蒙古高原中蒙毗邻针茅草原放牧生态学比较研究
Comparative Study on Grazing Ecology in Stipa Steppe between China and Mongolia of Mongolian Platean

中国内蒙古和蒙古国共同占据着蒙古高原主体部分。由于各种因素的干扰,中蒙两国草原生态环境已存在不同程度的退化。目前对蒙古高原草原放牧生态学系统对比研究尚未见报道。因此本论文对中蒙两国毗邻针茅草原不同放牧样地进行对比研究;研究内容包括植被群落多样性、植物功能群特征、主要植物营养特性、土壤种子库特征、表层土壤理化特性及草地健康评价等。以期探寻不同放牧方式的生态学差异,为蒙古高原草原生态环境保护和合理利用提供理论依据。主要研究结果如下:1.植被群落多样性对比研究表明,群落多样性指数和丰富度指数表现为四季游牧(FSNG)>两季轮牧(TSRG)>四季轮牧(FSRG)>定居放牧(SG),而均匀度指数与多样性指数相反。主要多年生植物重要值为蒙古四季游牧高于其它放牧样地;一年生植物重要值低于其它放牧样地。群落多样性指数间相关分析表明,多样性指数、优势度指数与丰富度指数间均呈正相关,多样性指数、丰富度指数与均匀度指数间呈负相关。群落相似性系数结果显示,典型和荒漠草原FSNG与SG间相似性系数为0.416、0.571,典型草原FSNG与TSRG间相似系数为0.836,相似性明显高于定居放牧。总体结果表明蒙古四季游牧和内蒙古两季轮牧植被群落多样性显著高于内蒙古定居放牧。2.植物功能群多样性分析结果显示,内蒙古定居放牧样地多年生草本比例显著或极显著低于其它放牧样地,旱生植物比例显著高于其它放牧样地。蒙古四季游牧样地多年生群落平均重要值高于内蒙古样地,一年生群落平均重要值低于内蒙古样地。在多年生和一年生群落中,蒙古四季游牧样地多年生草本植物比例高于内蒙古样地,一年生草本植物比例低于内蒙古样地。蒙古四季游牧样地功能群多样性指数和优势度指数高于内蒙古样地,均匀度指数与多样性指数相反。功能群多样性间相关分析结果表明,多样性指数与优势度指数间呈显著正相关(r>0.855,P<0.05);均匀度与多样性指数、优势度指数间均呈负相关。功能群生态位分析表明,多年生和一年生草本植物、旱生和中旱生植物的生态位宽度均较大,从而多年生与一年生植物间、旱生与中旱生植物间生态位重叠值相应较大。建群种植被评价结果表明,蒙古四季游牧草地为轻度退化(4级),内蒙古四季轮牧和两季轮牧草地为中度退化(3级),内蒙古定居放牧草地为极度退化(1级)。总体结果表明蒙古四季游牧和内蒙古两季轮牧植物功能群多样性较高。3.植物营养成分分析结果表明,典型草原四季游牧样地磷、钾含量显著高于内蒙古样地,FSNG和TSRG的氮、可溶性糖含量显著高于FSRG和SG样地。荒漠草原四季游牧样地氮、磷、钾和可溶性糖含量均高于内蒙古样地,其中钾含量存在显著差异(P<0.05);说明典型草原样地间差异大于荒漠草原样地。蒙古四季游牧样地主要多年生植物营养含量显著或极显著高于内蒙古样地,一年生植物营养含量显著或极显著低于内蒙古放牧样地。四季游牧样地光合色素平均含量高于内蒙古样地,并差异不明显。蒙古四季游牧样地主要多年生植物光合色素含量显著或极显著高于其它样地,一年生植物光合色素含量显著或极显著低于其它放牧样地。植物营养与光合色素含量间相关分析表明,营养与光合色素间均呈正相关,其中磷、糖与光合色素间相关性比氮、钾的相关性高。植物营养含量重要值评价结果表明,蒙古四季游牧样地植物营养重要值为“中等”(4级),内蒙古两季轮牧为“稍缺”(3级),内蒙古四季轮牧和定居样地为“缺”(2级)。总体结果表明蒙古四季游牧植物营养水平高于内蒙古放牧样地。4.土壤种子库物种多样性研究表明,蒙古四季游牧多样性指数、丰富度指数和优势度指数均高于内蒙古放牧样地,而均匀度指数低于内蒙古放牧样地。典型草原种子库物种数和密度为FSNG>TSRG>FSRG>SG;荒漠草原为FSNG>SG;总体结果为蒙古四季游牧土壤种子库密度显著或极显著高于内蒙古放牧样地。两种草原土壤种子库物种均呈现一年生多于多年生植物,双子叶多于单子叶植物。土壤种子库物种相似性分析结果表明,典型草原四季游牧与两季轮牧间相似性较高,与其它放牧样地间相似性较低;荒漠草原四季游牧与定居放牧样地间相似性也较低。土壤种子库与地上植被物种相似性分析结果显示,内蒙古定居放牧样地相似性指数最高,蒙古四季游牧样地为最低;说明内蒙古定居放牧样地草地生产更新能力较低,草原退化较严重。土壤种子库特征评价结果显示蒙古四季游牧样地为轻度退化(4级),内蒙古两季轮牧样地为中度退化(3级),内蒙古四季轮牧样地为重度退化(2级),内蒙古定居样地为极度退化(1级)。5.土壤特性研究表明,蒙古四季游牧样地和内蒙古两季轮牧样地除砂土、pH值和全钾含量低于内蒙古四季轮牧和定居样地外,其它性状均高于内蒙古四季轮牧和定居样地,其中典型草原差异大于荒漠草原。土壤理化特性间相关分析表明,土壤理化各要素间存在一定相关性。土壤与群落特征相关分析表明,群落特征与砂土、砂壤土、pH及全钾间基本呈负相关,与土壤其它特性间存在正相关关系。植物营养与土壤特性间相关分析表明,植物营养与土壤pH间,可溶性糖与土壤全钾间呈负相关外,与土壤其它特性间基本存在正相关关系。群落多样性指数与土壤特性间相关分析表明,群落多样性指数与砂土、pH及全钾间呈负相关外,与其它土壤特性间存在正相关关系。土壤理化成分重要值评价表明,蒙古四季游牧样地为未退化(5级),内蒙古两季轮牧样地为轻度退化(4级),内蒙古四季轮牧样地为重度退化(2级),内蒙古定居样地为极度退化(1级)。表明内蒙古放牧样地土壤退化较严重。

