, ecotones can be viewed not environmental problems at different scales and lay a solidonly as the signal amplifier from outside interference but also foundation for environmental management and decisionas an important warning zone for research on global change. makers to implement measures and accurately grasp3 Classification of ecotonesenvironmental problemsBased on the geographic distribution of ecotones, China's3. 1. 4 Service and governancetypical ecotones have been classified according to the The classification of ecotones should be conductednational standards for land use, ecosystem, agro-climate and according to their natural attributes, causes and fragilityIt will be convenient to formulate practical measures and3.1 Classification principlemanagement programs to ensure the stability of the systemstructure and continuity of ecological functions in the3. 1. 1 Comprehensive and dominant principleDue to the fact that the characteristics, compositions, 3.2 Classification index systemdistribution patterns, functional effects and formations ofecotones are extremely complex, existing environmental According to the geographical distribution, ecologicalproblems will be affected by many factors. Therefore, features of China's large scale ecotone and the national landseeking the dominant factor on the basis of considering type classification standard, " The trinity index system"hasall kinds of affecting factors comprehensively will help to been established including land use types, natural climateestablish desired goalscharacteristics and agricultural economic developmentBased on this index system, we define the spatial3. 1.2 Integrality of each specific regiondistribution of typical ecotones in China(Table 1)Theoretically, ecotone types should be classified on theTable 1 The spatial definition indexes of typical ecotones in ChinaEcotone typesLand use pattemsNatural climate characteristics AForest-steppe ecotone in Forest and grassland mosaicAnnual precipitation 350-500 mm, Animal husbandry accounted for moreNorth chinadistribution, and woodland area ratio aridity 0.6-1.0than 60% of agricultural economyis less than 30%arming-pastoralDominated by grass, and farmland Annual precipitation 300-450 mm, Farming herd coexists, cultivateecotone in North China area less than 30%aridity 1.0-2.0industry accounted for more than 60%of agricultural economyDesert-oasis ecotone in Dominated by desert, oasisAnnual precipitation <150 mm, Farming herd coexists, crop occupiesNorthwest Chinadistribution was mosaic and the area aridity >4.060% aboveis less than 30%The Sichuan-Yunnan Altitude 2500-4500 m in southwest Annual precipitation >1000Agriculture -forestry-animal-husbandrymountain area, vertical distribution mm, abovel0C accumulatedcoexist, animal husbandry accountedecotone in Southwest of forest and grassland, ravine area of temperature 500 4000Cfor more than 30% of agriculturalChinafarmland area less than 30%economyEastern marine-Eastern marine-terrestrial interlaced Annual precipitation >80oH中国煤化工 r more than60%terrestrial ecotonezone, there is significant tidal wetland across temperate, trorubtropical zonesCNMHGGAO Jixi, et aL. Typical Ecotones in China3.3 Classification gradesalphabet Arabic numerals as the footnote, such as"I 12,3.n;Ⅱl,2,3.n;Ⅲ1,2,3..n;…,” For example:(i)Considering differences in spatial scale and integrity of Sub-ecotone between the western mountainous forest andstructure level resulting from economic geography and grassland in Daxinanling( I 1); (iiSub-ecotone of hill-typeecosystem combined in the area, China's typical ecotones farms and grassland in the western Liaoning Provinceare classified into three levels: ecotone. sub-ecotone andunit. According to the national standards for land use3.3.3 Unitecosystem, agro-climate and landscapeThis is the evaluation unit in the zoning system. In the unit3.3.1 Ecotonethere are similar natural conditions, vegetation types, landuse and biological production potential. As well, there willThis is the highest-level division in the zoning system. be the same regularities in terms of soil erosion, processThis zone will have shared environmental characteristics, and