雨雪冰冻灾害对竹阔混交林植物多样性的影响

2008年雨雪冰冻灾害后,在崇义县选取了2块竹阔混交林固定样地,连续5年监测了雨雪冰冻灾害对竹阔混交林植物多样性的影响。结果表明,雨雪冰冻灾害后的5年内,林内郁闭度先减小后增大,新生毛竹数量明显增多。阔叶树种多的乔木植物层样地毛竹死亡率为9.8%,伴生树种死亡率为8.7%;伴生树种少的样地毛竹死亡率为72.0%,伴生树种死亡率为40.5%。乔木植物层物种丰富度指数、均匀度指数、生物多样性等指数变化较小。雨雪冰冻灾害后,竹阔混交林下物种种类数和物种个体数总数都增加了,但增加幅度都较小。2块样地的林下植物物种多样性指数变化幅度很小,丰富度指数和生物多样性指数增加或减少的幅度都不超1.0,均匀度指数增加或减少的幅度均不超过0.2。可见,雨雪冰冻灾害干扰后5年对竹阔混交林植物多样性影响较小,这可能与毛竹生长恢复较快有关。

Effect of Freezing Rain and Snow Disaster on the Plant Diversity of the Bamboo and Broad-leaved Mixed Forest

Mter freezing rain and snow disaster in 2008, two fixed plots were selected to measure the effect on the plant diversity of the bamboo and broad-leaved mixed forest in Chongyi County from 2008-2012 year. The result showed that the crown density reduced first and then increased within five years after the freezing rain and snow disaster. The quantity of the bamboo increased much. The mortality rate of bamboo was 9.8% ,and the mortality rate of the broad-leaved tree was 8.7% in the arbor layer of the much broad-leaved forest. The mortality rate of the bamboo was 72.0%, and the mortality rate of the broad-leaved tree was 40.5 % in the arbor layer of the less broad-leaved tree. The Margalef index, Shannon-wiener index and the Pielou index changed little in the less broad-leaved forest. The species kinds and the species number of the plant the arbor layer of diversity were in-creased under forest, but the increased extent was small. Some like sunny plant such as Diplopterygi- um chinense and Tinomiscium petiolare was appeared, and tolerant-shade plant glabra （ Thunb. ） Na- kai was disappeared, and the generation species Casuarinas equisetifolia was appeared. The changed extent of the plant diversity was little under forest during the two plots. The increased or reduced ex- tent of the Margalef index and Shannon-wiener index was less than 1. 0, and the increased or reduced extent of the Pielou index was less than O. 2. The effect of the freezing rain and snow on the plant di-versity was little in the bamboo and broad-leaved mixed forest, which might be related with the recov-ery of the bamboo.