Kuroda Mukai Toyohara 2006

提供: 広島大学デジタル自然史博物館 植物
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Kuroda et al. (2006b)

  • Kuroda, A., S. Mukai & G. Toyohara. 2006b. Floristic composition and community structure of dense undergrowth vegetation formed by evergreen perennial ferns, Dicranopteris linearis and Gleichenia japonica (Gleicheniaceae). Veg. Sci. 23: 25-36.


  • DOI: 10.15031/vegsci.23.25

Abstract

We investigated floristic composition and community structure of dense thickets formed by evergreen perennial ferns, Dicranopteris linearis and Gleichenia japonica (Gleicheniaceae), in a secondary forest of Miyajima Island, southwestern Japan. Vegetation samples were categorized into four stand types based on the degree of dominance of the ferns: the Dicranopteris type (DT); the Gleichenia type (GT); the non-fern-dominated type (NT) without or almost without the ferns; the intermediate type (IT) between the fern-dominated types and the non-fern-dominated type. A comparison of floristic composition among four stand types showed that few species characterized individual stand types and the four stand types were not clearly distinguished from each other in floristic composition. However, species richness in the tree, subtree, and herbaceous layers and species diversity were significantly lower in DT and GT than in NT. This can be attributed to a significant reduction in safe sites that are available for the establishment of other species due to the overwhelming predominance of D. linearis and G. japonica in the fern-dominated types. Stand type IT mostly indicated intermediate values between the fern-dominated types and the non-fern-dominated type in species richness and species diversity. The degree of reduction in light intensity under D. linearis or G. japonica canopy was comparable to that under the canopy of Sasa spp. which often prevents seedling recruitment of forest trees in cool temperate region. Analysis of the spatial dispersion pattern of fern living leaves showed that both D. linearis and G. japonica living leaves tended to be randomly distributed within their thickets as did the aerial parts of other dominant clonal plants such as Sasa palmata and Pteridium aquilinum var. latiusculum within their crowded stands. Overall, the results obtained in this study suggested that D. linearis and G. japonica thickets possessed a high competitive ability over other colonizers. Some consideration was added regarding ecological roles of D. linearis and G. japonica thickets in terms of rehabilitation and conservation of disturbed forest ecosystem.