Available online at www.sciencedirect.com Progress in Natural Science 18 (2008) 833–841 www.elsevier.com/locate/pnsc The boundary of palaearctic and oriental realms in western China Ling Chen a,b,c, Yanling Song d,*, Shufang Xu e a Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810001, China b Graduate University of the Chinese Academy of Sciences, Beijing 100039, China c National Science Foundation of China, Beijing 100085, China d Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China e Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China Received 13 December 2007; received in revised form 1 February 2008; accepted 2 February 2008 Abstract In the world-wide zoogeographic division, there has been no consentaneous understanding about the delimitation between palaearctic and oriental realms in western China. In this study, we will discuss the division based on amphibian distribution in Shaanxi, Gansu, Sichuan, Yunnan, and Tibet according to species coefficient similarity between each zoogeographic province. The results show that the northern border lies from Qinling Mountains–Feng Xian (Shaanxi)–Debu (Gansu)–Aba (Sichuan)–Batang–Bomi (Tibet), to Linzhi districts, and the southern border is from Taibai–Feng Xian in Shaanxi–Wen Xian (Gansu)–Songpan–Kangding–Daocheng (Sichuan), to Zhongdian–Gongshan in Yunnan, and westward to Motuo and Bomi district in Tibet. Ó 2008 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved. Keywords: Amphibian; Zoogeography; Palaearctic; Oriental; Hengduan Mt. 1. Introduction In general, the boundary between the two realms in the eastern part of China to the east of Qinling Mountains is China covers the oriental and palaearctic zoogeographic coinciding with the 0 °C isotherm of the average tempera- realms [1–6]. On the issue of the boundary between the two ture in January and with the 800 mm isohyet line yearly. zoogeographic realms in China, there is an agreement in Geographically, it is the border of the subtropical and tem- eastern part of China [4,6]. However, for the border in west perate zones, as well as the border of the south and the China, from Qinling Mountains to Himalayan area, no north of China. In the west of China the border is consid- agreement has been obtained. Due to the complicated land- ered as the boundary of subtropical zone and the plateau. form and climate, fauna of palaearctic and oriental realms However, there is argument on locations of the boundary mixed up in the Hengduan Mt. region between Qinling and in specific regions or for specific species [8] due to the Himalayas in a broad transition. The geographic location, locally special landform and climate. For example, there as well as the south–north direction of the Hengduan Mt., are different opinions on which area should be included provides traveling channels in the valleys to animals. in the oriental realm in Gansu province [9–11]. Therefore, the animal component belonging to either orien- Efforts have been made to resolve this problem. Chen et al. tal or palaearctic realm is penetrative and interlaced in this discussed the eastern circumscription in the Tibet plateau region on a large scope [7]. geographic zone based on the fish distribution data and the geographical events there [12]. Hoffmann proposed a broad * Corresponding author. Tel.: +86 10 64807127. transition zone in China and adjacent countries as the south- E-mail address: [email protected] (Y. Song). ern circumscription of the palaearctic realm by analyzing the 1002-0071/$ - see front matter Ó 2008 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved. doi:10.1016/j.pnsc.2008.02.004 834 L. Chen et al. / Progress in Natural Science 18 (2008) 833–841 data of mammalian faunas in those nations [13]. His conclu- issue of palaearctic and oriental realms. The amphibians sion is different from traditional conception and has been in the west districts are listed in Fig. 1 and Table 1. queried by biogeographic researchers of China [14]. The determination of zoogeographical division, espe- 2.2. Methods cially on the specific boundary, depends on the distribution of animals to be discussed. Mammals and birds, due to their We analyzed the components and the distribution pattern high adaptation to environment diversity and higher loco- of amphibians in each zoogeographic province based on the motion ability, are not appropriate to discuss the division zoogeographic division of amphibian in west China [15]. For issue generally. However, the amphibian, as cold-blooded a given zoogeographic province, if it only contains species to animals, need both aqueous and terrene environment to one realm (either oriental or palaearctic), it