strength. Nomenclature is as follows: the name of theecological problems, similar topography and agro-forestry vegetation types will be added to the sub-ecotone. thestructure. The zone will have the same purpose in terms marks are as follows: the identifiers like-1, -2,-3of its land resources. It will also have distinctive regional will be attached to the footnote such as I 1, 2, 3. n. Thatcharacteristics and broad distribution and will be integral is,"“I1-1,I1-2…;IIl-1,Ⅱ1-2;II1-1,Ⅲ-2….”Forand continuous in terms of spatial scales. Nomenclature example: (i) unit between the white birch broad-leavedis as follows: the economic and geographic regions forest and burnet forbs meadow in the western Daxinganlinglandscape. The marks are: Roman letters I, Il, Ill, IV. For Forest( I 1-2);(ii)unit between the highland rain fed farmexample: (i)Ecotone between forest and grassland in the and stipa grandis grassland in Bashang Grassland of Hebeinorth(I)(ii) Ecotone between farms and grassland in the Province(ll 2-1).north(Ⅲ1).3.4 Category and distribution3.3.2 Sub-ecotoneIn accordance with the professional division standards,This is the intermediate-level division in the zoning system. the indicators for national ecotone and the basicIt will have consistent basic elements such as landscape, characteristics of the fragile ecological environment,geomorphologic units, industrial structure and land use. we adopted techniques such as remote sensing, satelliteEnvironmental characteristics and hydrothermal conditions interpretation, geographic information system and graphicsare also considered within this division. Preceded by overlay to classify ecotones in China into five differentlandform assemblage, sub-ecotone, based on"Ecotone", classes, eighteen sub-ecotones and a number of units andrefers to the ecological environment in the specific produce a distribution map of national ecotones( Fig. 1)mesoscale region. The marks are as follows: Roman We classify localized ecotones if provided with regional63°00"E73°00°E83°00°E9300"E103°00°E13900"E123°00"E1300°E143°00°"E83°00°E93000"EFig. 1 Ecotone distributionmap of ChinaI Forest-steppe ecotone in North ChinaTH中国煤化工in Southwest chinaI Farming- pastoral ecotone in North ChinaCNMHGIl Desert-oasis ecotone in Northwest ChinaJournal of Resources and Ecology Vol 3 No 4, 2012vegetation types, characteristics of plant communities and of the Bashang Plateau and part of the Loess Plateau. Thisother detailed data. The classification only applies to the area can be roughly divided into the northern temperateecological transition zone in the ecosystem scaleforest-steppe ecotone and the northern warm-temperateforest-steppe ecotone4 Basic characteristics of ecotones4.1 Forest-steppe ecotone in northern China4. 1.2 Dynamic distribution of landscape pattern4.1.1 Spatial distribution characteristicsAccording to the data interpreted by TM image in 1988 and2004 we adopted a GIS spatial analysis module to create aAlthough there are different opinions within the academic landscape transfer matrix(Table 4)realm on how to best define the forest-steppe ecotone in From Table 4 we see that all landscape elements of thenorthern China, the landscape zone or vegetation zone northern forest-steppe have frequently converted betweenbetween forest and grassland with complicated structures the years of 1988 and 2004. During this sixteen year period,and obvious transitional characteristics do exist in the a total of 7858 km, the largest amount of reduction, hastemperate areas of northern China. This ecotone is located been degraded from woodland to grassland and farmlandroughly within temperate grassland west of the Northeast A total of 888.5 km, behind only that of forest, has beenPlain and eastern Inner Mongolian Plateau. This ecotone degraded from grassland to construction land or farmlandalso extends to the outer forest of Bashang Plateau, The other four landscape types have increased, the greatestbordering the eastern Loess Plateau and the western amount of which(4087. 25 km) has occurred in unusedYanshan Mountains and the western mountains of the landsteppe ecotone while the latter is known as the warm- 4. 