Identifying Reference Conditions for Riparian Areas of Ohio T · H · E OHIO srA1E October 2003 UNIVERSITY Special Circular 192 OARilr Ohio Agricultural Research and Development Center T · H · E OHIO SfA1E UNIVERSITY OARilr Steven A. Slack Director Ohio Agricultural Research and Development Center 1680 Madison Avenue Wooster, Ohio 44691-4096 330-263-3700 Identifying Reference Conditions for Riparian Areas of Ohio P. Charles Goebel School of Natural Resources Ohio Agricultural Research and Development Center David M. Hix School of Natural Resources The Ohio State University Marie E. Semko-Duncan School of Natural Resources Ohio Agricultural Research and Development Center T · H · E OHIO SfA1E October 2003 UNIVERSITY Special Circular 192 OARil[ Ohio Agricultural Research and Development Center Salaries and research support were provided by state and federal funds appropriated to the Ohio Agricultural Research and Development Center and Ohio State University Extension of The Ohio State University's College of Food, Agricultural, and Environmental Sciences. The use of trade, firm, or corporation names in this publication is for the information and con­ venience of the reader. Such use does not constitute an official endorsement or approval by the United States Department of Agriculture, the Agricultural Research Service, The Ohio State Uni­ versity, or the Ohio Agricultural Research and Development Center of any product or service to the exclusion of others that may be suitable. Abstract Using pre-European settlement vegetation broad forest types that once occurred across surveys and studies of the few remaining the state, they lack the site-specific informa­ old-growth remnant forests, we: tion on forest stand structure and vegetation­ environment relationships needed to • Determined the utility of using these adequately predict reference vegetative different sources of information to states. develop reference conditions for riparian forests of Ohio. The studies of the few remaining old-growth remnants do elucidate many of the finer­ • Identified gaps in our understanding of the ecology of Ohio's riparian forests scale vegetation-environment relationships, that need to be addressed to help providing considerable data on the overstory develop reference conditions for these composition and, in some cases, ground­ important landscape components. flora composition of these reference riparian systems. More information, however, is Based on an extensive review of the avail­ needed on the structure of these riparian able literature, we surmised that while forests in order to develop suites of ecologi­ pre-European settlement maps and surveys cally based reference conditions for Ohio's provide generalized information on the riparian forests. Introduction For a resource manager interested in tion (Wyant et al., 1995). This is particularly restoring plant communities in disturbed true for riparian areas, where variation in ecosystems, the identification of reference physiography, disturbance regimes, and soil vegetation conditions is an important step characteristics can result in a diverse array in the process of forest ecosystem restora­ of plant communities at a variety of spatial tion (Aronson et al., 1995; Pickett and Par­ scales (e.g., Gregory et al., 1991; Bendix and ker, 1994). Identifying reference conditions Hupp, 2000). (e.g., composition, structure, and function of woody and herbaceous species) for a specific A common source of information on histori­ ecosystem, however, is often a very conten­ cal plant communities that has often been tious issue. used to identify reference conditions for forest ecosystem restoration is the original Successional pathways and plant commu­ surveyor notes of witness trees, such as those nity composition and structure can be highly developed by the General Land Office (GLO) variable, making it difficult to use historical in the early 1800s. From these surveyors' plant communities as templates for restora notes, the pre-European settlement distribu 1 tion of forest ecosystem types has been Other less utilized sources of informa- developed, and relatively detailed infor­ tion on reference vegetation conditions mation on the historical composition and for forest ecosystem restoration are the structure of these forests has been deter­ remaining relatively undisturbed old­ mined. growth forest ecosystems. Although less than 1% of the pre-European settlement For example, in Ohio, Gordon (1966) forests remain in Ohio (Davis, 1996), there developed a pre-European settlement map are examples of minimally disturbed of forest types, and many resource mana­ old-growth(> 150 years old) and mature gers and conservation organizations use second-growth (120 to 150 years old) forest this classification to guide their selection of ecosystems in Ohio, many of which are reference vegetation conditions (Figure 1). located on public lands (e.g., Goebel and Hix, 1996). s CJ Ohio Pre-European Settlement Vegetation - Beech Forests CJ Mixed Oak Forests D Oak-Sugar Maple Forests - Elm-Ash Swamp Forests Mixed Mesophytic Forests CJ Prairie Grasslands CJ Oak Savannas CJ Freshwater Marshes and Fens - Sphagnum Peat Bogs CJ Bottomland Hardwood Forests 100 O 100 Kilometers D Mixed Mesophytic Forests (Hemlock-Beech-Chestnut-Oak) D White Pine-Red Maple Swamps ~~----~~~~ D Beaches Figure I. Presett/ement forest types of Ohio (based on Gordon, 1966). 