Final Report for LNC95-089
The goals of this study were to determine whether intensive rotational grazing (IRG) can be used to allow farmers to harvest forage from riparian areas without compromising water quality and riparian habitats and to produce guidelines for environmentally sound management of riparian pastures.
Methods. A total of 21 farms were used as study sites during the two years of the study. All sites were located along spring-fed streams with potential for trout production. Trout streams are a source of recreational and tourism income for local communities, but are often heavily impacted by agricultural land use. Streamside vegetation was managed either as a grassy bufferstrip, a continuously grazed pasture, a rotationally grazed pasture or a woody bufferstrips (limited data collected). We collected data in the following areas: forage production and vegetation community, fish community and aquatic habitat, grassland birds, small mammals, amphibians.
Results. Rotational pastures produced much more forage than continuous pastures. The average amount of available forage on offer was 1,856 lb/a for ready-to-graze rotational pastures and 781 lb/a for continuous pastures. Forage quality did not differ significantly between pasture types. Grassy bufferstrips tended to have significantly different vegetation structure from rotational and continuous pastures, because they were not harvested in any way. Grassy bufferstrips developed tall, dense vegetation dominated by reed canarygrass and a few broadleaf species. Both continuous and rotational pastures had shorter, more diverse plant communities with native and non-native wildflowers and legumes.
Streambanks with grassy bufferstrips were the most stable. Grassy bufferstrips had the least bare ground (17%) on the bank slope, while rotational pastures averaged 24.2% and woody buffer strips and continuous pastures had the most bare soil at 29.9% for woody buffers and 33% for continuous pastures. Instream habitat was as good at rotationally grazed sites as it was at grassy bufferstrips and was better than at either continuous pastures or woody bufferstrips.
For all types of land management, fish community health was poor to fair. This is typical of this region, which has potential for quality trout fisheries, but has suffered from many years of poor land management. The condition of the watershed upstream from the site accounted for about 90% of the effects we saw at our study sites. However, when these upstream effects are factored out, grassy bufferstrips had the highest quality cold-water fisheries, rated fair versus poor ratings for rotational, continuous, and woody buffer sites. For aquatic insects, which are a food source for trout and an indicator of water quality, rotationally grazed sites were similar to grassy and woody bufferstrips and all three were better than continuously grazed sites.
Wildlife work was conducted on all sites except woody bufferstrips. We surveyed amphibians, birds, and small mammals and this work is ongoing. Preliminary results suggest that grassy bufferstrips and pastures provide habitat for specific species groups. Amphibians and declining species of grassland birds preferred pasture sites, while small mammals were found primarily in bufferstrips.
Impacts. Our results suggest that rotational grazing can provide a reasonable compromise between continuous grazing and fencing livestock out of riparian areas. We are working now to educate landowners as well as agency policy makers and field staff on management strategies for riparian areas. Our efforts include field days, public presentations, published papers and articles, and development of a riparian grazing guidelines handbook.
Riparian areas on livestock farms provide important habitat for wildlife and fish communities and a filter for pollutants. Unrestricted livestock access to streams has long been associated with degradation of these sensitive habitats and the traditional agency response has been to encourage fencing livestock out of riparian corridors. While effective, bufferstrips are seldom used because they take land out of production, restrict access to water for livestock, and require costly maintenance of fencing and vegetation. Intensive rotational grazing is a relatively new option for livestock farmers, which provides environmental as well as economic benefits. Our research suggests that it may be a reasonable compromise between continuous grazing and fencing livestock out of riparian areas altogether. This research compared three management options for riparian areas livestock farms, ungrazed buffer strips, rotational grazing, and continuous grazing, on 21 private farms along trout streams in Southwestern Wisconsin.
The study involved evaluation of aquatic and terrestrial wildlife community composition and habitat quality as well as forage production and quality. We observed both local land management and larger scale influences on our results. While adjacent land use appears to be a major determining factor in streambank stability and both instream and terrestrial habitat quality, wildlife and fish communities tended to respond more to broad watershed or landscape scale factors than to the local conditions created by the three treatments. Streambank stability and instream habitat were similar for bufferstrips and IRG pastures, but bufferstrips had healthier fish communities with more trout and fewer warm-water fish species. Continuous pastures had poor in-stream habitat quality and poor cold-water fisheries.
