围栏封育对新疆山地退化草原植物群落特征的影响

Effects of Enclosure on Plant Community Characters of Degenerated Steppe in Xinjiang

围栏封育作为一种有效的退化草原管理措施,近年来在我国退化草原恢复中得到极为广泛的应用。以新疆巴里坤县退化温性荒漠草原为研究对象,通过连续4 a围栏封育样地和自由放牧样地的植被调查资料,对比分析围栏封育样地和自由放牧样地的植被群落组成和地上生物量的动态特征。结果表明:(1)通过围栏封育措施,退化草原的物种多样性和群落生态优势度与自由放牧样地相比略有提高,群落均匀度略有降低,但通过t检验,差异均未达到显著水平(P>0.05)。(2)随着封育措施的实施,总体上草原群落优势种为沙生针茅和伊犁绢蒿,反映出西部内陆半干旱地区温性荒漠草原特有的特征;自由放牧样地,沙生针茅和伊犁绢蒿在群落中的优势地位发生变化。(3)围栏封育措施提高了植物群落的平均高度、地上生物量。随着围封时间的延长,群落地上生物量增加,且显著高于自由放牧区,然而4 a围栏封育并不能使温性荒漠草原产草量达到最高水平,也不能使植物群落的多样性指标与自由放牧样地形成显著差异。

As an effective management measure of degenerated steppe, enclosure is widely used in regenerating the degenerated steppes in recent years. The community composition and dynamic change of aboveground biomass under enclosure and uncontrolled-grazing conditions were studied during a 4-year vegetation investigation in a tem- perate desert steppe in Barkol County, Xinjiang. The results showed that the species diversity and ecological domi- nance of plant community under enclosure were slightly improved compared with those under uncontrolled-grazing conditions, but the community evenness and richness were slightly decreased although the difference between these two kinds of conditions was at significance level 〈 5 % of T-test （ P 〉 0.05 ）. The dominant species were changed by the enclosure, and they were Stipa glareosa and Artemisia spp. , which revealed the characters of the temperate desert steppe in semiarid area, west China, that means the dominant position of S. glareosa and A. spp under un- controlled-grazing conditions was changed. The average height and aboveground biomass under enclosure were im- proved. Compared with the situation under uncontrolled-grazing conditions, the aboveground biomass of plant com- munity was significantly increased with the time, but the grass yield of the temperate desert steppe could not be reached to the highest level by a 4-year enclosure, and the difference of diversity index of plant community between the enclosure and uncontrolled-grazing conditions was not significantly.