1.3 Dynamic changes of ecological fragilitytemperate forest-steppe ecotone.With the use of ArcGiS software. natural factors humanAccording to the basic characteristics of the forest-steppe factors, economic factors and social factors were selectedecotone,we have adopted the indexes of natural climate, as key indices to evaluation ecological fragility of forestlandform and physiognomy, vegetation type and socio- steppe ecotones in China(Table 5economic to define its distribution on the basis of regional From the map we can see that ecological fragility is lessintegrity(Table 2)serious in Northeast China than in Southwest China(ig. 2).According to the indexes shown above(Table 2), the This fragility is closely related to the intense developmentdistribution of the forest-steppe ecotone is concentrated in of regional resources, population density and industrialthe semi-arid and sub-humid temperate zone of northern developmentChina(Table 3), which refers to the area among the outer From Fig 3 we can see that the ecological fragilityDaxinganling Forest, south of the Yanshan Mountain, west of the northern temperate forest-steppe ecotone hasTable 2 The main definition indexes of forest-steppe ecotone in ChinaLandform andIndexNatural climateVegetation typeSocio-economicKey indexesAnnual precipitationAltitude 600-950m Forest and grassland Husbandry revenue >30%350-500mmarea >80%Auxiliary indexes Moisture index 0.6-1.0 Lower hilly areas Steppe vegetation Coexistence of husbandry, forestry andand high plainsReference indexes Annual averagePlateauDotted with farmland Concentrated area of ethnic communitiestemperature-2.04.0℃Table 3 The type and distribution of the northern forest-steppe ecotoneMajor distribution zoneThe northen West of the northeast plains and the Daxinganling Mountain Filifoloum sibiricum and Elymus chinensis Pinus sylvestristemperateastem part of Inner Mongolia Plateau, coniferous forests, mixture in mountainous area while Stipavar. mongolicaforest-steppe the transition area between Hulunbeier of coniferous and broad- baicalensis and S grandis distributed in and elmGrassland and Daxinganling Forest leave forestsThe northen The outlying areas of forest in Bashang Quercus liaotungensis, P. S krylovii, Elymus chinensis, S. bungeana, Pinus sy/vestnisarm-highland, the eastern Loess Plateau of tabulaeformis, Populustemperate the southern Yanshan Mountains and simonii, Betula platyphylla triandraforest-steppe mountainous region of the westemYH中国煤化工 var. mongolicaCNMHGecotoneShanxi PlateauGAO Jixi, et al.: Typical Ecotones in ChinaTable 4 Conversion matrix of ILand use area in hulunbeier from 1988 to 2004 (unit: km)Landscape pattern Cultivated land Woodland Grassland Waters Construction land Unused land Total land area in 1988Arable I295.01915.024.2542.00305975(268%)56.16WoodlandABCABCABC20765052689.75128695076.756838325(609%)3.0418.8230.1832.1819.1010.68Grassland3007.2575020525652.50262.753885040585040871.503585%)7.3618.3662.760.6499343.7112.4064.1565.4070.4872.0WatersA0.250.0010.7531.505950(0.05%)B0.420.000.000.000000.00Land forA2.500.7542.751.2554.000.05%)construction8.803.704.631.3979.17C0070.000.000.197.760.02Unused land A72.2536.50532.7525.759.00871251547.50(136%B4.6934431.660.581.050.061546A6879.50605252539983.00401.75551255634.75113975.50(100%)B35.080.35D1248311.49217575219208326412Table 5 Evaluation indexes of ecological fragility of forest-steppe ecotones in ChinaIndexUnit Manifestations IndexesNatural Surface wavinessEconomical Per capita GDE10 000 CNY personfactors Abovel0'C accumulated temperature C manifestations Per capita gross industrial output value 10 000 CNY personCoefficient of atmospheric droughtsAgricultural output value ratio"Forest coverageNet income per capitaCNY personHuman Landscape fragmentation indexIlliteracy and semi illiteracy ratefactors Land reclamation rate% manifestations Engel,s CoefficientGrassland degradation rateNote: 1)surface waviness=(regional highest altitude regional lowest altitude)( national highest altitude-national lowest altitude); 2)Land reclamationrate-cultivated land/total land area; 3) Agricultural output value ratio agricultural output