Rotationally grazed pastures produced twice as much forage than continuous pastures. Both rotationally and continuously grazed sites had more diverse plant communities than the grassy buffers. Bufferstrips were dominated by reed canarygrass, while pastures had a diverse mixture of grass species, legumes, and wildflowers. Bufferstrips, of course, were not harvested in any way and the vegetation became tall and rank over the course of the summer. The lack of harvesting in bufferstrips combined with the linear character of this habitat strongly influenced the response of the wildlife community.
Our results suggest that grazed riparian areas may be more suitable for amphibians and grassland birds than buffer strips, while small mammals were more numerous in bufferstrips than in pastures. Larger numbers of grassland bird species and individuals were observed in both rotational and continuous pastures than in grassy bufferstrips, although the density of birds was higher at bufferstrips. Species diversity and total abundance of grassland birds were greater adjacent to the stream than in upland counts at the same site. Both rotational and continuous pastures attracted more amphibians than bufferstrips. Conversely, many more small mammals, including one species of management concern, were found in bufferstrips than in riparian pastures.
Among the three treatments, bufferstrips had the healthiest aquatic communities, but did not provide the best habitat for all wildlife communities. Rotational grazing appears to provide a reasonable alternative that protects streambank stability and aquatic habitats and provides good habitat for grassland birds and amphibians. Intensive rotational grazing allows livestock farmers to maximize the productivity of riparian pastures without compromising habitat quality. On a watershed scale, a mixture of rotational pastures and bufferstrips along a stream would provide a diversity of habitats for terrestrial wildlife, protection for aquatic communities, and economically and environmentally sustainable choices for farmers.
The goals of this study were to determine whether IRG can be used as a best management practice (BMP) for riparian areas and to document IRG techniques that are likely to maintain or improve shoreline integrity and reduce water pollution while allowing profitable use of riparian areas by the farmer. Our specific objectives were:
1. Evaluate rotational grazing management for shoreland corridors and compare with continuously grazed and ungrazed riparian areas in terms of aquatic habitat, terrestrial habitat and forage production.
2. Develop, in partnership with graziers, guidelines for practical, environmentally sound grazing management of riparian areas.
3. Convey the developed guidelines to livestock farmers and extension, natural resources, and regulatory agency personnel through field days, publications, and other educational media.
We collected data in the following areas: forage production, streambank stability, fish and aquatic insect communities, instream habitat, and terrestrial wildlife surveys of birds, small mammals, amphibians, and insects. A total of 21 farms were used as study sites during the two years of the study. All sites were located within Wisconsin's Driftless Area--a region characterized by relatively pure, spring-fed streams with potential for trout production. Trout streams are a source of recreational and tourism income for local communities, but are often heavily impacted by agricultural land use. Each site included a trout stream with streamside vegetation managed either as a grassy bufferstrip with crop fields in adjacent uplands (six sites), a continuously grazed pasture (six sites), a rotationally grazed pasture (five sites) or a woody bufferstrips (four sites with limited data collected). Each riparian area had consistent management over the previous three years or more.
1. Assessment of in-stream biotic integrity and habitat. Fish and aquatic insect communities were documented and instream habitats were assessed at each farm. The length of each site along the stream was approximately 35 times the width of the stream. For each treatment study area, two sites were established: one within the treatment area and one upstream of that farm. The upstream site is used to help quantify the influence of overall watershed condition and upstream land use using a statistical method called analysis of covariance that calculates the proportion of variance accounted for by the adjacent land management vs. the overall condition of the watershed.
The study employed a modeling approach known as the Index of Biotic Integrity, which uses the composition of the fish community to evaluate the health of the aquatic ecosystem. It is based on the fact that these communities are exposed to the entire range of water quality conditions throughout the year, thus providing a broader assessment of the health of the habitat than analysis of individual water samples would. The index uses a series of measurements to determine a numerical score for each site, which is then compared to scores for sites with known high quality cold water fisheries. Samples of aquatic insects are collected from each site as well and similar indices were used to evaluate the composition of the invertebrate community. Aquatic insects provide an important food source for fish and can also provide an indication of overall water quality. The indices we are using are based on known tolerances of each species to aquatic pollutants. By evaluating the relative abundance of each of these species, we can draw conclusions about the quality of the water of a particular stream.
