Temporal Changes in Spring Ground-flora Communities Across Riparian Areas in a North-Central Ohio Old-Growth Forest

—Spring ground-flora composition and structure were sampled along riparian areas in Johnson Woods State Nature Preserve, an old-growth oak-maple-beech forest in northcentral Ohio. Seven transects that bisected the stream valley were surveyed during early and late spring. Ground-flora communities differed between early and late spring and on landforms during each survey. Early spring floodplains were dominated by Floerkea proserpinacoides and Ranunculus septentrionalis, while late spring floodplains were dominated by Geum vernum and Leersia virginica. Early spring uplands were dominated by Anemone quinquefolia and Cardamine concatenate, while late spring uplands were dominated by Parthenocissus quinquefolia and Podophyllum peltatum. Principal components analysis showed a complex environmental gradient from stream channel edge into the surrounding uplands strongly related to soil characteristics and landform. The variability observed between early and late spring surveys suggests the need for multiple surveys in both spring and summer in order to gain a complete record of groundflora communities. Riparian areas are complex ecotones between aquatic and terrestrial ecosystems creating unique gradients that influence the structure and composition of plant communities. Riparian areas fulfill several important functions including regulating nutrient and energy flow between the terrestrial and aquatic systems (Gregory et al. 1991), providing unique habitat with high species richness and diversity (Goebel et al. 2003c), offering corridors for wildlife movement (Hodges and Krementz 1996), and creating aesthetic appeal (Kline et al. 2000). In many locations these unique systems have been destroyed and their functions disrupted. As a result, ecological, as well as economical, problems have arisen including poor water quality, stream bank erosion, and a decline in populations of flora and fauna. Where these problems are especially severe, restoration of the riparian area is often selected as a solution. Existing methods that describe riparian restoration are vague and generic (Lee et al. 2000) leaving those who wish to restore riparian areas at a loss for specific guidance. In order to generate better information for restorationists, a reference ecosystem on which to base objectives and goals of a restoration is needed (Pickett and Parker 1994; Aronson et al. 1995). Reference ecosystems provide information on structure, composition, and underlying dynamics that drive sustainable ecosystem functions. In Ohio, many of the riparian areas have undergone some form of disturbance from agriculture, logging, or urbanization. Therefore, locating undisturbed ecosystems to study for reference conditions is difficult. While scarce, isolated tracts of old-growth forest exist that reflect minimal anthropogenic disturbance. Many of these old-growth forests have small streams or rivers running through them with intact native riparian areas that may be studied as reference ecosystems. The limited number of riparian reference areas that have been identified and studied in Ohio focus mainly on overstory composition, while largely ignoring ground-flora composition and structure (Goebel et al. 2003b, McCarthy 2003). Studies that address ground-flora tend to focus on one survey, usually in mid-summer when spring ephemerals have disappeared. As flora is variable throughout a growing season, it is important to have a complete floristic record of a reference ecosystem (McCarthy 2003). The objectives of this study were (1) to compare and contrast composition and structure of early and late spring ground-flora in riparian areas of an old-growth forest and (2) characterize a spring groundflora reference condition for riparian restoration in north central Ohio. Graduate Research Associate (KLH), Research Associate (MSD), and Assistant Professor (PCG), School of Natural Resources, Ohio Agricultural Research and Development Center (OARDC), The Ohio State University, 1680 Madison Avenue, Wooster, OH 44691. KLH is corresponding author: phone (330) 263-3787 or email at holmes.203@osu.edu.