value/GDP.gradually increased since the 1980s, following increasing autonomous regions(banners, cities). The boundaries offragmentation. The overall ecological environment has land use have been extended frequently, growing to includebeen much more fragile with increases in population, an additional 23 000 km between 1986 and 2000deforestation, excessive reclamation and long-term over- From Figs. 4 and 5 we determine that the climaticgrazing (Lv 2007boundary of the farming-pastoral ecotone in northern4.2 Farming-pastoral ecotone in northern ChinaChina has moved towards the southeast under the impactof precipitation, temperature, evaporation and other factors4.2. 1 Spatial distribution characteristicsThe change in ranges in Northeast China, North China andWe redefined the exact location of the farming-pastoral Northwest China are greatest(maximum distance reachingecotone in northern China from the two perspectives of 2597km). The boundary of land-use in this area movesland-use and climatic elements. The results show that towards the northwest and rapid expansion can be seen inclimate changes are very obvious in the farming- pastoral the mid-western area of the northwestern boundary. Thiecotone in northern China, which covers a total area of indicates that grassland has been replaced with cultivated621 000 km, and spans over 10 in latitude and 20 in land and that中国煤化工 has been heavilyongitude. Located in 154 counties(autonomous counties damaged. TCNMH GveS towards theand county-level city), it is shared by nine provinces or northwest and sunic pan bs Ui Luc svuuicast in the farming-302Journal of Resources and Ecology Vol 3 No 4, 201220°0E1230EEcological fragility degree<-1.00010000-00-1.0000>1.0000Boundary of forest00EergunaGenheFig 3 Dynamic changes in ecological fragility of the forest-Yakeshisteppe ecotone of northern Chinaand woodland accounted for 43... 0% and 14. 4%Ewenke Qirespectively, and 41.0%33.4% and 13. 5% in the year 2000Despite this, there are no substantial changes to landscapeZhalantun4.2.3 dynamic change in ecosystem services050100200I7°0E120°0E123°0EUsing remote sensing and GIs technology we measuredthe ecosystem service value and change for the farmingFig 2 Spatial distribution map of ecological fragility in the pastoral ecotone in northern China from 1986 to 2000forest-steppe ecotone of northern ChinaResults show that the total ecosystem service value hasdecreased by 95.59 billion CNY from 1986 to 2000, or bypastoral ecotone have been transformed into purely 23.5%. For different ecosystem services, the total value ofagricultural areasfarmland, forest, shrub and grassland has been decreasing4.2.2 Dynamic changes in landscape patternsthe decreasing value of shrub has been the fastest. Howeverthe total service value of bare land and especially that ofThe spatial distribution characteristics from changes in water has been increasing. From the perspective of servicelandscape patterns in the farming-pastoral ecotone in the value per unit of different ecosystems, all have beennorth from 1986 to 2000 have been analyzed (matrix in reduced. Among them, the most dramatic decline has beenTable 6)in forest in terms of its per-unit created value, while that ofThe results show that the complex inter-conversion of water decreased fastestlandscape patterns has taken place in the farming-pastoralecotone in northern China. Most of the area is grassland4.3 Desert-oasis ecotone in northwest Chinacultivated land and woodland, accounting for 87.9% and 4.3.1 Spatial distribution characteristics88.3% of the total land area before and after the boundary The distribution region of desert-oasis ecotone in Northwestchanges, respectively. In 1986 the grassland, cultivated land China mainly includes the outer Hetao Plain, the west of1960-19701991-20001971-19802001-200Average climatic boundaryAverage climatic boundaryScale::10.00000中国煤化工0Fig. 4 The climatic boundary changes of the farming-pastoral Fig. 5 The bounCNMH Gin the farmingecotone in North chinapastoral ecotone in North ChinaGAO Jixi, et al. Typical Ecotones in China303the Helan Mountain, Hexi Corridor, the north and south structure, extremely fragile environment etc. Its area isof Tianshan Mountains, Wushaoling, Qilian Mountains, about 149 000 km, accounted for about 13. 