Ground-flora composition and structure of floodplain and upland landforms of an old-growth headwater forest in north-central Ohio

We compared the ground-flora (vascular plants <= 1 m tall) composition and structure of floodplain and upland landforms, and examined the influence of environmental factors on ground-flora composition and structure, in an old-growth headwater forest in the Western Glaciated Allegheny Plateau Ecoregion of Ohio. Soil pH, percent organic matter, sand content, and clay content were significantly higher on the floodplains than on the uplands, while the upland landforms were characterized by higher percentages of silt. Percent total nitrogen and concentrations of NO3--N, P, K, Ca, Mg, Mn and Zn were all significantly higher on floodplain landforms than on upland landforms. While species richness and diversity were similar between landforms, ground-flora composition and structure were different. Canonical correspondence analysis (CCA) associated graminoids and forbs with floodplains, while woody species were associated with uplands. Multi-response permutation procedure (MRPP) demonstrated that floodplains had higher cover of Impatiens capensis, Laportea canadensis, Leersia virginica, and Urtica dioica. Conversely, uplands were characterized by higher cover of Acer saccharum, Fagus grandifolia, Fraxinus americana, Parthenocissus quinquefolia, and Polygonatum pubescens. This study provides much-needed information on the vegetation-environment relationships of headwater riparian forest ecosystems that may be useful for riparian restoration in north-central Ohio.