林周河谷高寒草甸和灌丛草场可饲用天然牧草时空变化特征
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摘要
为研究西藏"一江两河"流域高山草甸和灌丛草场的时空变化特征,在牧草发青季(2017年7月份)、丰草季(2017年9月份)和枯草季(2018年3月份),对不同海拔梯度林周河谷南山阴坡和北山阳坡草地进行调查分析。结果表明:(1)林周河谷南山阴坡低海拔处以白草为优势种,海拔升高100 m左右时出现灌丛植被类型;山坡中段为草甸草场,主要以高山嵩草和苔草为主。总盖度最高月份为7—9月,随海拔升高,盖度相应增加,不同季节同一海拔高度总盖度间均差异不显著(P>0.05),而不同海拔高度、同一季节中总盖度差异极显著(P<0.01)。(2)季节显著影响牧草含水率(P<0.01),可饲用牧草含水率7—9月份最高,10月份后随牧草枯萎而下降,进入冬季降至0%;同一季节不同海拔梯度中,低海拔和中段海拔可饲用牧草中含水率较高。(3)不同季节可饲用牧草的产草量间差异极显著(P<0.01),单位面积总可饲用牧草产草量10月末最高,夏秋季最低;随海拔高度升高,可饲用牧草的产草量显著增高(P<0.05)。(4)经三维响应曲线拟合,总盖度y、海拔梯度x_1、月份x_2之间的关系为:y=a_1+a_2×x_2~2+a_3×x_1+a_4×x_2(a_1,a_2,a_3,a_4分别为-657.137 4、-0.882 8、0.167 1、12.507 0);含水率y、海拔梯度x1、月份x2的关系为:y=a_1+a_2×x_2~2+a_3×x_1+a_4×x_2(a_1,a_2,a_3,a_4分别为-146.147 1、-3.883 9、-0.010 0、62.100 6);产草量y、海拔梯度x1、月份x2的关系为:y=a_1+a_2×x_2~2+a_3×x_1+a_4×x_2(a_1,a_2,a_3,a_4分别为-131.065 5、2.977 2、0.069 0、-36.511 1)。结论:通过研究,建立了林周河谷南山阴坡主要高山草甸放牧草场的总盖度、含水率与产草量的立体时空变化特征;北山阳坡主要为高山灌丛,非天然放牧场所,作为饲用牧场,研究意义不大。
To study the spatial-temporal variations of alpine meadow and shrub grassland in "One River and Two Streams"in Tibet,forage and vegetation in July,September and March along different altitude of south-shade slope and north-sunny slope in Linzhou river valley were investigated in this article. The results showed as follows:(1)the grassland was dominated by Pennisetum centrasiaticum Tzvel in the low altitude south-shade slope,then there shrub appeared as the altitude elevation of 100 meter. The grassland in middle slope was meadow,mainly distributed Kobresia pygmaea and Carex spp. The highest vegetation coverage was found in July and September,and it increased as the altitude increased. There was no significant difference in coverage between different seasons at the same altitude(P >0.05),while the significant difference existed between different altitudes in the same season(P<0.01).(2)Forage water content was significantly affected by season(P<0.01);it was the highest one during July-September,decreased in October,and was 0% in winter. The water content in forage in the low and mid-altitude was higher than that in the high-altitude and shrub grassland.(3)There was significant difference in forage yield between different seasons(P<0.01). The highest forage yield per ha was at the end of October,the lowest one was in summer and autumn. Forage yield significantly increased as the altitude increased(P<0.05).(4)The response curve analysis indicated three equations that included y(coverage,water content,and forage yield),altitude x_1,and month x_2. They were:ycoverage=a_1+a_2×x_2~2+a_3×x_1+a_4×x_2(a_1,a_2,a_3,a_4 was -657.137 4,-0.882 8,0.167 1 and 12.507 0,respectively);ywater content=a_1+a_2×x_2~2+a3×x_1+a_4×x_2(a_1,a_2,a_3,a_4 was-146.147 1,-3.883 9,-0.010 0 and 62.100 6,respectively);yforage yield= a_1+a_2×x_2~2+a_3×x_1+a_4×x_2(a_1,a_2,a_3,a_4 was -131.065 5,2.977 2,0.069 0 and-36.511 1,respectively). The natural forage variations of total vegetation coverage,moisture content and forage yield were researched with spatial-temporal in north-shady slope of south mountain on alpine meadow.However,it was shrub grassland in south-sunny slope of north mountain but wasn't important grazing land to research.