is regarded as the accomplish their life history and their distribution range is specific realm. If it contains species that occurs in the two limited by water and heat. This feature makes them a better realms and is located between the subtropical and warm indicator to discuss the definite zoogeographic division zones or plateau, it is regarded as the permeation district of compared with mammals and birds. In this study, we use the two realms. In addition, we calculated the coefficient of amphibians as an objective to explore the zoogeographic similarity between each zoogeographic province concerned division of palaearctic and oriental realms in west China. to discuss the relation of amphibians with those adjacent provinces. The coefficient of similarity basically reflects the 2. Materials and methods genetic relationship and diversities of different zoogeo- graphic provinces. The more identical the species compo- 2.1. Materials nents of the two regions are, the closer they are in geology and evolution [22]. Comparing the similarity of one district All the amphibian distribution data used in this study to the others, we can affirm the relationship of every zoogeo- are from published literatures [9,15–21]. We only consider graphic province, and then draw the validated border of pal- those zoogeographical regions related to the boundary aearctic and oriental in western China. Similarity coefficient (S) is calculated by S ¼ð2n=ðN 1 þ N 2ÞÞ%: Here, n is the number of identical species in both A and B regions, N1 is the number of species in region A, N2 is the number of species in region B [23]. We consider the rela- tionship of two given provinces with a coefficient (S) value. The similarity is considered to be low for S < 0.4, general for 0.4 6 S < 0.6, significant for 0.6 6 S < 0.8, and very significant for S P 0.8, respectively. 3. Results and analyses For convenience in discussion we simplified the diagram to show the relative location of zoogeographic division in administrative provinces concerned in western China (Fig. 1). Each square represents a specific zoogeographic province and the number in each square is the total species Fig. 1. Distribution diagram of amphibians in west China. (A) Southern recorded there. The name list of amphibians in western China Qinling hilly province; (B) northern Qinling hilly province; (C) loess is given in Table 1, and the matrix of coefficient similarity plateau province; (D) desert province of northern Shaanxi; (E) southern Longnan hilly province; (F) northern Longnan hilly province; (G) central between zoogeographic provinces is provided in Table 2. loess plateau province of Gansu; (H) loess plateau province of Longdong; (I) Gansu corridor province; (J) Qilian Mt. province; (K) Gannan plateau 3.1. Shaanxi and grassland province; (L) northwestern Sichuan plateau province; (M) western basin province; (N) Daba province northeast of Sichuan basin; Shaanxi is divided into four zoogeographical provinces (O) central basin province; (P) southeastern basin province; (Q) south- western plateau province of Sichuan; (R) Hengduan high mountain gorge (Fig. 1), i.e. southern Qinling hilly province (A), northern province northwest of Yunnan; (S) high mountain and gorge province Qinling hilly province (B), loess plateau province (C), and northern and northeastern of Yunnan; (T) southeast mountainous desert province of northern Shaanxi (D). The northern province; (U) plateau of central and east Yunnan; (V) western mountain- Qinling hilly province includes actually the region along ous province of Yunnan; (V1) tropic mountainous province southern both sides of the major ridge. Traditionally, the southern Yunnan; (W) Sanjiang Hengduan province; (X) Cha-yu province south- east of Tibet; (Y) Himalayas province; (Z) valley province of southern side of the ridge was regarded as the south circumscription Tibet; (Z1) Fioeld-mark province of Qiang-Tang. *Species number of this province. It is also believed to be the boundary of undetermined. south and north China, as well as the south border of L. Chen et al. / Progress in Natural Science 18 (2008) 833–841 835 Table 1 The amphibian species and distribution in western China (1, exist; blank, absent) Species A B C G K F E L M N OQRWXYZ Batrachuperus karlschmidti Liu 1 Batrachuperus pinchonii (David) 1 1 1 1 1 Batrachuperus tibetanus Schmidt 1 1 1 1 1 1 1 1 1 1 Batrachuperus yenyuanensis Liu 1 Liua shihi (Liu) 1 1 Ranodon tsinpaensis Liu and Hu 1 1 Andrias davidianus (Blanchard) 1 1 1 1 1 1 1 1 Echinotriton asperrimus (Unterstein) 1 1 Tylototriton taliangensis Liu 11 Tylototriton verrucosus Anderson 1 Bombina maxima (Boulenger) 1 1 Atympanophrys