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

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

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。

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.