影响大兴安岭火烧迹地干部害虫发生的生态因子

Ecological Factors Affecting the Occurrence of the Stem-Infesting Insects in the Burnt Areas of Daxing'anling Mountain

“五·六”特大森林火灾后,以云杉小黑天牛Monochamus sutor L.、落叶松八齿小蠢Ips subelongatus Motsch为先锋及优势种的50余种干部害虫先后侵入火烧林分.林分的感虫株率与火烧程度、透光度以及林分中衰弱木、枯立木的数量呈正相关;不同林型干部害虫群落组成及感虫株率有明显差异;人为活动能加剧或控制其发生与为害;各种干部害虫种群数量的急剧增加,引起了对食物资源和营养空间的竞争,导致本代生育率降低,子代成活率下降;随干部害虫种群数量的剧增,其天敌种群数量也迅速增殖,对干部害虫起到了明显的控制作用。

The serious destruction of a forest's ecological environment by forest fires is suitable for outbreaks of stem-infesting insects. Ips subelongatus, Monochamus sutor as the dominant species and more than 50 other species of stem-infesting insects have attacked burnt stands within three years of the fire. The ratio of attacked trees of burnt stands, related to the intensity and density of burnt canopy plus the number of weak and dead trees(or dying trees). The species composition of the pests and the ratio of attacked trees are different, dependant on the type of forest stand.The occurrence and damage of stem-infesting insects can be aggravated or controlled by man's action. The population quantity increase of a variety of stem-infesting insects must cause interspecific and intraspecific competition for food resources and nutrient spaces. This then results in a decrease of reproduction capacity in the parent generation and an increase in mortality of the next generation. As the species and quantity of steminfesting insects increas, so too does the variety and quantity of their predators. More than 50 species of predators and parasites have been found. It has been shown that these natural enemy have an important inhibitting role on the stem-infesting insects in burnt area of Daxing'anling Mountains burnt area, stem-infesting insects, burnt intensity, forest types, canopy density, natural enemy, r-strategy