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Shiro TSUYUZAKI
Plant community ecology / Environmental conservation

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

(Update on June 16 2003. Revised on January 10 2008)

Yak

Definition

Function: noun
Inflected Form(s): plural yaks also yak
Etymology: Tibetan gyagk
Date: 1795
a large long-haired wild or domesticated ox (Bos grunniens syn. B. mutus) of Tibet and adjacent elevated parts of central Asia

Yak on Ruoergai marsh

zonation Yak Yak
[Left] Landscape where vegetation zonation was surveyed. I used black/white films, becauase b/w photos were usual for publishing scientific papers.
[Center] Landscape on yak-grazing area. You can see yurts, i.e., Tibetan tents, scattered over a large area. Brown areas are becoming (semi-)bareground.
[Right] Close to yak-grazing area, we understand denudation well. The organisms laying down in the center of photo are yak, one of the cow species. So dangerous!

Effect of yak on vegetation
Fig. 1. Total or mean number of species in relation to coverage degree. Total number of species is shown by solid line, and mean number of species per quadrat is shown by interrupted lines with standard deviation drawn from vertical bar. Same letters shown above stars within circles indicate non-significant difference (t-test, p < 0.05). The difference of total number of species on cover categories is not significant (χ2 test, p < 0.05). (Tsuyuzaki & Tsujii 1990)

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References
  • Tsuyuzaki, S. & Tsujii, T. 1990. Preliminary study on grassy marshland vegetation, western part of Sichuan Province, China, in relation to yak-grazing. Ecological Research 5: 271-276
  • grazing
  • wetland (湿原)

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