5% of the totalAltun Mountains and the large marginal areas in the areanorth of the Kunlun Mountains. Such areas are located in 4.3.2 Evaluation of eco-environmental fragilityInner Mongolia Autonomous Region, Gansu ProvinceXinjiang Uygur Autonomous Region, Qinghai and Ningxia According to the evaluation standard(Table 8), aridity,Autonomous Region(Table 7). The desert-oasis ecotone vegetation coverage, annual precipitation, surface wavinessin China has the following characteristics: circular or and land desertification rate were used as indexes tohorseshoe shape, dominated by desert vegetation, simple conduct scientific fragility evaluation in desert oasesTable 6 Transformation matrix of landscape patterns in the farming-pastoral ecotone in northern China from 1986 to 2000Year of 2000(km)Year of 1986Cultivated Woodland Grassland Waters Construction Unused Transformed Occupancyrate(%)areaCultivated landl16533609563865753794666Woodland1408637677331413234515821446831328759144326344634062196912589343.511462432424652Construction land68021748149356251695826087Area transformed into others 90 658 46370 110 084 979232670Occupancy rate( %)41.0Total400852121580967786583Relative change rate (%)-19-58-59124.615.3Table 7 The regional characteristics and division of desert-oasis ecotone in northwest ChinaRegional characteristics CharacteristicsDesert-oasis 1. Desert landscape at oasis Agriculture industry and husbandry Desert-oasis ecotone located between Helan Mountainecotone in edgeindustry combined, with thend Ningxia and Inner Mongolia Hetao Alluvial Plainsnorthwest 2. Vegetation cover ratioChinaatter taking a larger share, water Desert-oasis ecotone located in Alluvial Plains of GansuwaterHexi Corridor3. Annual precipitationreliability ratio is rather low; Wind<200mmare rather intense, shelter g brocess Desert-oasis ecotone located in the outer Xinjiang Base4. Dryness value 4.080 Extremely low stability of the system; sensitive中国煤化工 matural recovevulnerable areaafter the vegetation has been damaged; seriousCNMH Gater erosion, more304Journal of Resources and EcVol 3 No 4Using ArcGIS we classified the vulnerability levels of theregional ecological environment(Fig. 6). The result showsthat the potentially vulnerable area, modestly fragile area,moderately fragile area, severely fragile area and extremelyfragile area among China's desert-oasis ecotone havereached394800,4521525,7194550,2622250and251 150 ha, respectively. The extremely fragile area is 44-alocated at the southern edge of the Taklamakan Desert4.3.3 Dynamic changes of ecological environmental fragilityThe desertification process has become increasinglycomplex and intensity heightened. There are more andmore areas suffering desertification and the desertificationpercentage has increased year by year. Natural vegetationPotentially fragile areaa Severely fragile areahas degraded while Aeolian landforms have developed.Duely fragile areato the short supply of water, soil becomes increasingly aridModerately fragile arearesulting in the gradual reduction of vegetation coverage Fig. 6 Fragility level distribution map of the desert-oasisand community structures. Natural disasters are often ecotone in Northwest Chinaworsened by the absence of vegetation coverageThere are more and more sandstorms and desertificationdue to the absence of vegetation cover. an instance of this4.4.2 Change analysis of landscape patternlies in information obtained from remote sensing in different Index changes at landscape level. Number of patch(NP)andperiods. One site shows fixed or semi-fixed red willow patch density(PD)continue to rise while the largest patchshrubs(shown in black and white panchromatic film) in index(Lpi) is gradually reduced and the average patch sizethe late 1950s. This same site shows mobile crescent dunes becomes smaller. This indicates that intensified landscapeand sand ridges by the late 1970s. Sandy desertification fragmentation is occurring. Interspersion and Juxtapositionslowed in the 1980s, but traces of sandy desertification are Index(IJI)and