Microtopography and distribution of canopy trees in a subtropical evergreen broad‐leaved forest in the northern part of Okinawa Island, Japan

Abstract

The spatial distribution of trees in relation to topography was investigated using two topographic indices, slope steepness and slope configuration, in a 4‐ha plot in a subtropical evergreen forest in the northern part of Okinawa Island, Japan. Most species showed an aggregated distribution and patch size was related to various microtopographical features, including small ridges and valleys. In a cluster analysis based on the dissimilarity of each species’ distribution, the species were divided into three major clusters. A significant correlation between the dissimilarity and the distance between each species on the axis of the two topographic indices indicated that species association was, in part, explained by the topographic indices. I suggest that species distributed on steep and concave slopes regenerate depending on disturbances such as landslides on unstable topography, whereas species distributed on ridges and upper slopes regenerate depending on the canopy gap. A number of species that were less abundant in the 4‐ha plot occurred in the riparian area near a stream, where the density of more abundant species was low. The results of this study support the existence of habitat niche divergence related to topography in a subtropical evergreen broad‐leaved forest.

Spatial Heterogeneity in Tree Diversity and Forest Structure of Evergreen Broadleaf Forests in Southern China along an Altitudinal Gradient

“…Wolf et al argued that aspect and slope have a considerable effect on tree species diversity, because they determine water availability [54]. Enoki found that the diversity of plant species distributed on concave and convex slopes have significant differences [55]. However, Legendre et al found that the effects of slope and aspect on distribution of richness and species composition are weak [56], similar to our results.…”

Wind-based Dispersal of Oribatid Mites (Acari: Oribatida) in A Subtropical Forest in Japan

“…The bedrock is composed of sandstone and slate, and the forest soil is classified as a yellow soil (Y) according to the classification methods of forest soils in Japan (Morisada, 1999). This forest is dominated by Castanopsis sieboldii with a maximum height of less than 20 m. There is no history of logging or other artificial disturbance in this area during the past 50 years (Enoki, 2003).…”

Caracterização silvigênica de um trecho de floresta Ombrófila densa do parque estadual Carlos Botelho, Sete Barras - SP

“…Os fatores edáficos, topográficos, climáticos e biológicos são os principais responsáveis pelas quedas das árvores e conseqüente abertura de clareiras (BROKAW, 1985;HALLE et al, 1978;OLDEMAN, 1974a;Oliveira-Filho et al, 1994ROBERT, 2003) e podem tornar-se mais relevantes em áreas de declividade acentuada.A topografia é considerada por alguns autores (ENOKI, 2003;LOSOS, 2004;OLIVEIRA-FILHO et al, 1994) como um dos fatores abióticos que mais influencia na estrutura de florestas tropicais em escala local, por estar fortemente correlacionada a outras variáveis ambientais, como a presença de água no solo e as características físico-químicas dos solos.…”