| 摘要: |
| 【目的】研究封育和放牧管理措施对多年生草地繁殖更新的影响，为退化黄土高原植被恢复和生物多样性维持提供一定的理论依据。【方法】在云雾山草原自然保护区实验区内，选取封育23年草地和放牧地作为试验样地，采用单位面积挖掘取样法调查后代繁殖更新情况，分析比较了封育和放牧管理措施对地上植被盖度、密度、物种丰富度、多样性，后代繁殖更新密度、无性和有性繁殖密度及5种无性繁殖类型密度的影响。【结果】与放牧相比，长期封育显著降低了地上植被的密度、物种丰富度和物种多样性，而显著提高了植被盖度、枯落物厚度和枯落物生物量。黄土高原典型草原的植物更新主要以无性繁殖为主，有性繁殖为辅。其中，多年生牧草主要依靠分蘖、根茎和分枝来进行无性繁殖。与放牧地相比，封育23年草地更新苗的物种丰富度显著下降，无性繁殖密度显著降低，而有性繁殖密度差异不大。长期封育显著降低了根茎型、分蘖型和分枝型牧草的无性繁殖密度，而对根蘖型和匍匐型牧草的无性繁殖密度影响不显著。【结论】在黄土高原典型草原，是以多年生克隆植物为主的草原生态系统，地上植被的繁殖更新更依赖于无性繁殖。封育和放牧措施对多年生草地的无性繁殖影响较大。封育和放牧措施对地上植被物种多样性和密度的影响可通过植物繁殖更新进行调节。 |
| 关键词: 典型草原 有性繁殖 繁殖更新 无性繁殖 黄土高原 |
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| 基金项目:国家自然科学青年基金项目(31302013）；河南省教育厅科学技术研究重点项目(13A2302812013）；河南科技大学博士启动基金项目(09001634） |
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| Effect of grazing and grazing exclusion management on offspring recruitment in a semiarid steppe on the Loess Plateau |
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ZHAO Lingping,TAN Shitu,BAI Xin,et al
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| Abstract: |
| 【Objective】The effects of grazing and grazing exclusion management on offspring recruitment were studied to provide basis for vegetation restoration and maintaining biodiversity on the Loess Plateau.【Method】Grazing grasslands and grasslands after 23 years’ grazing exclusion in a semi-arid perennial steppe on the Loess Plateau were selected in pilot area of Yunwushan Grassland Nature Reserve.The regeneration was examined using the field root-digging method to analyze the total cover,litter thickness,litter biomass,offspring richness,and offspring numbers between asexual and sexual recruitments with five asexual recruitment types under two management types.【Result】Long-term grazing exclusion significantly reduced the density,species richness and species diversity of the above-ground vegetation,while significantly increased vegetation cover,litter thickness and litter biomass compared with grazing grasslands.The asexual offspring recruitment contributed more to vegetation regeneration than the seedling recruitment,and perennial species reproduced asexually mainly via tillers,rhizomes and root crown.Grazed sites had significantly higher species richness assessed by offspring recruitment and higher asexual recruitment numbers than grasslands with 23 years’ grazing exclusion.There were no significant differences in sexual recruitment density between grazing grasslands and grasslands with 23 years’ grazing exclusion.Grazed grassland had higher density in tiller,rhizome,and branch offspring recruitment than grasslands with 23 years’ grazing exclusion,while recruitment from root suckers and stolon was not significantly different among these two treatments.【Conclusion】Asexual recruitment played more important role in the semiarid perennial steppe,and grazing and fencing measures had greater impact on asexual recruitment than seedling recruitment.The effects of management on grassland species diversity and density could be adjusted by plant recruitment and regeneration. |
| Key words: semiarid steppe sexual recruitment offspring recruitment asexual recruitment the Loess Plateau |
