混交林的多样性及其光肩星天牛的抗性研究

Study on Diversity of Mixed Forest and Its Pest Resistance for Anoplophora glabripennis (Motschlsky)

应用DTV技术和理论 ,采用丰富度指数DMa、多样性指数H、均匀度指数JSW 及随林分中抗虫或感虫木比率由高到低变化时林分多样性指数累加值DV,分析人工混交林的多样性测度阈值与光肩星天牛危害率的关系。研究表明 ,多树种的人工混交林具有明显的抵抗蛀干害虫为害的能力 ,但混交林的抗虫力与所选配树种的抗性、抗性树种在混交林中所占的比率有关。当给定混交林分的树种数后 ,光肩星天牛的危害率PZ 与林分的多样性指数累加值DV 的关系符合Logistic模型 ;该模型中的系数a是林分本身的多样性测度值的起始位置 ,随树种数的增多a值具有稳定的增长规律 ;系数rm 的新意是混交林分对光肩星天牛扩大危害的阻力、即潜在的抗虫能力 ,rm 随林分中树种数的增多具有显著增大的趋势。林分的最大多样性测度值KDMa 、Kh、KJsw 也具有相同的变化规律。在 4～7个树种组成的系列混交林内 ,林分的多样性测度阈值DTV随树种数的增加而增高 ,但被害率极值Lvp反而降低。上述规律的意义还在于 ,随混交林中树种数的增加 ,设计或改造现有感虫林时选择树种的余地也增大。

The relation between the %DTV% (diversity threshold value) of artificial mixed forest and the percentage harm of %Anoplophora glabripennis% (Motschlsky) was analyzed by applying of the theory and technology of %DTV%, the diversity index of Margalef %D%-{Ma}, Shannon_wiener %H%, Pielon %J%-{sw} and the %D%-v of the value accumulated of diversity as the proportion of anti_pest tree species and pest infected tree' species changed from high to low. It showed that mixed forest of multiple tree species had a obviously resistance of pest damage of stem_borer, and the forest resistance ability was largely related to the pest resistance of the tree species and the percentage of the insect_resistant tree in the mixed forest. Under certain number of tree species in the mixed forest, the model of Logistic was accorded with the relation of the harm percentage %P%-z of %A. glabripennis% and %D%-v. The Logistic coefficient, α, was the starting value of the %D%-v and had a steady increase with the increased tree species; In the Logistic coefficient, the new meaning of %r%-m was that the force of resisting damage or potential pest_resistance for %A. glabripennis%, had a obviously increasing trend with, the increased tree species in the stands. Similarly, the same regularities were in maximum of %D%-{Ma}, H and %J%-{sw}. In the mixed forest for 4～7 tree species, the increase of %DTV% followed the increase of tree species in the stands, on the contrary, the point of inflection of harm percentage Lvp decreased. Another value of the regularity was that the selection range of tree species of mixed forest will increase with the tree species' increasing in anti_pest forest which was designed or reformed.