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亚洲东部与北美西部(北极和高山)冻原植物区系的联系

钱宏   

  • 收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:1993-01-10 发布日期:1993-01-10
  • 通讯作者: 钱宏

Floristic Interrelations of the Arctic and Alpine Tundras in Eastern Asia and Western North America

Qian Hong   

  • Received:1900-01-01 Revised:1900-01-01 Online:1993-01-10 Published:1993-01-10
  • Contact: Qian Hong

摘要:

 笔者分别对亚洲东北部楚科奇与北美西北部阿拉斯加(周白令海峡)北极冻原之间,亚洲东部
长白山与北美西部落基山(跨太平洋)高山冻原之间,以及亚洲东部高山冻原与其北极冻原之间和北美
西部高山冻原与其北极冻原之间的植物区系进行了对比研究。通过研究认为:(1)楚科奇与阿拉斯加
北极冻原应当区划为同一个植物区系省,即白令北极冻原植物区系省。白令北极冻原植物区系的存
在至少可以追溯到距今18000年前的更新世末次冰期。(2)长白山与落基山高山冻原植物区系之间
存在着密切的联系,它们之间有42个共有种(仅包括维管植物,以下同),其中有41种亦分布于白令
北极冻原,这种区系联系显然是在冰期通过白令陆桥来实现的。(3)长白山高山冻原与楚科奇北极冻
原之间的共有种占长白山高山冻原总种数的42%,落基山高山冻原与阿拉斯加北极冻原之间的共有种
占落基山高山冻原总种数的48.9%。  由此可见,亚洲东部和北美西部的高山冻原与北极冻原(尤其是
与白令北极冻原)植物区系之间存在着紧密的亲缘关系。

关键词: 植物区系, 北极冻原, 高山冻原, 楚科奇, 阿拉斯加, 长白山, 落基山, 亚洲东部, 北美西部

Abstract:

Tundra should be designated as the vegetation in the Arctic treeless
area beyond treeline latitudinally, and as the vegetation in alpine treeless areas
above treeline which are greatly similar to the Arctic one not only in environment
but also in floristic composition and phyto-community. Tundras are limited to the
Northern Hemisphere, and is mainly distributed in the circumpolar region (over
95% out of the total). Only a small part of tundra vegetations is scattered in the
alpine treeless areas in the middle latitudinal region of the Northern Hemisphere,
and is called the alpine tundra and/or mountain tundra. The alpine tundra is
greatly similar to the Arctic tundra not only in environment features and vegeta-
tion appearance, but in flora as well.  Actually,  nowaday alpine tundra is
directly developed from the remnant segments of the Arctic tundra which migrated
southwards to the middle latitudinal region of the Northern Hemisphere in the gla-
cial period of the last Ice-age in the Pleistocene, and later moved up to the alpine
areas in the Holocene. The alpine tundras of the Changbai Mountain and Rocky
Mountains (middle section)are located on the southern fringes of the tundras in
Eastern Asia and Western North America respectively.
    By means of comparative analyses of the vascular floras of the Chukotka (in
NE.  Asia)  Arctic  tundra  and Alaska (in  NW.  America) Arctic tundra
(transberingian comparison), the Changbai Mountain (in E. Asia) alpine tundra
and Rocky Mountains(in W.  North America)  alpine tundra( transpacific
comparison), and the alpine tundras and the arctic tundras in E. Asia and W.
North America, the results show as follows:
    (1) Because of the fact that Chukotka and Alaska not only share 411
species (making up 83% of the former total species and 72% of the latter total
species),  but  also  have many  endemic species with  a 'Chukotka-Alaska'
discontinuous distribution pattern, while there are only 268 species shared by the
Arctic tundras of Chukotka and East Siberia and 332 species shared by the Arctic
tundras of Alaska and Canada, it seems reasonable to consider the Arctic tundras
of Chukotka and Alaska as one floristic province-the Beringian Floristic
Province. The existence of the Beringian Floristic Province could at least be
traced back to 18,000 B. P. in the Pleistocene.
    (2) There is a close relationship between the alpine tundras of Eastern Asia
and Western North America. This relationship was built up by means of the
Bering Land Bridge in Ice-age.
     (3) In Eastern Asia, 42% species out of the total in the alpine tundra of
Changbai Mountains are shared with the Arctic tundra of Chukotka; and in
Western North America, 48.9% species out of the total in the alpine tundra of
Rocky Mountains (middle section) are shared with the Arctic tundra of Alaska.
Therefore, the floristic relationships of the alpine tundras and the Arctic tundras
(especially Beringian Arctic tundra) in Eastern Asia and Western North America
are very close.
     (4) The Bering Land  Bridge in the Pleistocene became an exchange
passageway of the floras between Eastern Asia and Western North America proba-
bly only for their Arctic tundra species, but not for the forest tree species nearby
the Arctic treeline.
Key words  Floristics; Arctic tundra; Alpine tundra; Chukotka; Alaska; Changbai Mountains; Rocky Mountains; Eastern Asia; Western North America