高原鼢鼠对高寒草甸植被特征及生产力的影响

本研究结果表明，高原鼢鼠栖息10年的斑块，植物群落的物种数减少，植物物种多样性指数下降，地上、地下总生物量显降低，单子叶和可利用双子叶植物生物量极显减少，但不可利用双子叶植物生物量显增加。高原鼢鼠去除5年后，斑块内植物群落的单子叶植物物种数增加，而双子叶植物下降，植物群落物种多样性指数下降，地上、地下总生物量显增加，单子叶和可利用双子叶植物生物量增加极显，不可利用双子叶植物生物量显降低。高原鼢鼠栖息10年的斑块，净初级生产量较未栖息地区减少68.98%。高原鼢鼠去除5年后，净初级生产量增加，但仅达到未栖息地区的58.69%。

EFFECT OF PLATEAU ZOKORS ON VEGETATION CHARACTERISTICS AND PRODUCTIVITY OF ALPINE MEADOW

This research was conducted on alpine meadow site at Menyuan county, Qinghai Province, People's Republic of China to determine the effects of native, subterranean rodent of Qinghai Tibet grasslands, the plateau zokors ( Myospalax baileyi ), on seasonal above and below ground plant biomass, plant species diversity and productivity Both total peaks of above and below ground biomass were the greatest (413 600 g/m 2 and 2 297 502 g/m 2 ) in the patch no any plateau zokors colonized and least(170 200 g/m 2 , 489 110 g/m 2 ) in the patch colonized by plateau zokors over 10 years in August and October, respectively Both above and below ground biomass were significantly increased in the patches where plateau zokors were removed or the burrow systems were abandoned for five years compared to the patches plateau zokors colonized over 10 years However, both above and below ground biomass in abandoned patches were significantly lower than that in uncolonized patches Monocotyledonous biomass was reduced greatly, but the non palatable dicots were significantly increased in colonized patches The palatable biomass of monocots and dicots were increased in abandoned patches Total plant species diversity was the greatest in uncolonized patchesand least in abandoned patch The total net primary production in colonized patches was reduced by 68 98% compared with uncolonized patches Although the patches were without any plateau zokors disturbance for fives years, the total net primary production just reached 58 69% of the uncolonized patches The above ground net primary production in abandoned patches increased 28 74% and the below ground increased 54 91% compared with the colonized patches We suggest that plateau zokor induced changes in plant above and below ground biomass and species diversity may lead to further alterations of nutrient cycling and trophic dynamics in this alpine meadow ecosystem