不同恢复改良措施对退化草原羊草功能性状的影响

Effects of Different Restoration and Improvement Measures on the FunctionalTraits of Leymus chinensis in Degraded Steppe

植物功能性状能够反映植被对环境变化的响应,研究不同恢复改良措施下羊草(Leymus chinensis)功能性状,有助于解释草地生态系统中植物个体的恢复响应机制,对揭示退化草地羊草恢复机制具有重要意义。以退化羊草草原为对象,设置不同恢复改良措施与自由放牧的长期试验,通过测定株高、地上生物量、茎叶比、茎质量、茎粗、总叶面积、总叶质量、叶总长、比叶面积等9种性状指标,研究了不同恢复改良措施对羊草功能性状的影响。结果显示:(1)3种恢复改良措施显著提高了羊草植株高度、植株地上干生物量、茎叶比、茎质量、茎粗、总叶质量、叶总长(P<0.05);(2)植株高度、植株地上干生物量等9种指标均为浅耕翻(SP)和切根(CR)处理的敏感指标;除比叶面积外,植株高度、植株地上干生物量等8种指标均为围栏封育(NR)处理的敏感指标;(3)在浅耕翻(SP)和切根(CR)处理下,羊草个体生物量与植株高度、总叶面积、茎质量、茎粗均有极显著正相关关系(P<0.01),在围栏封育(NR)处理下,其个体生物量与总叶质量、茎质量、叶总长均有极显著正相关关系(P<0.01);(4)作为资源竞争力指标的植株高度,其恢复效果表现为切根(CR)>浅耕翻(SP)>围栏封育(NR),作为衡量草地生态功能和生产力的重要指标的植株地上干生物量,其恢复效果表现为切根(CR)>围栏封育(NR)>浅耕翻(SP)。从个体水平出发,综合各性状指标来看,3种恢复改良措施中切根(NR)处理对羊草恢复效果最佳。

Plant functional traits can reflect the response of vegetation to environmental changes.Studying the functional traits of Leymus chinensis under different restoration and improvement measures is helpful to explain the recovery response mechanism of individual plants in grassland ecosystem,and it is of great significance to reveal the restoration mechanism of degraded grassland.Taking the degraded steppe of Leymus chinensis as the object,three restoration measures,shallow ploughing(SP),harrowing(HA)and natural recovery(NR)were applied to the degraded steppe dominated by Leymus chinensis for nine years.Nine related traits,such as plant height,aboveground biomass,and stem to leaf ratio,stem weight stem diameter,total leaf wight,total leaf length,specific leaf area and leaf area,were measured.Results showed that:(1)three restoration and improvement measures significantly increased plant height,aboveground biomass,stem to leaf ratio,stem weight,stem diameter,total leaf wight and total leaf length of Leymus chinensis(P<0.05);(2)the nine traits were all sensitive indexes for SP,HA and NR,except specific leaf area for NR;(3)Aboveground biomass of Leymus chinensis positively correlated with plant height,leaf area,stem weight and stem diameter under SP and HA(P<0.01),but it positively correlated with total leaf wight,stem weight and total leaf length under NR(P<0.01);And(4)comparing plant height,a resource competitiveness index,the order of recovery effect was HA>SP>NR,while comparing aboveground biomass,an important indicator of grassland ecological function and production,the order of recovery effect was HA>NR>SP.In a word,HA is the most effective approach for restoration in the degraded steppe dominated by Leymus chinensis at the individual level.