community characteristics showed that there was negative correlation between community characteristics and arenaceous land, arenaceous soil, pH kalium, and positive correlation between community characteristics and other chemical characteristics. Correlation between plant nutrient and soil characteristics showed that there was negative correlation between plant nutrient and pH, soluble sugar and soil kalium.Correlative analysis between Shannon-wiener index and soil characteristics showed that there was negative correlation between Shannon-wiener index and arenaceous land, pH, kalium, while it positive correlation between Shannon-wiener and other soil characteristics. Evaluation of soil characteristics showed that grassland at FSNG was not degraded(5th level), grassland at TSRG was light degradation(4th level), grassland at FSRG was sever degradation(2nd level), grassland at SG was extreme degradation(lst level).6. The study of health evaluation feld the aim and effect of production performant evaluation is unequal to ecological evaluation. The former mainly serve animal husba-ndry and pay attention to productivity differences. The latter evaluation mainly evaluate ecological function and degradation degree.Evaluation contents includs native vegetation,plant nutrient,soil seed bank,soil characteristics.We established a simple ecological evaluation and emphasized differences between grassland situatuation and native vegetation, so as to comprehensively evaluate ecological performance.7. Evaluation of production performance showed that grassland at FSNG and TSRG was moderate degradation (3rd level), grassland at FSRG was severe degradatin (2nd level), grassland at SG was extreme degradation (lst level). Our result showed that production performance between SG and FSNG, TSRG was very significant difference.8. Comprehensive evaluation of ecology showed that grassland at FSNG was light degradation (4th level), grassland at FSRG and TSRG was moderate degradation (3rd level), grassland at SG was extreme degradation (lst level). The result was basically equal to vegetation evaluation, we recommend to apply vegetation evaluation in order to simplify evaluation and facilitate production application in grassland evaluation.

Mongolian plateau; Stipa steppe; Grazing system; Vegetation and Soil characteristics; Health evaluation;

易津;

S812

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