2 Although they often represent a small and the few remaining old-growth forest area, these forests provide an opportunity ecosystems in each of Ohio's ecoregions to study vegetation-environment relation­ (McNab and Avers 1994; Figure 2) to: ships and develop predictive models of forest ecosystem development that can be • Determine the utility of using each used to develop templates for the restora­ of these sources to develop reference tion of forest composition and structure. conditions for riparian forests of As many of these old-growth forest eco­ small and large streams and rivers in systems also have small streams and rivers each of Ohio's ecoregions. flowing through them, they may provide • Identify gaps in our understand- useful information to develop reference ing of the ecology of Ohio's riparian conditions for riparian forests. forests that need to be addressed to The objective of our report is to review the help develop reference conditions for relevant literature related to the pre-Euro­ these important landscape compo­ pean settlement forest-type surveys nents. Riparian Areas and Reference Conditions Riparian areas are functional ecotones or (Ilhardt et al., 2000; O'Laughlin and Belt, transitional areas located between ter­ 1995). Unfortunately, we have a poor restrial and riverine ecosystems. Despite understanding of the patterns of variation their limited areal extent, riparian areas in riparian areas within and among water­ promote many ecosystem functions vital sheds, or the specific landscape features to the health and productivity of forested that control riparian vegetation develop­ watersheds. Not only do riparian areas ment. regulate the flow of water, sediments, and nutrients across system boundaries, Increasingly, riparian areas across Ohio they also contribute organic matter to the are experiencing pressure from a variety aquatic system, increase bank stability, of sources, including developers, farmers, reduce erosion, and provide key wildlife and recreationists. Detailed assessments of habitat (Gregory et al., 1991; llhardt et al., relatively undisturbed riparian areas are 2000). critical elements needed for a variety of ecological purposes, especially for provid­ Additionally, because of their functional ing a benchmark of reference ecological importance, riparian areas serve important conditions necessary for evaluating forest roles in mitigating many of the negative ecosystem restoration programs. impacts of land use on aquatic systems as well as protecting species diversity, pro­ Voluntary best management practices viding potential dispersal corridors for (BMPs) promoted by various state agen­ wildlife, and mitigating flood waters cies (e.g., the Ohio Department of Natu 3 •Drew r-----..1 Woods •Hueston Woods Ecoregions D Central Tiii Plains, Beech-Maple Section D Erie and Ontario Lake Plain Section - Interior Low Plateau, Bluegrass Section - South Central Great Lakes Section 100 0 100 Kilometers • Southern Unglaciated Allegheny Plateau Section ~~--~~~~ D Western Glaciated Allegheny Plateau Section Figure 2. Ecoregions of Ohio (McNab and Avers, 1994) and location of remaining old-growth and mature second-growth forests with information on riparian forests published in a refereed journal article. ral Resources, ODNR) may be available lineation of riparian areas is the need for and utilized in riparian areas (Blinn and an explicit quantification of reference, or Kilgore, 2001 ). However, the effective­ benchmark, riparian conditions (Gregory, ness of these practices to help restore or 1999). Although current management sys­ even maintain critical ecosystem linkages tems incorporate the best available science, is untested. These practices are certainly our understanding of specific riparian not site-specific in their application (e.g., areas and the extent of the functions asso­ the width of riparian management zones ciated with these land-water interfaces is is often fixed arbitrarily rather than being often incomplete (Blinn and Kilgore, 2001 ). based on a functional delineation of ripari­ an extent; deMaynadier and Hunter, 1995). Understanding the range