CONTAG are decreased significantly whilestill visible in data obtained from remote sensing in the two the separation index(DIVisiON) rises and the patchesbecome smaller and smaller. The connectivity of lands4.4 The Chuan-dian farming-pastoral ecotone inspace becomes less, while landscape heterogeneity increSouthwest chinaIndex changes at class level. The results show that4.4.1 Spatial distribution characteristicsthat number of patch(NP )and patch density(PD)haveThe Chuan-dian farming-pastoral ecotone in Southwest increased between 1988 and 2000 in terms of the landChina following three aspects of agro-climate, agricultural use. Interestingly, their change amplitudes are equal. Theeconomy and land-use have been defined. The results show change amplitude order is as follows: residential areathat the elevation of the ecotone ranges from 2500-2800 m shrub land>waters low-coverage grassland >medium-to 4200-4500 m, the accumulated temperature isoline above coverage grassland high-coverage grassland>unused10C ranges from 500 to 4000C, the average temperature land forestland arable land open woodland. From theof the hottest period is above 10c while the average dominant landscape types, we have compared the largesttemperature of the coldest period is above 10C. Based patch index in 1988 with the index in 2000. The patches ofon county-level administrative boundaries, the ecotone is shrub land, residential area and open woodland are muchlocated in a total of 40 county-level administrative units larger than others in terms of coverage From the standpointincluding Ganzi County, Aba County and Liangshan County of spatial separation of a variety of landscape types, thein Sichuan, Diqing County, Nujiang County and Lijiang separation rates of ten landscape types are so high that theyCounty in Yunnan, and covers an area of about 280 000 have almost reached ceiling values, indicating that patchdistribution is quite scattered. Such a phenomenon may becaused by broken terrain in the high-altitude mountainsTable 9 Dynamic changes in landscape indexes for Chuan-dian farming-pastoral ecotone in Southwest ChinaIndex of landscape patchConfiguration index of landscape spaceersitYearCONTAGDIVISIONSHDISHEI1988110150.03931.71477911中国煤化工0.7702000771960.27712.75176.73940.887CNMH0813GAO Jixi, et al.: Typical Ecotones in China3054. 4.3 Ecological fragility Assessment4.5 Eastern marine-terrestrial ecotoneEcological fragility, ecological sensitivity and ecological 4.5.I Spatial distributionelasticity are closely related to ecological pressure. The large-scale marine-terrestrial ecotone is the junctionAccording to the characteristics of the ecological between the terrestrial ecosystems and marine ecosystemenvironment of the Chuan-dian farming-pastoral ecotone located in Eastern China. It is a sensitive zone and transitionin Southwest China, we have established an ecological zone. The total length of the Chinese eastern coastline,fragility index(Table 10)comprising the main body of the marine-terrestrial ecotone,In order to facilitate horizontal and vertical comparisons is 32 000 km, of which 18 000 km is mainland coastline andbetween regions, ecological fragility is divided into five 14 000 km is island coastline. The total area of the marinedegrees from high to low: 0.81 to 1.0 for the extremely terrestrial ecotone is approximately 100 000 kImoderate fragile; 0.21 to 0.40 for the low fragile; 0 to 0.20 4.5. Dynamic change in the ecological environmentfor the general areaSea level rise: in the past 50 years Chinas coastal sea levelIn terms of spatial distribution of the ecological fragility rose at a rate of 2.5 mm per year, higher than 40% of thedegree, the extremely fragile areas and highly fragile areas rate of global sea level. In the past 30 years, the highest seaare mainly located in the eastern, western and southern parts level rise was at Tianjin at 20 cm, followed by Shanghai atof the study area. The moderate fragile areas are mainly 12 cm. Rising sea levels at Liaoning, Shandong, Zhejiangdistributed in the central region and the low fragile areas are have exceeded 10 cm, and in Fujian and Guangdong was 5-6mainly distributed