Abstract:

The ecological relationship between Juglans mandshurica communities and environment was analyzed by using TWINSPAN and DCA. The results were as the following: J. mandshurica communities were classified into 7 associations by TWINSPAN, which were Assoc. Juglans mandshurica-Forsythia suspensa-Cimicifuga foetida, Assoc.Juglans mandshurica-Forsythia suspensa+Elaeagnus umbellata-Rabdosia japonica var. glaucocalyx, Assoc.Juglans mandshurica-Forsythia suspensa-Aconitum kusnezoffii, Assoc.Juglans mandshurica-Forsythia suspensa-Elsholtzia ciliate, Assoc.Juglans mandshurica-Forsythia suspensa-Carex lanceolata+Ajuga ciliate, Assoc. Juglans mandshurica-Forsythia suspensa-Saussurea davidii+Artemisia subdigitata and Assoc.Juglans mandshurica-Forsythia suspensa-Veratrum nigrum. The results of DCA ordination of 35 quadrats showed the distribution pattern of J. mandshurica communities changed with the gradient of environment factors. The first axis of the DCA ordination reflected the aspect gradient, and the second axis reflected the terrain and soil type gradient. The DCA ordination of 20 dominant species was much similar to that of 7 associations, which indicated the distribution pattern of the dominant species in the communities, to some extent, determined that of the community type. Aspect and terrain were the main factors affecting the composition and distribution of the J. mandshurica communities.

Key words: TWINSPAN classification, DCA ordination, Juglans mandshurica communities, Lishan