To study the spatial-temporal variations of alpine meadow and shrub grassland in "One River and Two Streams"in Tibet,forage and vegetation in July,September and March along different altitude of south-shade slope and north-sunny slope in Linzhou river valley were investigated in this article. The results showed as follows:(1)the grassland was dominated by Pennisetum centrasiaticum Tzvel in the low altitude south-shade slope,then there shrub appeared as the altitude elevation of 100 meter. The grassland in middle slope was meadow,mainly distributed Kobresia pygmaea and Carex spp. The highest vegetation coverage was found in July and September,and it increased as the altitude increased. There was no significant difference in coverage between different seasons at the same altitude(P >0.05),while the significant difference existed between different altitudes in the same season(P<0.01).(2)Forage water content was significantly affected by season(P<0.01);it was the highest one during July-September,decreased in October,and was 0% in winter. The water content in forage in the low and mid-altitude was higher than that in the high-altitude and shrub grassland.(3)There was significant difference in forage yield between different seasons(P<0.01). The highest forage yield per ha was at the end of October,the lowest one was in summer and autumn. Forage yield significantly increased as the altitude increased(P<0.05).(4)The response curve analysis indicated three equations that included y(coverage,water content,and forage yield),altitude x_1,and month x_2. They were:ycoverage=a_1+a_2×x_2~2+a_3×x_1+a_4×x_2(a_1,a_2,a_3,a_4 was -657.137 4,-0.882 8,0.167 1 and 12.507 0,respectively);ywater content=a_1+a_2×x_2~2+a3×x_1+a_4×x_2(a_1,a_2,a_3,a_4 was-146.147 1,-3.883 9,-0.010 0 and 62.100 6,respectively);yforage yield= a_1+a_2×x_2~2+a_3×x_1+a_4×x_2(a_1,a_2,a_3,a_4 was -131.065 5,2.977 2,0.069 0 and-36.511 1,respectively). The natural forage variations of total vegetation coverage,moisture content and forage yield were researched with spatial-temporal in north-shady slope of south mountain on alpine meadow.However,it was shrub grassland in south-sunny slope of north mountain but wasn't important grazing land to research.
引文
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[7]段敏杰,高清竹,郭亚奇,等.藏北高寒草地植物群落物种多样性沿海拔梯度的分布格局[J].草业科学,2011,28(10):1845-1850.
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[10]郑伟,李世雄,董全民,等.放牧方式对环青海湖高寒草原群落特征的影响[J].草地学报,2013,21(5):869-874.
[11]孙宗玖,朱进忠,张鲜花.短期放牧强度对昭苏草甸草原植被特征及多样性影响[J].新疆农业大学学报,2014,37(1):35-39.
[12] Badano E I,Marquet P A,Cavieres L A. Predicting effects of ecosystem engineering on species richness along primary productivity gradients[J]. Acta Oecologica,2010,36(1):46-54.
[2]西藏自治区统计局. 2017西藏统计年鉴[M].北京:中国统计出版社,2017:6.
[3]罗黎鸣,苗彦军,武建双,等.拉萨河谷同地灌丛草地物种多样性随海拔升高的变化特征[J].草业学报,2014,23(6):320-326.
[4]任继周.草业科学研究方法[M].北京:中国农业出版社,1998.
[5]马红梅,拉穷.拉萨河谷天然草地空间异质性研究——以林周县白草草原为例[J].西藏大学学报(自然科学版),2017,32(1):7-16.
[6]王长庭,王启基,龙瑞军,等.高寒草甸群落植物多样性和初级生产力沿海拔梯度变化的研究[J].植物生态学报,2004,28(2):240-245.
[7]段敏杰,高清竹,郭亚奇,等.藏北高寒草地植物群落物种多样性沿海拔梯度的分布格局[J].草业科学,2011,28(10):1845-1850.
[8]魏克家,李海萍,王学江,等.青海高原草甸草场类型特点及利用改良[J]. 2002(2):1-17.
[9]郑晓翾,靳甜甜,木丽芬,等.呼伦贝尔草原物种多样性与生物量、环境因子的关系[J].中国草地学报,2008,30(6):74-81.
[10]郑伟,李世雄,董全民,等.放牧方式对环青海湖高寒草原群落特征的影响[J].草地学报,2013,21(5):869-874.
[11]孙宗玖,朱进忠,张鲜花.短期放牧强度对昭苏草甸草原植被特征及多样性影响[J].新疆农业大学学报,2014,37(1):35-39.
[12] Badano E I,Marquet P A,Cavieres L A. Predicting effects of ecosystem engineering on species richness along primary productivity gradients[J]. Acta Oecologica,2010,36(1):46-54.