2. Assessment of streambank stability and aquatic habitat. Aquatic habitat features we evaluated include stream size and gradient, water temperature, depth, and clarity, discharge, substrate, instream cover for fish, and channel habitat units such as pools, riffles, and runs.
This assessment also included stream physical features such as stream channel morphology and flow, streambank soil alteration, undercut and vegetation cover, percentage of streambank slope, length of bank, percentage bare ground, and percentage of gravel cover. Detailed measurements of bank slope, length, percentage of bare ground, and percentage of gravel or rock cover were made four times: Fall 1996, Spring 1997, Summer 1997, and Fall 1997.
3. Riparian and streambank vegetation characterization. Vegetation was sampled at each of the study sites biweekly during the grazing season. Each week, we randomly located a series of three transects on each side of the stream (total of six). Each transect was placed perpendicular to the stream and extended from the bank out into upland areas adjacent to the riparian areas. For each transect, one set of measurements was done within 10 feet of the stream and two in the upland areas for a total of 18 samples per site per sampling date (three locations per transect x six transects). Sampling included: 1) percentage of cover of live and residual vegetation, 2) height and density of live vegetation, 3) depth of residual vegetation layer, 4) percentage of bare ground, 5) species composition of vegetation community.
4. Agronomic evaluation. Forage samples were collected bi-weekly throughout the grazing season at all pasture sites. Sampling was done along the same transects that were used for vegetation measurements. Samples were weighed fresh and dried for forage availability estimates and were analyzed for nutritional quality using near infrared spectrophotometry.
5. Terrestrial wildlife surveys. Amphibians, birds, small mammals, and ground beetles were surveyed at both streamside and upland locations at each site. Amphibians were surveyed using night calling surveys and ground searches. Calling surveys were conducted five times at each site during April-July each year, with each survey separated by two to three weeks. Ground searches were conducted once per month during this period. Birds were censused using 150ft radius point counts and area searches. Three point count surveys were conducted at each site between mid-May and the end of June each year. At the time of each bird census, a 20-30 minute area search of a 10a area within each site was conducted. Small mammals were sampled using 2-liter pitfall traps at the ends of eight 30 ft long drift fences at each site. Drift fences were located perpendicular to the stream at the streams edge and in upland locations. Baited live traps were also placed along the drift fences. At each site, traps were left open and checked twice per day for seven days. Ground beetles were sampled using pitfall traps in association with the drift fences.
6. Guidelines development. After two seasons of research, our group felt ready to tackle the goal of developing guidelines for sound riparian grazing management. Participants in this effort include farmers Dick and Kim Cates, Dan Patenaude, and Dick Ryan, fisheries biologist John Lyons, DNR administrator Jim Kurtz, and agronomists Laura Paine, Tim Rehbein, and Dan Undersander. We visited several of the cooperating farms and walked the streambanks, discussing challenges and issues involved in grazing management of streamside pastures. All comments were recorded and were organized into the enclosed booklet, which was then sent back to participants for initial review. At our recent annual meeting, over 60 people participated in a critique of the document and comments and questions were solicited. We hope to complete the review process in the next few months and publish the guidelines as an extension bulletin.
Vegetation status and forage availability. Grassy bufferstrips tended to have significantly different vegetation structure from rotational and continuous pastures because they were not harvested in any way. Height and density of vegetation were greatest in grassy buffer strips. Overall, grassy bufferstrips had less bare ground, similar total amounts of live vegetation cover, and more residual vegetation cover than rotational pastures, which were intermediate between the bufferstrips and continuous pastures. Grassy bufferstrips had fewer legumes present and more grass and forb (broadleaf) cover than either pasture type. However, both continuous and rotational pastures had more diverse plant communities with native and non-native wildflowers and legumes.
The average amount of available forage on offer was 1,856 lb/a for ready-to-graze rotational pastures and 781 lb/a for continuous pastures. Analysis of 1997 samples for nutritional quality is not yet complete. In 1996, nutritional quality was similar for the two treatments with crude protein levels averaging 17.8% and 17.2%, ADF levels of 36.7% and 39%, and NDF levels of 56.2% and 56.6% for continuous and rotational pastures, respectively.
