Wetland Birds And Their Habitats Importance Evaluation In Dunhuang West Lake Area

In order to found out the bird situation of the west lake area in Dunhuang,and provide scientific data for the management of the wetlands in decision-making.The author first investigated species and quantity of the birds and their habitat conditions of 18 wetlands in the territory of the west lake area from spring of 2007 to spring of 2008.And the following three major studies were completed:(1) landscape structure of the wetlands;(2) diversity of the birds in the west lake area;(3) importance evaluation of the wetland bird habitats.Among them,the first study refined the basic landscape composition,with field observations of the internal landscape characterization of the wetlands,and the result will be displayed in diagram;in the second study,Direct Counting and No Distance Estimate Line Transect methods were used to investigate the species and quantity of the birds.Avifauna Analysis Method and Community Measure Index were used to research bird diversity;the third study was carried out by using the Fuzzy Comprehensive Evaluation Method.The following major findings and conclusions are draw from the studies:(1) Landscapes within the wetlands are divided into 5 large patches:freshwater meadow swamp, reed swamp,salt marsh,saline and alkaline land,shrub and forest belt.And two types of landscape structural model are brought forward:one is belt-shape landscape and the other is ring-shape landscape. The wetland bird habitats are divided into 8 types:freshwater meadow swamp,the water area of reed swamp,open water of salt marsh,mud flat,shrub and forest,open water of reservoir,highly salinity salt marsh,reed community.And among them,four kinds of habitats enjoy higher species richness and similarities,they are mud flat,the water area of reed swamp,open water of salt marsh and open water of reservoir.Open water of salt marsh or open water of reservoir,with the water area of reed swamp and mud flat altogether form a functional complementary combination of the best habitat.(2) There are a total of 119 kinds of birds investigated within the territory,classified to 16 orders, 36 families,73 genus.In which,one kind is Chinese endemic species,it is White-tailed Growd-Jay (Podoces biddulphi),and 6 species are new records for GanSu Province,they are Red-necked Grebe (Podiceps grisegena),Greater Scaup(Aythya marila),Long-tailed Duck(Clangula hyemalis),Ruff (Philomachus pugnax),White-tailed Growd-Jay,Black-legged Kittiwake(Rissa tridactyla).68 kinds of birds are listed as protected species,accounting for 57.1%of the total number.In which,one kind belongs to PROTⅠ,it is Black Stork(Ciconia nigra),18 species belong to PROTⅡ,they are Eurasian Spoonbill(Platalea leucorodia),Whooper Swan(Cygnus Cygnus) etc,one kind enters excursusⅠof CITES(2007) which is Peregrine Falcon(Falco peregrinus),and 16 species enter excursusⅡof CITES, including Osprey(Pandion haliaetus),Saker Falcon(Falco cherrug) and so on,9 species are written into RDB,srch as Black-tailed Godwit(Limosa limosa) etc,47 kinds are listed as migrators protection convention between China and Japan,and 17 kinds are listed as migrators protection convention between China and Australia.The number of bird species in the west lake area is about 1/4 of that in Gansu Province,accounting for 87.5%of that in Hexi Corridor Geographic Province with high species richness.(3) The duck family(Anatidae) includes 21 species,which constitutes the largest number in all the families;followed by eagle family(Accipitridae) and thrush family(Turdidae),each of which has eight species;plover family(Charadriidae) and snipe family(Scolopacidae),each of which has seven species; the families which has only one species come to a total of 15,which account for 41.7%of the total family numbers.(4) The F index of the birds in the west lake area is 16.14,while G index is 4.10,and the G-F index is 0.75.And among them,the duck family makes the largest contribution to the F index value and the duck genus(Anas) plays the largest role for the G index value.(5) In this area,palaearctic species and holarctic species are the main ingredients,which together account for 74.79%,followed by middle asian species.Inhabitation pattern based mainly on passing birds,and there are 66 species;seven kinds of migratory birds in winter;26 kinds of resident birds,and 32 kinds of migratory birds in summer.