Gradient analysis and classification of the woody vegetation for four sites in southern Illinois and adjacent Missouri

摘要: The woody vegetation and associated soil-site variables from a range of upland to swamp sites were measured using 480 0.04 ha plots Little Black Slough, Goose Pond Horseshoe Lake in Illinois, Mingo Wildlife Refuge, Missouri. Multiple regression, correlation, factor analysis used relate data structure composition. Coenoclines both the understory overstory constructed represent upland-swamp gradient region near northern terminus southern floodplain forest. Percent sand, depth flooding, silt content most strongly related coenocline. Depth clay Beta diversities coenoclines 5.8 6.9HC. Understory density basal area increased species richness heterogeneity decreased along gradient. Classification techniques identified three or four major types within each study area. 15 ordinated environmental characteristics summarized for each. Refuge had least flooding lowest soil content. all areas groups (mesic, swamp) eight groups. These include aQuercus velutina-Q. alba, Quercus rubra-Q. Liquidambar styraciflua-Ulmus americana, phellos-Q. palustris, lyrata-Acer rubrum, Acer rubrum-Nyssa aquatica, Nyssa aquatica-Taxodium distichum aTaxodium distichum-Nyssa aquatica type arranged swamp.