in the north of the study area. The spatial cm.distribution of the ecological fragility degree has a strong Coastal retrogradation: in the past few decades sedimentcorrelation with the distribution laws of topography and supply to Chinas coasts and rivers has declined. Thegeomorphology of the study areas. The geomorphic type in general trend of the coast has changed into washout fromthe high fragile areas is high or extremely high mountains. deposit. In the coastal segments which flow over theThe geomorphic type in the low fragile areas is hilly estuary, siltation has occured, while most coastal segmentsplateau, while the geomorphic type in the moderate fragile have undergone retrogradation. The basic rule of washoutareas is almost highlands. Assessment results for ecological is that seacoast from the north of the Yangtze River estuaryfragile are shown in Fig. 7.has more obvious retrogradation than south of the estuary(Feng et al. 2006). Since 1855 average retrogradation ofthe abandoned Yellow river delta coast was 20 km, with agradation area of 1400 km (Wang 1996)Table 10 The index system of ecological fragility assessment for the Chuan-dian farming-pastoral ecotone in Southwest ChinaSub-targetStandardIndex layerIndicators WeightIndicatorsEcological Ecological 0.5 Sensitivity index for water and soil 0.6 Terrain gradient(DIll)fragility sensitivityVegetation types(D1120.3index(A) index(B1)Soil texture(D113)0.1Precipitation erosion force(D114)0.2Sensitivity index for rock0.3 Ratio of carbonate exposed outside(D121) 0.6desertification(C12)Terrain gradient(D122)Vegetation type(D123)Geological disaster index( C13)0.1 Geological disaster frequency(D131)1.0logical 0. 25 Organization index(c2 1)0.7 Vegetation coverage rate(D211)elasticityMoisture extent(D212)index(B2)≥10℃ accumulated temperature(D213)Activity index( C22)0.2 Potential biological productivity(D221)0. 1 Organic matter in soil(D231)Ecological 0.25 Population index(C31)0.3 Population density(D311)Economic development index(C32) 0.5index(B3)中国煤化工Pressure index from Resources( C33) 0.2CNMHGJournal of Resources and Ecology Vol 3 No 4, 2012ological sensitivity degreeEcological elasticity degreeEcological pressure degreecological fragility degreeLow pressure 0.21-0 40Low fragility areaLow sensitivity 0.21-0.4Low elasticityModerate pressure 0. 41-0.60Moderate fragility areaHighly sensitivity 0. 41-0.6Highly elasticitya Extremely elasticitya Highly pressure 0.61-0.80Extremely sensitivity 0.61-0.&a Highly fragility areaExtremely pressure 0.81-1.0Extremely fragility areaFig. 7 The spatial distribution of ecological fragility assessment in research area in the Chuan-dian farming-pastoralecotone in Southwest ChinaDegradation of shoals and wetlands: China's wetlands, biodiversity loss in the northern forest-steppe ecotoneincluding coasts, estuaries, rivers, lakes and swamps cover effective action is needed. This action may include250 000 km, accounting for 2.6% of national land area. strengthening regional ecological construction andWetlands in estuaries and coasts cover 50 000 km and are building a reasonable vegetation protection system andtwo extremely important ecosystems. However, in the past environmentally-friendly industrial system40 years, due to large-scale action of enclosing tideland for In the northern farming-pastoral ecotone attention shouldcultivation as the target of reclaiming land from the sea and be paid to preventing land boundaries from spreadingdeveloping shoal aquaculture, coastal areas have lost 21 900 to grasslands. This spread is due to over-grazing, over-km of shoals and wetlands, equivalent to 50% of the total cultivation and land desertification and should be avoidedarea of coastal wetlandswherever possible. In addition, more effort should beDeterioration of water quality: With the rapid directed towards the construction of ecological projects andeconomic development of coastal areas and the increasing the establishment of farming-pastoral industry structure,development and utilization of one marine-terrestrial with specific focus on the maintenance of ecologicaldeteriorated. The discharge of industrial wastewater curbed and