不同坡向高寒草甸群落结构和生物量分异特征

EFFECT OF DIFFERENT SLOPES ASPECT ON ALPINE MEADOW PI ANT COMMUNITY AND BIOMASS

以玉树市典型高寒草甸为对象,分析了阳坡坡下部、坡脚,半阴坡坡下部、坡脚,阴坡坡下部、坡上部的高山嵩草、异针茅草甸(KP-SA)、西藏嵩草草甸(KT)、珠芽蓼草甸(PV)、圆穗蓼草甸(PC)、矮生嵩草草甸(KH)、高山嵩草、圆穗蓼草甸(KP)六种草地类型形态指标和地上生物量变化。结果表明,KP样地的群落平均株高最大,为19.33cm,显著高于KT、PV、KH和PC样地(P<0.05)。PV样地的物种数最大,为18.67种/m^(2),与KP样地无显著差异,而显著高于其余样地(P<0.05)。KP样地的牧草鲜质量、可食牧草鲜质量、牧草干质量和可食牧草干质量均为最大值,分别为454、412.33、136.2和123.7g/m^(2),均显著高于其余样地(P<0.05),较KH样地分别显著增加1.29倍、1.40倍、1.29倍和1.40倍(P<0.05)。高寒草甸海拔、植被盖度、群落平均株高与高寒草甸牧草鲜质量、可食牧草鲜质量、牧草干质量和可食牧草干质量呈显著相关(P<0.05)。可见,阴坡更利于高寒草甸植被生长,不仅生物量高,物种也更多,在进行轮牧、休牧时,可适当调整单位载畜量和缩减休牧时间。

The paper analysised the changes of morphological indicators and aboveground biomass about KP-SA(Kobresia pygmaea Stipa aliena),KT(Kobresia tibetica),PV(Polygonum viviparum),PC(Polygonum capitatum),KH(Kobresia humilis)and KP(obresia pygmaea)alpine meadow sample on the toe,lower of south-facing slope,west-facing slpoe and the lower,top of north-facing in the yushu alpine meadow.the results showed that the average plant height of KP sample,which was 19.33 cm every square meter was significantly heigher than KT,PV,KH and PC samples(P<0.05).The species was 18.67species/m^(2)of PV sample,which was significantly higher than other samples except KP sample(P<0.05).The plant aboveground fresh weight,dominated plant aboveground fresh weight,plant aboveground dry weight and dominated plant dry weight of KP sample were 454,412.33,136.2and 123.7 g/m^(2),which were significantly increased 1.29 times,1.40 times,1.29 times and 1.40 times than KH sample(P<0.05),respectively.Altitude,coverage,average plant height had significantly correlation with the plant aboveground fresh weight,dominated plant aboveground fresh weight,plant aboveground dry weight and dominated plant dry weight(P<0.05).These resluts showed northe-facing slope was benefical to growth of alpien meadow.It was useful for increasing grazing capacity or reducing rest grazing time when rotational grazing or rest grazing.