Abstract: By the method of mechanical transect line, the habitat selection by Moschus moschiferus in summer in Heilongjiang Huzhong National Nature Reserve was studied from July 2005 to August 2006. Mann-Whitey U test showed that M. moschiferus favored the habitats with low tree density, low canopy density, steeper slope gradient, and high sheltering. X₂ test showed that in summer, M. moschiferus preferred to live in the conifer and broadleaf mixed forest at the mid-up slope position far away from human disturbance, close to detritus slope and water source, and of half shady and half sunny. Principal component analysis showed that the first 6 principal components, i.e., human disturbance, forest type, slope location, water source, space, and canopy density, explained 77.28% of all eigenvalues, being able to better reflect the characters of habitat.

Key words: Citrus unshiu, Light intensity, Chlorophyll fluorescence, State transition, PQ pool