Impacts of Rotational Grazing and Riparian Buffers on Physicochemical and Biological Characteristicsof Southeastern Minnesota, USA, Streams

Abstract

We assessed the relationship between riparian management and stream quality along five southeastern Minnesota streams in 1995 and 1996. Specifically, we examined the effect of rotationally and continuously grazed pastures and different types of riparian buffer strips on water chemistry, physical habitat, benthic macroinvertebrates, and fish as indicators of stream quality. We collected data at 17 sites under different combinations of grazing and riparian management, using a longitudinal design on three streams and a paired watershed design on two others. Continuous and rotational grazing were compared along one longitudinal study stream and at the paired watershed. Riparian buffer management, fenced trees (wood buffer), fenced grass, and unfenced rotationally grazed areas were the focus along the two remaining longitudinal streams. Principal components analysis (PCA) of water chemistry, physical habitat, and biotic data indicated a local management effect. The ordinations separated continuous grazing from sites with rotational grazing and sites with wood buffers from those with grass buffers or rotationally grazed areas. Fecal coliform and turbidity were consistently higher at continuously grazed than rotationally grazed sites. Percent fines in the streambed were significantly higher at sites with wood buffers than grass and rotationally grazed areas, and canopy cover was similar at sites with wood and grass buffers. Benthic macroinvertebrate metrics were significant but were not consistent across grazing and riparian buffer management types. Fish density and abundance were related to riparian buffer type, rather than grazing practices. Our study has potentially important implications for stream restoration programs in the midwestern United States. Our comparisons suggest further consideration and study of a combination of grass and wood riparian buffer strips as midwestern stream management options, rather than universally installing wood buffers in every instance. RID="" ID="" The Unit is jointly sponsored by the US Geological Survey, Biological Resources Division; the Minnesota Department of Natural Resources; the University of Minnesota; and the Wildlife Management Institute.

Land Use, Stream Habitat and Benthic Invertebrate Assemblages in a Highly Altered Iowa Watershed

“…Additionally, nitrate concentration at each of our study sites (range 5 5.6-29.0 mg/L) was higher than 3.2 mg/L, a threshold value that, based on a USEPA Wadeable Streams Assessment, is indicative of poor conditions in Midwestern streams (Van Sickle and Paulsen, 2008). Turbidity in our study was similar to levels recorded in another study of a Midwestern stream within a row-crop dominated watershed, but on average much higher than turbidity recorded in cattle grazed landscapes of southern Minnesota (Sovell et al, 2000;FigueroaNieves et al, 2006). Diurnal oxygen concentrations in both urban and agricultural areas of our study were occasionally below minimum levels considered necessary to support stream biota (5 mg/L; IDNR, 2002).…”

“…Several previous studies investigated relationships among land cover, stream habitat and invertebrate assemblages in the Midwest (e.g., Richards and Host, 1994;Lammert and Allan, 1999;Sovell et al, 2000;Weigel et al, 2000;Nerbonne and Vondracek, 2001;Weigel, 2003;Nassauer et al, 2004;Hrodey et al, 2009), and a few such studies compared agricultural and urban land use effects on invertebrate habitat and assemblages (Stewart et al, 2001;Stepenuck et al, 2002;Wang and Kanehl, 2003). Results from aforementioned studies and our study suggest that urbanization has greater adverse effects than agriculture on invertebrate assemblages in the Midwest.…”

Benthic Macroinvertebrate Responses to Increasing Levels of Cattle Grazing in Blue Ridge Mountain Streams, Virginia, USA

“…In studying agriculture intensity along a river continuum in New Zealand, Harding et al (1999) suggested that the intensity of agriculture may be more useful in assessing river health than the percent of agricultural land use in a watershed. Sovell, Vondracek, Frost, and Mumford (2000) compared five macroinvertebrate metrics among streams subjected to rotational and continuous cattle grazing in Minnesota, USA and found inconsistent macroinvertebrate metric responses among sampling periods and within streams. In Alberta, Canada, Scrimgeour and Kendall (2003) used a 2-year, cattle-enclosure study to examine the benthic macroinvertebrate response to four livestock grazing treatment levels.…”

Streambank erosion in two watersheds of the Central Claypan Region of Missouri, United States

“…There are, however, many practices available for mitigating streambank erosion year round, including traditional engineering approaches (Bentrup and Hoag 1998;Schultz et al 2004), bioengineered systems (Bentrup and Hoag 1998), and establishment of riparian forest buffers and grass buffer strips (Gregory et al 1991;Schulz et al 2004). There is also extensive evidence that exclusion of cattle from riparian zones, either as part of a rotational grazing system or by fencing them from streambanks, reduces erosion (Platts 1981;Kauffman and Krueger 1984;Bentrup and Hoag 1998;Belsky et al 1999;Sovell et al 2000;Clary and Kinney 2002;Walker et al 2009). Given the seasonal nature of streambank processes observed in this study, exclusion of cattle from streambanks during the winter months may be especially beneficial.…”