Study on β biological diversity dynamic change of Larix gmelinii forests after fire disturbance

By using the methods of time instead of space, researched on the forest in the burned areas which burned by middle intensity fire after different years and unburned areas which seemed to be contrast samples, both of them were in Daxing'an Mountains. The results showed that: after the highintensity fire disturbance, the community average Jaccard similarity coefficient of the highest security for the Rhododendron-Larix gmelinii forests (0.5439), Grass-Larix gmelinii (0.4772) minimum, that the Rhododendron-Larix gmelinii forests'high-intensity fire disturbance on the diversity of β security Larch of impact was minimal, while the Grass-Larix gmelinii is the greatest impact; in low-intensity fire and middle-intensity fire disturbance on Larix gmelinii forests cluster β diversity the most. Based on the Cody index, the high-intensity fire on the Grass-Larix gmelinii, higher than the rate of change of species, the low-intensity fire disturbance, and the middle-intensity fire disturbance on species of Rhododendron-Larix gmelinii forests, rate of change the greatest impact. After that fire disturbance, greatly improved the wet habitats, conducive to the increase in community diversity, and dry habitats on the maintenance of community diversity has more advantages.