东北红豆杉种群的回归成效及影响因素

Reintroducing effects and influencing factors of Taxus cuspidata population

【目的】回归是一种濒危物种保护与种群恢复的重要方法。本研究以极小种群物种东北红豆杉为研究对象,选择3种不同的林型以及两组不同苗龄的东北红豆杉幼苗开展野外回归试验,研究适宜东北红豆杉回归林型以及回归过程中幼苗生长及存活的主要影响因素,以期为东北红豆杉回归保护提供科学依据。【方法】选择杨桦林、红松云冷杉林和红松紫椴林3种林型作为回归试验地,以1~2年生和4~5年生东北红豆杉实生幼苗作为试验材料,移栽后调查土壤因子、地形因子等指标,逐月调查幼苗存活率、苗高、地径、冠幅等指标。对幼苗各生长指标进行差异性显著分析和多重比较,通过灰色关联分析等方法研究回归幼苗生长过程中的影响因子。【结果】东北红豆杉回归幼苗当年存活率达86%以上,地径、苗高、冠幅均有所增长,除1~2年生东北红豆杉幼苗苗高生长量外,各林型中东北红豆杉幼苗生长指标生长量均无显著差异,红松紫椴林的1~2年生东北红豆杉幼苗苗高生长量显著高于杨桦林和红松云冷杉林。由于越冬期间,4~5年生东北红豆杉幼苗受到狍啃食,存活率显著下降且长势极差;1~2年生幼苗受长时间的低温胁迫生长状况也受到一定影响。东北红豆杉回归幼苗的存活和生长受到多种环境因子的影响,关联度最大的是林型,其次是坡向、坡度和郁闭度,土壤化学性质指标的关联度较小。【结论】4~5年生幼苗因受动物啃食而回归效果不良;1~2年生幼苗适应杨桦林、红松云冷杉林和红松紫椴林下这3种生境,回归最适宜的林型是红松紫椴林;林型、坡向、坡度、光照是影响东北红豆杉回归的主要环境因子。

[Objective]Reintroduction is an important method for endangered species conservation and population restoration.Taking Taxus cuspidata,a critically endangered wild plant with extremely small population,as the research object,this study chose three different forest types and two groups of different age T.cuspidata seedlings for field reintroduction tests,studied the reintroducted forest type suitable for T.cuspidate and the main factors influencing seedling growth and survival during reintroduction process.It is hopefully to provide scientific evidence for the conservation of T.cuspidata.[Method]Betula platyphylla-Populus cathayana forest,Pinus koraiensis-spruce-fir forest and P.koraiensis-Tilia amurensis forest were selected as the reintroduction experimental forest types,indexes such as soil factors and topographic factors were investigated,and indexes such as seedling livability,seedling height,basal diameter and crown breadth were investigated monthly.Difference significance analysis and multiple comparison were conducted for each growth index of seedlings,and the influencing factors of reintroducted seedling growth were studied through grey correlation analysis and other methods.[Result]The very year survival rate of reintroducted seedlings of T.cuspidata was more than 86%.The ground diameter,seedling height and crown width all increased,except for the seedling height growth of T.cuspidata in 1-2 years,the growth indexes of T.cuspidata seedlings of all forest types showed no significant variations.The 1-2 years old T.cuspidata seedlings of P.koraiensis-T.amurensis forest were significantly higher than that of B.platyphylla-P.cathayana forest and P.koraiensis-spruce-fir forest.As it was during the overwintering period,4-5 years old T.cuspidata seedlings were eaten by roe deer,their survival rate decreased significantly,and the growth rate was very poor;the growth of 1-2 years old seedlings was also affected to some extent by long-term low temperature stress.The survival and growth of reintroducted seedlings of T.cuspidata were affected by diversified environmental factors,among which,the most relevant was forest type,followed by slope aspect,slope degree and canopy density,while the association degree of soil chemical property index was less.[Conclusion]The effect of reintroduction of 4-5 years old T.cuspidata seedlings is poor due to predation of animals.1-2 years old seedlings adapt to the three habitats of B.platyphylla-P.cathayana forest,P.koraiensis-spruce-fir forest and P.koraiensis-T.amurensis forest,and the optimum forest type for the seedling reintroduction of 1-2 years old is P.koraiensis-T.amurensis forest.Forest type,slope aspect,slope degree and light are the primary environmental factors influencing the reintroduction of T.cuspidata.