鳥取県岩美町唐川湿原の自然環境 : 地形・地質と植生

The Karakawa moor situated in the mountainous area of eastern part of Tottori Prefecture west Japan was investigated geologically and vegetationaty as the basic study for conservation of natural environments. The 26 hand orger drillings revealed the buried topography under the moor. There are small ridge and two shallow valleys under the moor. The formation of moor was promoted by deposition of dam upped sediments at the junction of these two valleys, The sediments are composed of gravel, silt and clay, volcanic ash and black organic soil (peat) in ascending order. The volcanic ash is considered as secondary deposits and identified as mixture of Aira Tn ash (ca.25ka) and Daisen Uh ash (ca.20 ± α ka) by means of thermomagnetic and also EDX analyses. From the results of fossil pollen analysis, the black organic soil is divided into three pollen zones in ascending order as follows; A zone (145-130 cm depth: Castanea & Castanopsis, Taxodiaceae &Cupressaceae, Betula, Cryptomeria), B zone (130-90 cm depth: Castanea & Castanopsis, Taxodiaceae & Cupressaceae, Cyclobalanopsis, Aesculus), C zone (90-35 cm depth: Taxodiaceae & Cupressaceae, Castanea & Castanopsis, Aesculus, Tsuga). the vegetation of the moor was inbestigated phytosociologically in 1980-1981 and 1988-1989. As the result of the studies, 5 communities were recognized. The following 3 communities with 2 sub-communities as a typical moor vegetation among them were discussed with the comparison of a secular change. 1) Eriocaulon miquelianum - Rhyncospora fauriei community 2) Hosta montana - Arundinella hirta community 　(2-1) Rhynchospora fauriei - A.hirta sub-community 　(2-2) Carex dispalata - A.hirta sub-community 3) Lythrum anceps - C.dispalata community (1) is an oligotrophic community favored by pudding water flowing from percolating underground water. (3) is an eutrophic community confined to the area near the stream.