Streambank stability. Height of stream banks was very similar among treatments, averaging just over five feet from water surface to the surface of surrounding level land. Bank angle or slope was greatest, averaging about a 42% slope, at grassy bufferstrip sites. Woody bufferstrips had an average slope of 34%, and continuous pastures and rotational pastures had an average slope of 28% and 25%, respectively. Grassy bufferstrips had the least bare ground (17%) on the bank slope averaged over the four measurement periods. Rotational pastures averaged 24.2% and woody buffer strips and continuous pastures had 29.9 and 33% bare ground, respectively. For all treatments except the grassy buffers, the highest percentage of bare ground was measured in the spring. For rotational pastures the percentage of bare ground on streambanks averaged less than 20% except for the spring measurement, which averaged 48.7%. This suggests that fall management of these areas must be improved to protect the banks from winter erosion. For continuous pastures and woody bufferstrips, spring percentages were highest, but the difference was less extreme. For grassy bufferstrips, the spring and fall 1997 measurements were similar at about 23%. Besides sod cover, the other stabilizing factor for streambanks is rock or gravel; however none of the sites had more than 6% rock cover on the streambanks.
Fish communities and aquatic habitat. Using analysis of covariance, with the upstream station data as the covariate, we determined that upstream or watershed effects were highly significant and accounted for 87-99% of the variation for fish and aquatic invertebrate variables. This finding indicates that aquatic communities at the study sites were responding to the overall watershed condition much more than they were to local land management within the study site. For all the sites, regardless of land management, fish community health was poor to fair. This is typical of this region, which has potential for quality trout fisheries, but has suffered from many years of poor land management. When upstream effects are factored out, there is evidence that grassy bufferstrips had more trout and the highest quality cold-water fisheries, although they were rated fair versus poor for rotational, continuous, and woody buffer sites.
Two indices using aquatic insect community composition helped us evaluate water quality. The EPT index and the Mean Tolerance index rate water quality based on ratios of species that have varying levels of tolerance to pollutants. For both indices, rotational sites scored as well as grassy and woody bufferstrips. All three were slightly better than continuously grazed sites. This suggests that livestock can be allowed access to streams through rotational management without having a significant impact on water quality. In addition, it suggests that aquatic insects, a major food source especially for young trout, are not negatively affected by rotational grazing management of stream areas.
For habitat variables, upstream conditions exerted a lesser effect on our results, accounting for 50-87% of the total variation observed. More of the results can be attributed to adjacent land management. For bank erosion rating and stream habitat index, rotational grazing scored nearly as well as grassy bufferstrips and better than either woody buffers and continuous grazing. The contrast between grassy and woody bufferstrips is an important finding because of the tendency of riparian areas to convert from grassy vegetation to shrubs and trees. Trees provide a number of benefits for streams in terms of providing shade to keep water temperatures cooler and providing inputs of organic matter (dead leaves) on which aquatic insects feed. Tree roots can also have a stabilizing effect on streambanks in some situations. Our data suggest that woody vegetation can also have negative effects on stream habitats. The decline that we’ve documented in habitat quality as woody vegetation becomes established suggests that efforts should be made to maintain riparian vegetation in grass in at least portions of watersheds. One of our participating farmers has maintained grassy vegetation along the banks of his stream for 20 years using mowing and spot applications of herbicides, but few landowners have the time or inclination to do this. An alternative approach to managing riparian vegetation would be to use grazing. Fisheries manager Dave Vetrano uses livestock grazing to control brush in fishing easement areas in his region. We hope to do further research investigating the use of grazing for this purpose.
Wildlife surveys. Wildlife work was conducted on all sites except woody bufferstrips.
Amphibians. Data analysis on amphibians has not been completed, however results from both years suggests that continuous and rotational pastures each supported a greater abundance and diversity of amphibians than did bufferstrips. Primary species found at pasture sites included leopard frogs, American toads, and the declining pickerel frog. Our results suggest that, while grazed riparian areas may be more suitable for amphibians than bufferstrips, differences between continuously and rotationally grazed sites in amphibian abundance or species composition are not yet apparent.
