Research Summaries

Share
Hook, P. B.
2003. Sediment retention and rangeland riparian buffers. Journal of Environmental Quality 32:1130-1137.

Controlling non-point source sediment pollution is a common goal of riparian management, but there is little quantitative information about factors affecting performance of rangeland riparian buffers. This study evaluated the influence of vegetation characteristics in a Montana foothills meadow. Three vegetation types (sedge wetland, rush transition, bunchgrass upland) were compared using twenty-six 6×2 meter plots, spanning 2 – 20% slopes. Plots were clipped moderately (10-15 cm stubble height) or severely (2-5 cm stubble). Sediment (silt + fine sand) was added to simulated overland runoff 6, 2, or 1 meter above the bottom of each plot. Sediment retention was affected strongly by buffer width and moderately by vegetation type and slope, but was not affected by stubble height. Mean sediment retention ranged from 64 to 99% for different combinations of buffer width, and vegetation type or slope. Results suggest that rangeland buffers should be at least 6 meters wide, with dense vegetation, to be effective and reliable. Narrower widths, steep slopes, and sparse vegetation increase risk of sediment delivery to streams. Vegetation characteristics such as biomass, cover, or density are more appropriate than stubble height for judging capacity of remove sediment from overland runoff, though stubble height may indirectly indicate livestock impacts that can affect buffer performance.

 


Paine, L. K. and Christine A. Ribic.
2002. Comparison of riparian plant communities under four land management systems in southwestern Wisconsin. Agriculture, Ecosystems, and Environment 92:93-105.

Riparian plant community composition is influenced by moisture, erosion, original native plant communities, and current and past land use. This study compared riparian plant communities under four types of management: woody buffer strip, grassy buffer strip, rotational grazing, and continuous grazing. Study sites were located along spring-fed streams in the unglaciated region of southwestern Wisconsin. At each site, plant community surveys were conducted using a point transect method. Among the treatments, woody buffer strips, rotationally grazed, and continuously grazed riparian areas had greater plant species richness that grassy buffer strips, and woody buffer strips had the greatest native plant species richness. Reed canarygrass (Phalaris arundinacea) was prevalent in grassy buffer strips (44% of all observations), common in woody buffer strips (15%), and rare in sites that were rotationally grazed (3 and 5%, respectively). Pasture sites had greater proportions of native grass and grass relatives and moderate levels of overall native species richness. Considered a water quality best management practice, well-managed rotational grazing may be a reasonable alternative to buffer strips which can be contribute to protection and enhancement of native vegetation biodiversity.

 


Katz, G. L, and P. B. Shafroth.
2003. Biology, ecology and management of Elaeagnus angustifolia L. (Russian olive) in Western North America. Wetlands 23:763-777.

Elaeagnus angustifolia (Russian olive) is an alien tree that is increasingly common in riparian habitats of western North America. This paper reviews the pertinent scientific literature in order to determine the status of E. angustifolia as a riparian invader and to suggest ecological reasons for its success. Ecological characteristics likely enabling its invasiveness include adaptation to the physical environmental conditions that characterize semi-arid riparian habitats, lack of intense pressure from herbivores, and tolerance of the competitive effects of established vegetation. We believe that the success of this species is at least partly due to its ability to take advantage of the reduced levels of physical disturbance that characterize riparian habitats downstream from dams. Control of E. angustifolia is likely to be most promising where natural river flow regimes remain relatively intact.

 


Giulliano, W. M. and J. D. Homyack.
2004. Short-term grazing exclusion effects on riparian small mammal communities. Journal of Range Management 57:346-350.

Grazing of livestock in streams and associated riparian habitats (hereafter referred to as riparian zones) may affect small mammal communities by influencing vegetation, water quality, and other site characteristics. To better understand these effects, we compared vegetation structure, and abundance and richness of small mammals in grazed riparian zones and similar areas where livestock had recently (1-2 years) been excluded in southwestern Pennsylvania, 1998 and 1999. Mammalian species richness and abundance (all species combined, meadow voles and meadow jumping mice) were greater on sites where livestock had been excluded than grazed areas. These findings are likely the result of greater litter cover and increased vertical vegetation obstruction observed on these sites. Because small mammal communities respond quickly to relaxation of grazing in riparian communities, programs exist to partially pay for fencing, and landowners may potentially benefit from fencing these areas through improved water quality, erosion control, and livestock health. Fencing may be an effective wildlife and grazing management tool.

 


Gutierrez, L. R., J. E. Herrick, and G. B. Donart.
2004. Gully seeder for reseeding rangeland and riparian areas. Journal of Range Management 57:399-401.

Traditional methods of reseeding degraded arid and semi-arid rangeland are expensive and frequently unsuccessful due to high rates of seed predation and seedling mortality. A runoff-based method is described that protects seeds from predation and degradation until soil moisture is available, then deposits them in favorable microsites for germination and establishment. Seeds are placed in three, 2 cm-diameter x 8 cm PVC tubes. The small tubes are capped with crepe paper and glued inside of a 7.5 cm-diameter x 15 cm long tube that is capped with hardware cloth. The tubes are placed in small rills, gullies, arroyos or riparian areas and the seeds are released sequentially from the 3 tubes as flow depth increases. Seeds are deposited beneath piles of litter where soil moisture and temperature are more favorable for seedling establishment.