【作者】 单贵莲；

【导师】 徐柱；

【作者基本信息】 中国农业科学院 ， 草业科学， 2009， 博士

【摘要】 为揭示典型草原恢复演替过程中健康诸因子的变化规律,丰富草地生态系统健康评价内容,促进草地生态系统健康评价指标体系的发展,本研究以内蒙古锡林郭勒典型草原为研究对象,选取2002年围封(围封6～7年,F02)、1999年围封(围封9～10年,F99)、1996年围封(围封12～13年,F96)、1989年围封(围封19～20年,F89)的生长季围封恢复草地为研究对象,同时选取自由放牧草地(未围封,F0)为对照,开展典型草原恢复演替过程中植被与土壤特征的比较研究,分析典型草原恢复演替过程中健康诸因子的变化规律。在此基础上,筛选典型草原生态系统健康评价的敏感指标,构建草地生态系统健康评价指标体系,并对不同围封年限典型草原的健康状况和服务价值做出评价。主要研究结果如下:(1)放牧草地采用生长季围封的管理措施后,草地恢复演替,草地产草量、群落盖度、密度、地下生物量、地表凋落物增加,且随围封年限的延长,草地产草量、群落盖度、密度、地下生物量、地表凋落物显著增加,但若围封后连续多年割草利用,容易导致草地发生二次逆行演替,因此围封19～20年草地的产草量、盖度、密度、地下生物量、地表凋落物再次下降。(2)放牧草地采用生长季围封恢复措施后,土壤0～10cm、10～20cm土层中粗沙(2.00～0.25 mm)含量显著降低,细沙(0.25～0.05mm)和粉粘粒(<0.05mm)含量显著增加,土壤容重和紧实度降低,土壤孔隙度、养分含量、微生物数量、微生物生物量碳、氮含量增加,土壤酶活性增强。且随围封年限的延长,土壤孔隙度、土壤养分、微生物数量、微生物生物量及酶活性呈增加的变化趋势,围封12年土壤质量最好。但由于围封后连续多年割草利用,导致围封19年土壤质量下降。(3)从生态系统结构与功能入手,构建出典型草原健康评价的指标体系,并进一步筛选出典型草原健康评价的敏感指标包括草地产草量、群落盖度、地表凋落物、优良牧草比例、牧草粗蛋白、土壤紧实度、土壤有机质、土壤微生物量氮8项定量指标以及优势物种组成和生活型层片构成2项定性指标作为典型草原健康评价指标。(4)采用灰色关联分析、模糊综合评价、VOR和CVOR指数模型四种评价方法对不同围封年限典型草原的健康进行了评价,评价结果一致,说明四种方法均可作为典型草原健康评价方法。另外,健康评价结果表明:自由放牧草地由于连续多年重度放牧利用,草地退化演替,草地健康状况下降至“警戒”;采用生长季围封措施后,草地恢复演替,围封6～7年,草地恢复演替至“亚健康”,围封9～10年,草地健康状况逐渐由“亚健康”向“健康”过渡;围封12～13年,草地恢复演替至“健康”状况;但若围封后连续多年割草利用,草地容易发生二次逆行演替,因此围封19～20年草地健康状况再次向“亚健康”过渡。(5)放牧草地采用生长季围封恢复措施后,草地的服务价值明显提高。与自由放牧草地相比,围封6～7年、9～10年、12～13年、19～20年典型草原单位面积草地提供的服务价值分别提高17.64%、29.11%、53.62%、39.87%。说明季节性围封是维护草地生态系统服务价值,实现草地畜牧业可持续发展的有效途径。更多还原

【Abstract】 To disclose the variation law of health factors of typical steppe in restoring process, expand the content of grassland ecosystem health evaluation, promote the development of grassland ecosystem health evaluation, we chose typical steppe in Xinlingol League as research area, and selected the natural grassland which were exclosured in different years, including the sites exclosed in 2002 (exclosued for 6 to 7 years, F02) , exclosed in 1999 (exclosued for 9 to 10 years, F99) , exclosed in 1996 (exclosued for 12 to 13 years, F96) , exclosed in 1989 (exclosued for 19 to 20 years, F89) as research objects, at the same time, selected free grazing grassland as control (all treats set two times repeated), carried out the comparative research on vegetation and soil characteristics and analyzed the variation law of health factors of typical steppe in restoring process. Based on this, we constructed the index systems of grassland ecosystem health evaluation, elected the sensitive indices of typical steppe health evaluation, and evaluated the health status and the service value of typical steppe in different exclosure period. The main results are as follows:(1) The degraded typical steppe developed positively, the production, coverage, density, under-ground biomass and litter biomass of the grassland increased and the structure of community optimized after the utilization of seasonal exclosure. Along with the prolonging of exclosure period, the production, coverage, density, under-ground biomass and litter biomass increased significantly, but if hay production was developed continuously for many years, and then the grassland might appear the second retrogressive succession, so the production, coverage, density, under-ground biomass and litter biomass of the grassland decreased again after exclosed for 19 to 20 years.(2)After the utilization of seasonal exclosure, the proportion of coarse sand (2.00～0.25 mm) dropped significantly, and the proportion of fine sand (0.25～0.05mm) and silt and clay (<0.05mm) increased significantly, soil bulk density and compaction dropped, soil porosity, nutrient and microbe quantity increased, soil microbial biomass and enzyme activity enhanced in the layer of 0～10cm and 10～20cm.And soil porosity, nutrient, microbe quantity, microbial biomass and enzyme activity showed the trend of rise along with the increase of exclosure period, and after exclosed for 12 year, the quality of the soil reached to the best. But the soil quality descended again after enclosed for 19 year because of the mowing utilization for many years.(3)Started with the ecosystem structure and function, constructed the index system of grassland ecosystem health evaluation. And selected eight quantitative and two qualitative indices, including the production, community coverage, litter biomass, excellent forage proportion, forage crude protein, soil compaction, soil organic matter, soil microbial biomass nitrogen and dominance species and life form synusia composition, as the sensitive indices of typical steppe health evaluation.(4)The health condition of typical steppe in different exclosure period was evaluated by grey correlation analysis, fuzzy comprehensive evaluation, VOR index and CVOR index, the result showed that all of the methods used above could be used to evaluate the health condition of typical steppe. In addition, the result showed that the health condition rose after the utilization of seasonal exclosure. In free grazing land, the health condition decreased to“threshold”because of continuous heavy grazing, after the utilization of seasonal exclosure, the health condition was significantly increased. So the health condition of typical steppe increased to“sub-health”after exclosued for 6～10 year, and then increased to“health”condition after exclosued for 12～13 year. But the health condition of typical steppe descended to“sub-health”again after exclosued for 19～20 years, analyzing the reason was continuous mowing for many years.(5)After the utilization of seasonal exclosure, the service value of typical steppe was significantly increased. Compared with free grazing land, the total value of service function of typical steppe was increased by 17.64%, 29.11%, 53.62% and 39.87% respectively after exclosing for 6～7, 9～10, 12～13 and 19～20 years. Showed that seasonal exclosure was the effective method for maintaining the service value of grassland ecosystem and realizing the sustainable development of grassland animal husbandry.更多还原