Grassland Birds. The presence of water at the study sites was probably the single biggest factor determining the density of birds at study sites. Species diversity and total abundance were greater adjacent to the stream than in upland counts at the same site for all treatments. Densities were highest in the narrow, linear habitat created by the bufferstrips. Several of the more common grassland bird species such as brown-headed cowbirds, killdeer, song sparrows, red-winged blackbirds, and American goldfinches, occurred in both pasture types and in grassy bufferstrips. A number of grassland bird species are considered to be of management concern in Wisconsin and the North Central Region because of declining populations. Only one of these species, the savannah sparrow, was observed in a single grassy bufferstrip site. Grassland bird species occurring in both rotational and continuous pastures included declining species: eastern meadowlarks, savannah sparrows, grasshopper sparrows, and bobolinks. More of these species occurred in continuous pastures; however this trend seems to be related more to pasture size than to management. In a previous study of upland pastures, we found that rotationally grazed pastures attracted more declining grassland species and individuals than continuously grazed pastures. Landscape scale features may have been a factor in the presence or absence of birds at some sites. Sites that were surrounded by an open landscape tended to have more grassland bird species than those that were in more wooded areas. Further research is being done to clarify the relationship between pasture size, surrounding landscape features, and grassland bird activity.
Small Mammals. Bufferstrips supported more small mammal species and more individuals than either rotational or continuous pastures. Very few small mammals were trapped in any of the study sites in 1996 and trapping efforts were greatly increased in 1997. Preliminary observations for the two years suggest that bufferstrips provide suitable habitat for a much larger and more diverse small mammal community. A total of 10 species were trapped in buffers (311 individuals), four species in rotational pastures (63 individuals), and four species in continuous pastures (54 individuals) during the study. Two species: the western harvest mouse and the prairie vole, are considered of management concern in Wisconsin. Of these, only the western harvest mouse was captured in our study and only in grassy bufferstrips. Factors most likely responsible for these differences include greater cover and depth of litter layer and greater live vegetation height and density. The only species that appeared to prefer pasture habitat was the 13-lined ground squirrel, a burrowing species. Most small mammal species undergo wide population fluctuations from year to year. The differences that we are seeing are very likely a response to our treatments, but additional data collection will document the interactions between habitat and annual population fluctuations. We plan to continue the wildlife portion of this research for another year to verify these results (the wildlife work has been supported by funding sources other than the SARE program).
Ground Beetles. Preservation and identification of ground beetles collected during the study has just been completed and these data have not been analyzed yet.
The goal of this study was to investigate the relationships between riparian land management and natural resources protection on livestock farms. Our results suggest that management intensive grazing is an appropriate alternative BMP to grassy bufferstrips in terms of water quality and aquatic habitat protection. In terms of terrestrial habitat management, it appears that each BMP provides habitat for different species and that both should be included in watershed management plans.
Like other states, Wisconsin agencies are currently considering regulations for management of shoreland areas within the state. Agency regulatory personnel view intensive rotational grazing as a potential BMP for these areas, but little data is available to back up anecdotal information or to provide specific grazing guidelines. Based on our research, we are developing guidelines for environmentally sound rotational grazing of riparian areas on farms. This study provides the data needed to craft regulations, when necessary, that are reasonable and cost-effective. The other major contribution that this research has made lies in strengthening connections between the natural resources community and the farming community. There is a certain level of distrust between the two groups that has built up over many years and this barrier must be broken to allow communication between the two groups, whose goals are not as different one might think. This project has moved us in that direction.
Economic analysis was beyond the scope of this project. All farms involved, however, were financially solvent, and the grass farmers we are working with have been able to make modifications to improve riparian protection and water quality without undue economic hardships. Primary costs for appropriate management of streamside pastures are in management time, installation of stream crossings, and some additional fencing. Costs vary with the character of the stream, the operation, and the level of management the farmer is comfortable with.
A total of 21 farms were involved in the study to a greater or lesser extent. Some farmers simply gave us permission to collect data on their property, whereas others are closely involved in the study, participating in data collection and monitoring results. Six of the farmers are practicing rotational grazing and have adopted environmentally sound practices to protect their stream areas. Four farmers will continue to work closely with us on the second phase of the project. Many other graziers in the Upper Midwest are aware of our research and are monitoring our progress. Our planned expansion of the study will broaden the involvement of graziers in other watersheds throughout the state. More extensive outreach efforts will be ongoing as research continues. We will revise our riparian grazing guidelines and begin distribution of them in the coming year and are planning to conduct joint field days with the Land Stewardship Project of Minnesota's Monitoring Team.
