No. 910

Title:

Spatial pattern dynamics over 10 years in a conifer/broad-leaved forest, northern Japan

Author(s):

Kubota Yasuhiro/Department of Biology, Faculty of Education, Kagoshima University; Kubo Hiroyuki/Department of Biology, Faculty of Education, Kagoshima University; Shimatani Kenichiro/The Institute of Statistical Mathematics

Key words:

Abies sachalinensis; Competition; Gap dynamics; Patch mosaic; Spatial analysis

Abstract:

In the present study, we investigated stand dynamics during a 10-year period in a conifer/broad-leaved mixed forest in Hokkaido, northern Japan, focusing on spatially dependent recruitment, mortality and growth of two functional groups, conifer and broad-leaved trees. Stand-level biomass was maintained over the 10 years. Univariate and bivariate spatial analyses revealed clustering of many of the constituent species. The absence of single-species patches suggested an ambiguous mosaic characterized by a multi-species pattern. The trend towards an aggregated distribution of Abies and broad-leaved trees was caused by spatially dependent recruitment rather than mortality. Although new recruits were spatially associated with surviving broad-leaved trees for the broad-leaved species, this was not case for Abies. The degree of competitive effects on growth was not consistent over the 10-year period. Abies showed evidence of interspecific competition, while intraspecific competition were detected for no periods. In contrast, we found asymmetric competitions between the broad-leaved trees. Abies was not sufficiently competitively dominant to exclude broad-leaved trees, and a shifting mosaic pattern of the two functional groups might be maintained. The combination of weak competition between functional groups and spatially dependent regeneration dynamics plays an important role in heterogeneous patch structure of conifer and broad-leaved trees in the mixed forest.