Abstract: Based on the daily precipitation observation data of 11 meteorological stations from 1971 to 2015 in Inner Mongolia Daxing’anling forest region, the linear regression, inverse distance weighted (IDW) interpolation and Morlet wavelet analysis method were employed to analyze the spatiotemporal dynamics of precipitation days and intensity at different grades in Daxing’anling forest region, Inner Mongolia. The results showed that: (1) Lightrain days showed a decreasing trend, while the variation trends of moderate and heavyrain days were not obvious. The variation trend in annual precipitation intensity at each grade was not significant. The fluctuation of heavyrain intensity tended to be gentle after 2000. (2) The average contribution rate of precipitation at different grades was in the order of heavy rain>moderaterain>light rain. (3) Different grades of precipitation intensity showed different periodic variation patterns on different time scales. The lightrain showed periodic variations on 7, 13, 19, 27 a, moderaterain on 22 and 10 a, and heavy rain on 25 and 7 a. (4) Spatially, moderaterain days, heavyrain days and precipitation intensity at all levels showed a gradual increase trend from the west to the east, while lightrain days showed an opposite pattern. (5) There was no significant difference in spatial variation of annual precipitation in Daxing’anling forest region. The results can provide basic reference for forestry and agricultural production in this region.

Key words: interspecific association, dominant species, niche breadth, niche overlap