Involvement of Other Audiences. Our field day, hosted by Dick and Kim Cates, cooperating beef farmers, targeted local and statewide agency personnel. Approximately 50 people attended, including Wisconsin Department of Natural Resources and Department of Agriculture officials and area managers, Natural Resources Conservation Service personnel, and representatives of non-profit organizations such as the Nature Conservancy, the Audubon Society, Grassworks, Inc., and the Wisconsin Rural Development Center.
Participants in the study include members of our steering committee: the Agricultural Ecosystems Research Group. This committee comprises our primary vehicle for disseminating information and includes members of the general public, representatives of grazing networks and private non-profit environmental groups, farmers, agency personnel from the Wisconsin Department of Natural Resources, the Wisconsin Department of Agriculture, Trade, and Consumer Protection, the USDA Natural Resources Conservation Service and Farm Service Agency, the University of Wisconsin Departments of Agronomy, Biological Systems and Mechanical Engineering, Wildlife Ecology, and the Center for Integrated Agricultural Systems.
Educational & Outreach Activities
1. Field Days. Dick and Kim Cates, cooperating beef farmers, hosted a project field day on 12 September 1997. The morning session was a get-together for participating landowners, then in the afternoon, approximately 50 participants attended the more formal part of the field day, which targeted local and statewide agency personnel and natural resources organizations. Presentations were given by fisheries biologist John Lyons, agronomist Dan Undersander, wildlife ecology graduate students Roz Renfrew and Erik Chapman, water chemist Steve Greb, and farmers Dan Patenaude and Dick and Kim Cates.
In addition, we have presented information at the 1997 Wisconsin Farm Progress Days in Manitowoc County and a Prairie Pastures field day in Iowa as well as other agricultural field days and pasture walks. We provided information on the study to graziers at the Wisconsin Grazing Conference in February, 1998.
2. We've had three graduate students working on the project: two in Wildlife Ecology under the direction of Dr. Chris Ribic, and one in Zoology, under the direction of Dr. Stanley Dodson. All are supported primarily by funds from other sources contributed to match SARE funding.
3. A recent article in the UW College of Agricultural and Life Sciences Quarterly Newsletter (attached) has attracted much attention to the project. We’ve had inquiries from many agency people and farmers from Wisconsin, Minnesota and Iowa, as well as from New York, Pennsylvania, Ontario, and other states and provinces.
4. Development of educational materials such as extension and technical bulletins for the farming community, agricultural agents and natural resources personnel. We have begun to work on development of these materials. A draft of a riparian grazing guidelines document is attached.
5. Presentation of collected data to the scientific community in the form of journal articles and presentations at appropriate conferences and seminars. Preliminary wildlife data were presented at The Wildlife Society Annual Conference in Cincinnati, Ohio (1-5 October 1996) and the annual meeting of the American Ornithologists' Union in Minneapolis, MN (13-16 August 1997). Preliminary fisheries data were be presented at the Annual Meeting of the Wisconsin Chapter of the American Fisheries Society, 7-9 January 1997, Oshkosh, WI and at the Annual Meeting of the American Society of Ichthyologists and Herpetologists in Seattle, WA (26 June-2 July 1997). The study was summarized in a poster presentation at the 1997 Soil and Water Conservation Society Annual Meeting in Toronto (23-26 July 1997). Individual papers on wildlife results and on fisheries results were given at the 1997 Midwest Fish and Wildlife Conference in Milwaukee, WI (7-10 December 1997). The entire study was summarized at annual meetings of the Agricultural Ecosystems Research Project in January, 1997 and February, 1998. Additional presentations are planned, including a talk at the American Forage and Grassland Council Annual Conference (8-11 March 1998). Several manuscripts will be prepared in the coming months for submission to appropriate scientific journals.
Areas needing additional study
Based on what we've learned, development and testing of specific techniques to protect streambanks from cattle damage during vulnerable periods will be an important next step in enhancing the potential of rotational grazing as an environmentally sound practice for riparian areas. In our planned work, we hope to test and refine these techniques not only on trout streams, but on cool and warm water systems within the North Central region. In addition, we hope to collect information on environmental impacts of the large herd confinement systems that also are becoming more common in the region.