a state ecological protective screen buil aecotone, offshore environmental quality has gradually balance. Hazards from sandstorms may be effectivelyand domestic sewage, the indiscriminate dumping of As for ecosystem deterioration caused by climategarbage, the use of fertilizers and pesticides as well as the aridification, over-exploitation of soil and water resourcesdevelopment of the mariculture have caused increasingly in the northwestern desert-oasis ecotone, the strategy ofserious offshore environmental pollution and eutrophication. determining production by water"should be implementeda Declining ability to withstand natural disasters: China's An industrial structure and development mode based onfragile zones in the coastal areas, (with ground elevation the assessment of water resources should be established inbelow 5 m are 143 900 km) account for 11. 3% of ll coastal order to recover natural vegetation. This action will help toprovince, city and district areas(excluding Taiwan, Hong maintain ecological security in the oasisKong and Macao). Among these zones, the estuary delta and In the Chuan-dian farming-pastoral zone in Southwestthe littoral plain have a vast area, generally with an altitude China, ecological environment is rather fragile and peoplebetween 15 and 4 m. These areas are vulnerable to flooding live on little economic resources. Since soil erosion hasdisasters. Due to rising sea levels, tidal backwater along the been caused mostly by human activities, including farmingcoast and rivers begins to sail upstream, influencing fresh afforestation and grazing, programs should be establishedwater supply and drinking water quality in towns along both to ensure that human activity is suited to local conditionssides of the riverAdvantage-oriented ecological industries should be5 Existing problems and countermeasuresencouraged and a mutually beneficial relationship betweenenvironment p中国煤化工 development isBased on existing problems such as excessive deforestation, requiredCNMHGa northward moving tree-line, grassland degradation and As for prorcLonugial piuuiclis such as rising seaGAO Jixi, er al. Typical Ecotones in China307levels, shrinking of mud flats and wetlands, serious coastal Kevin L and V Thomas. 2006. Climatic variability and episodic Pinuserosion, declining storage and buffering in the marineponderosa establishment along the forest-grassland ecotones of Coloradterrestrial ecotone, land use should be planned rationallyForest Ecology and Management, 228(1): 98-107and damaged ecosystems should be rebuilt by way of self Lv S H. 2007. Study on Hulun Buir forest-steppe ecotone and its ecologicalenvironmental vulnerability evaluation. Beijing: Postdoctoral Reporthealing and deliberate repair. To maintain eco-regulation Chinese Research Academy of Environmental Sciencesand coastal buffering, the management of the regional OdumEP1971(2nd ed.).Fundamentals of ecology.Pennsylvania: Saundersecology should be intensifiedWBCompanyOdum E P. 1983. Basic Ecology. Philadelphia: Saunders college PublishingReferencesRisser PG. 1995. The status of theexamining ecotones. Bioscience,lements F E. 1905. Research methods in ecology. Nebraska: University Tansley A G and T F Chipp. 1926. 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Study on biodiversity of forestboundaries:Report of a SCOPE/MAB workshop on ecotones. Biology Plant Ecology, 24(2): 141-4of Hei Bei and the east of Inner MongoliaHolland MM. 1988. SCOPE/MAB technical consultations on landscapegrassland ecotones in the northInternational, 17(Special Issue): 47-106Wang Y. 1996. China marine geography. Beijing: Science Press中国生态交错带高吉喜,吕世海?,郑志荣?,刘军会21环境保护部南京环境科学研究所,南京2100422中国环境科学研究院国家环境保护区域生态过程与功能评估重点实验室,北京100012摘要:生态交错带( Ecotone)是指两个群落或两类生态系统之间的过度带,具有脆弱、敏感和易变等特性。20世纪70年代以来,在典型生态系统研究的基础上,生态交错带逐步成为生态学研究的重点。中国地域广阃,地质、气候、植被等生态类型复杂多变,蕴育了不同类型、不同尺度和不同规模的多种生态交错带,不仅为科学研究奠定了广阔空间,而且对我国经济、社会发展,以及文化多样性保护具有重要支撑作用。本文根据我国大尺度下生态交错带的地理分布及其生态环境特点,构建了以土地利用类型、自然气候特征和农业经济发展“三位一体”指标体系,并以此为依据对中国典型生态交错带进行了划分和空间分布范围的界定;在此基础上,分别对北方森林草原交错带、北方农牧交错带、西北荒漠绿洲交错带、西南川滇衣林牧交错带和东部海陆交错带的动态变化、基本特征和存在问题进行了研究,对全面认识我国生态交错带自然演变规律,促进区域生态环境保护和优化经济发展具有重要意义。关键词:生态交错带;分类;特征;存在问题与对策中国煤化工CNMHG