草地沙化度对补播地八角种群形成及优势度的影响  

Impact of Desertification Severity on Astragalus bhotanensis in Population Dynamics in Reseeding Grassland

作　　者：李佳懿 曾晓琳[1] 游明鸿[2] 刘金平[1] 杨琳雅 LI Jiayi;ZENG Xiaolin;YOU Minghong;LIU Jinping;YANG Linya(College of Life Sciences,China West Normal University,Nanchong 637009,China;Sichuan Academy of Grassland Sciences,Chengdu 611731,China)

机构地区：[1]西华师范大学生命科学学院,四川南充637009 [2]四川省草原科学研究院,四川成都611731

出　　处：《中国草地学报》2024年第8期72-79,共8页Chinese Journal of Grassland

基　　金：四川省交通运输科技项目(2019-ZL-19)。

摘　　要：依据川西草原沙化治理、草地复壮及“四库”建设的实际技术需求,以乡土豆科草种地八角(Astragalus bhotanensis)为补播物种,在4个沙化度草地(未沙化、轻度、中度和重度)补播种子后,通过测定萌发、生长及重要值等指标,研究沙化度对地八角种群形成及优势度的影响。结果表明:1)草地沙化度对地八角种群形成指标的影响大小为成苗率>出苗率>存活率>种群密度>发芽率,3个沙化度的出苗率、成苗率、存活率和种群密度均显著大于未沙化,且沙化度间差异显著(P<0.05)。2)沙化度对补播地八角优势度指标影响大小为相对密度>重要值>相对盖度>相对频度,地八角相对频度、相对盖度、相对密度随沙化度增加显著增大(P<0.05),轻、中、重度沙化的重要值是未沙化的3.56倍、10.96倍和17.26倍。3)沙化度对生长指标影响大小为株高>分枝数>根冠比>地下分配比>地上生物量>地下生物量>直立度,株高和直立度随沙化度增加显著降低,分枝数和地下生物量则呈显著增加趋势,重度沙化下根冠比和地下分配比显著大于未沙化。综上,地八角可依据草地沙化度形成相应的种群密度、优势度和株丛结构,可作为抗沙固沙乡土豆科草种在川西高原中、重度沙化草地植被修复或功能重建中推广应用。This study investigated the establishment and dominance of Astragalus bhotanensis in reseeding grasslands across varying desertification severity(non-sandy,mild,moderate,and severe desertification)within the western Sichuan Plateau.Astragalus bhotanensis,a local legume forage,was selected for its potential in grassland restoration.Population establishment metrics(germination,growth,and importance value)were assessed.The results showed the following:1)The relative impact of desertification severity on each Astragalus bhotanensis population establishment indicator was ranked as follows:seedling rate>emergence rate>survival rate>population density>germination rate.Emergence rate,seedling rate,survival rate,and population density were significantly higher in sandy grasslands compared to nondesertified areas,with significant difference observed across different levels of desertification severity(P<0.05).2)Desertification severity significantly affected the dominance index of Astragalus bhotanensis,ranked as follows:relative density>important value>relative coverage>relative frequency.The relative frequency,coverage,and density of Astragalus bhotanensis increased significantly with increasing desertification severity(P<0.05).Importancte value was significantly elevated in mildly,moderately,and severely desertified grasslands compared to non-desertified areas(3.56,10.96,and 17.26 times,respectively).3)The impacts of relative desertification on growth indicators were as follows:plant height>branching number>root to shoot ratio>belowground allocation ratio>aboveground biomass>below‑ground biomass>upright degree.Plant height and upright degree decreased with increasing desertification severity,while branching number and belowground biomass increased(P<0.05).Root to shoot ratio and belowground allocation ratio were higher in severely desertified areas.In summary,Astragalus bhotanensis exhibited strong adaptability to desertified conditions,demonstrating successful establishment and increased dominance with increasing dese

关 键 词：地八角 草地沙化 补播 优势度 抗沙固沙 

分 类 号：S812[农业科学—草业科学]