摘要
调查研究了德钦县高寒灌草甸所承受的人为干扰状况及其后果。结果表明,干扰体中牲畜放牧是澜沧江流域亚高山草甸生态系统中干扰强度最大、频率最高、干扰时间最长、影响后果最严重的人为干扰。过去14年来放牧干扰强度明显增强,牲畜种群数量增加了8.51%,尤其是牦牛(犏牛)增加了16.79%,对草甸生态系统的压力愈来愈大,给德钦草地带来了严重的后果。草场利用面积14年来虽然增加了约15%,但草地总可食生物量却下降了1.7%。其中,高山灌草甸可食生物量分别下降了28.4%和21.9%,亚高山地段的林间草地、疏林草地、亚高山灌丛草地分别下降了12.6%、17.2%和6.9%,生态系统生产力退化明显。草场整体呈退化趋势,局部退化已经相当严重。长期过牧已经导致了一些退化指示植物如鸢尾、橐吾、高山大戟在德钦县形成占优势的群落类型,虽增加了德钦草甸群落的多样性,但降低了草地物种的多样性,引起了德钦畜牧业产品的减少,导致近年来德钦县肉、奶等畜牧产品产量明显下降,严重限制了德钦草地畜牧业系统的持续发展。
This study was conducted in Deqin county of north_western Yunnan,an important yak_raising area in China, and focused on the past 14 years development of man_made disturbance on alpine and sub_alpine meadow.Several conclusions had been made.Livestock grazing is the dominant disturbance with the strongest intensity,the highest frequency,the longest action time and with the most serious after_effects on meadow.Livestock heads increased by 8.51% from 1986 to 1998,especially Yak population increased by 16.79%,but the population of goat/sheep declined by 29%.Another apparent change is the horse population, which has increased over 124% owing to the boom of tourism in the last decade.The increasingly livestock population brought stronger pressure to alpine meadow ecosystem. The area of open pasturelands changed from 178280 km2 in 1986 to 205942 km2 in 1999,an estimated 15% increase.The major expansion of grazing lands mainly occurred in the subalpine belt.Compared to 1986,edible biomass of alpine meadow and alpine scrub_meadow declined 28.4% and 21.9% respectively in 1999.Not considering the enlargement of area in subalpine grazing land,the edible biomass of pastures among forests,thinning woodland_pasture and subalpine scrubs respectively decreased 12.6%,17.2% and 6.9%,respectively,from 1986 to 1999.All displayed meadow productivity had declined and meadow ecosystem degraded seriously.An important finding is that the long_term high_intensive grazing increased community diversity but decreased species diversity in a community.Most community types were on the degrading way and obvious interactive substitution was found among these communities.Iris japonica community,Actium lappa community,and Stellera chamaejasme community were the most typical and poisonous types formed under the seriously degradated of meadows.Since 1993,the output of meat and other products decreased.The output rate of livestock in CU(cattle unit)was only 2.5% in 1986 and 1.2% in 1998.All those restrained the sustainable development of animal husbandry.
出处
《中国草地》
CSCD
2003年第2期1-8,共8页
Grassland of China
基金
国家基础规划发展研究项目(G199804814)
中国科学院知识创新工程项目(KSCX1-07-01-01)
中国科学院"九五"重大项目(KZ951-A1-104)
国家知识创新工程西南基地项目共同资助
关键词
高山亚高山草甸
人为干扰
可食生产力
过度放牧
草场退化
Alpine and sub-alpine meadow
Humen disturbance
Overgrazing
Pasture degradation
Edible biomass
