封育措施对呼伦贝尔草甸草原区草地生产力的影响

目的 研究围封条件下植物群落中物种变化的分布特征，有助于解释退化草地在不同围封阶段演替规律。方法 文章以温性草甸草原为研究对象，采用野外定位随机采样方法，调查群落生物量、植物物种种类、密度、盖度及高度，探讨时间尺度封育状态下的温性草甸草原植物群落特征、物种多样性的变化。结果 （1）封育措施显著增加了群落盖度，比围栏外的自由放牧样地提高了13.79%~114.75%，且随着封育年限的增加群落盖度表现出先增加后降低；而封育措施对群落密度没有显著性影响。（2）封育显著增加了植被地上生物量、地下生物量以及禾草生物量，其中地上生物量较围栏外的自由放牧样地提高了66%~887.3%，禾草生物量和地上生物量均随着封育年限的增加表现出先增加—降低—增加—降低的波动变化，地下生物量在监测年份下表现为先增加后降低的变化；封育措施可以提升植物多样性，随着封育年限的增加，多样性指数和丰富度指数呈现先增加后降低的变化趋势。结论 封育措施可以显著提高草地生产力，并且对物种多样性也有一定的促进作用，是应对退化温性草甸草原恢复的有效措施，但退化草地在长期围封后，应进行适度利用来维持较高的生产力。

EFFECTS OF ENCLOSURE MEASURES ON GRASSLAND AND PRODUCTIVITY IN HULUNBEIER MEADOW STEPPE

This research aims to study the distribution characteristics of species changes in plant communities under enclosure conditions, which is helpful to explain the succession law of degraded grassland in different enclosure stages. In this study, the temperate meadow steppe was taken as the research object, and the field positioning random sampling method was used to investigate the community biomass, plant species, density, coverage and height, and to explore the temporal changes of plant community characteristics and species diversity in temperate meadow steppe under the time scale closure. The results showed that closure measures significantly increased the community coverage, which was 13.79 %~114.75 % higher than that of free grazing plots outside the fence, and the community coverage first increased and then decreased with the increase of closure years. But enclosure measures had no significant effect on community density. The enclosure significantly increased the aboveground biomass, underground biomass and grass biomass of vegetation, and the aboveground biomass increased by 66 % ~ 887.3 % compared with the free grazing plot outside the enclosure. The grass biomass and aboveground biomass showed a fluctuation change of increasing-decreasing-increasing-decreasing with the increase of enclosure years, and the underground biomass increased first and then decreased under the monitoring year. The enclosure measures can improve plant diversity. With the increase of enclosure years, the diversity index and richness index first increased and then decreased. This study concludes that enclosure measures can significantly improve grassland productivity and promote species diversity, which is an effective measure to deal with the restoration of degraded temperate meadow steppe. However, after long-term enclosure, degraded grassland should be moderately utilized to maintain high productivity.