(6) Of all the 107 species within the 18 wetlands,77 species out of 3595 birds distribute in spring, and 65 species out of 1203 birds distribute in autumn.70.1%of the birds belong to narrow distributions; 4 species are wide distributions,they are Mallard(Anas platyrhynchos),Ruddy Shelduck(Tadorna ferruginea),Common Shelduck(Tadorna tadorna) and Red-crested Pochard(Rhodonessa rufina).The majority of birds mainly distribute in seven wetlands.Wowachi has the most species and quantity,and its Shannon-Wiener index value is the highest.Another five wetlands retain better bird conditions and higher diversity,they are Yangshui Lake,Nanda Lake,Beiyuan Lake,Hecang City and Xiaoma Mitu. Status of the birds of Yanchi Sinus wetland enjoys a higher level,but lower level of diversity.Spring Shannon-Wiener index value is higher than that in autumn for all wetlands except for the New Dam.(7) Birds which individual magnitude between 1～4 occupy the larger parts,there are 29 species in spring and 34 species in autumn.With a higher degree of magnitude,such birds mostly have 1 or 2 species each.The distribution of the number of the birds focuses on a small range of types.The largest number of birds in spring is Black-winged Stilt(Himantopus himantopus),of which 73.1%individuals gathered around Yanchi Sinus wetland.There are a large number of Tufted Duck(Aythya fuligula), Red-crested Pochard,Eurasian Wigeon(Anas penelope) etc;the largest number of Mallard appeared in autumn,with a total number of 382.Followed by Common Coot(Fulica atra) with the number of 70, also similar to the number of Great Egret(Egretta alba),Bearded Parrotbill(Panurus biarmicus) ect.(8) Birds in the west lake area belong to 6 major eco-groups,they are swimming bird,songbird, wading bird,birds of prey,climbing bird,terrestrial bird,of which swimming bird is the most type with 41 species;followed by songbird with 36 species.Swimming bird mainly distributed in open water of salt marsh and open water of reservoir,and some distributed in the high salinity salt marsh;wading bird mainly located in the mud flats and water areas of reed swamp;birds of prey have a wider scope of activities;the other 3 groups are mainly distributed in another 3 types of habitats which are freshwater meadow swamp,shrub and forest,reed community.(9) According to the results of fuzzy comprehensive evaluation,two management programs are brought forward:one is to devote the same level of management inputs in both spring and autumn,and then further break down management in spring and autumn in accordance with their sorting and classification results respectively;the other is to an give overall classification management to wetlands in the two seasons,based on the the importance of the distinction between every wetlands in the two seasons.Based on the first program,the wetlands with importance value from 0.2 to 1 are devoted into first-grade management level,which include Woguichi,Yangshui Lake,Yanchi Sinus and Nanda Lake, the wetlands with importance value from 0 to 0.2 are devoted into second-grade management level which include Danghe Reservoir,Dunzi Sinus,Nanyuan Lake and Majuan Sinus in spring.Based on the first-grade management level,Woguichi,with importance value from 0.4 to 1,is further devoted into hypo-first-grade management level,and Yangshui Lake,Yanchi Sinus and Nanda Lake,with importance value from 0.2 to 0.4,are devoted into hypo-second-grade management level.The wetlands of second-grade management levels can be broken down according to their ordering results.And the level classification in autumn can be similar as that in spring.Based on the second program,the wetlands with importance value from 0.4 to 1 are devoted into first-grade management level,which only include Woguichi wetland of both spring and autumn,and the level put into Woguichi in spring will be more than that in autumn.The wetlands with importance value from 0 to 0.4 are devoted into second-grade management level,which include all the wetlands except Woguichi.Based on the second-grade management level the wetlands with importance value from 0.2 to 0.4 are devoted into hypo-first-grade management level,which include Yanchi Sinus,Yangshui Lake and Nanda Lake of sping,and Yangshui Lake of autumn,the wetlands with importance value from 0 to 0.2 are devoted into hypo-second-grade management level,which include Danghe Reservoir,Dunzi Sinus,Nanyuan Lake and Majuan Sinus of spring,and Danghe Reservoir,Yanchi Sinus,Dunzi Sinus, Nanyuan Lake,Nanda Lake and Majuan Sinus of autumn.The wetlands of hypo-second-grade management levels can be broken down according to their ordering results.