不同围封年限贵州中部暖性草丛草地的特征变化

摘要

To rationally utilize karst warm rangeland,an investigation was conducted to study the plant community characteristics in grazing areas and enclosures,and to explore the effects of different enclosing years on the basic condition of rangeland, rangeland productivity and diversity, and their correlations in central Guizhou karst warm rangeland between 2010 and 2012.Results:The constructive species in enclosing area dominated by E.kunth,E.speciosa,A.hirta,A.lanceolatus and C.cruciata were of the relative overground standing stock with an increasing trend;with the enclosing year increasing rangeland basic condition became better, continuous grazing, 1-year enclose and 2-year enclose was respectively inferior,good and excellent;For rangeland productivity,1-year enclose and 2-year enclose were significantly higher than the grazing area and the 3-year exclosures (P0.05)for the same fencing time;With the increase of rangeland condition score,rangeland productivity increased first and then decreased,and the rangeland diversity index decreased first and then increased.Short term enclosure (2 years)could increase the productivity of rangeland,long term enclosure(>2 years)was helpful for increasing the diversity of the rangeland.%为合理利用喀斯特暖性草丛草地，通过调查2010-2012年贵州中部喀斯特暖性草丛放牧与围封区草地植物群落特征，分析不同围封年限对草地基况、草地初级生产力和多样性的影响及其相关关系。结果表明：围封区以白健秆（Eulalia kunth）、金茅（Eulalia speciosa）、野古草（Arundinella hirta）、矛叶草（Arthraxon lanceolatus）和十字苔草（Carex cruciata）为主的建群种相对地上现存量呈增加趋势；随着围封年限的增加草地基况得分增加，连续放牧、围封1年和围封2年的草地基况等级分别为低劣或一般、良好和极佳；围封1年和围封2年的草地初级生产力显著高于放牧和围封3年的（P＜0．05），且围封区草地初级生产力显著高于放牧区（P＜0．05）；随围封年限的增加丰富度指数呈先增加后减少趋势，多样性指数和均匀度指数则一直增加，但3个指数在同年内围封和放牧间无显著性差异（P＞0．05）；随草地基况得分的增加，草地初级生产力呈先增加后减少趋势，而多样性指数呈先减少后增加趋势。短时间的围封（2年）有利于草地初级生产力的增加，较长时间（＞2年）的围封有利于草地多样性的增加。