不同放牧方式下防除黄帚橐吾对高寒草地植物群落的影响

合理的放牧方式是青藏高原高寒草地可持续利用的前提。本研究通过监测牧、自由放牧+药物防除(牧+防，G+C)、牧草生长季禁牧(禁，E)和牧草生长季禁牧+药物防除(禁+防，E+C)4种草地管理措施对黄帚橐吾(Ligularia virgaurea)型退化草地的群落特征和产草量的影响发现：牧+防和禁+防显著降低黄帚橐吾地上生物量和密度(P<0.05)；植物群落地上生物量和高度在禁和禁+防处理下显著高于其他处理(P<0.05)，且在牧+防和禁+防处理下，植物群落的优势种由黄帚橐吾+垂穗披碱草变为高原早熟禾，而牧和禁处理下，植物优势种在3年内均为黄帚橐吾；只有放牧处理下物种多样性在年份间变化显著(P <0.05)；牧+防和禁+防处理下，禾本科地上生物量占比显著增加(P <0.05)，而黄帚橐吾地上生物量占比显著减少(P <0.05)。综上所述，牧+防和禁+防均可显著抑制黄帚橐吾生长，而禁+防显著提高禾本科牧草的产量。因此，禁+防是橐吾型退化草地恢复改善的适宜管理措施。

Effects of Ligularia virgaurea Control on Plant Community of Grassland under Different Grazing Modes

Reasonable grazing is required for sustainable utilization of alpine grassland. In this study,four grassland management methods were adopted(grazing (G),grazing+control of Ligularia virgaurea (G+C),enclosed grazing in pasture growing season (E),and enclosed grazing in pasture growing season+control of Ligularia virgaurea (E+C) in the growing season). The community characteristics and grass yield of Ligularia virgaurea degraded grassland were monitored. The results showed that:1) the aboveground biomass and density of Ligularia virgaurea were significantly reduced by G+C and E+C (P<0.05);The total aboveground biomass and height of plant community under E and E+C treatments were significantly higher than those of other treatments (P<0.05),and under G+C and E+C treatments,the plant community successively from Ligularia virgaurea+Elymus nutans to Poa alpigena,while under G and E treatments,the dominant species were Ligularia virgaurea within 3 years;Species diversity varied significantly in 3 years only under G treatment (P<0.05);The proportion of aboveground biomass of Gramineae increased significantly under the treatment of G+C and E+C(P<0.05),while Ligularia virgaurea decreased significantly (P<0.05). To sum up,the two treatments of G+C and E+C can significantly inhibit the growth of Ligularia virgaurea,and E+C can significantly increase the yield of Gramineae. Therefore,E+C is an appropriate management measure for restoration and quality improvement of Ligularia virgaurea degraded grassland.