contributed by Lindsey Goss
Description and Uses
Streambank alteration is a measure of livestock trailing, trampling, and shearing that occurs along the streambanks. This method is an annual or short-term indicator of grazing intensity and can be used as a trigger for moving livestock at a predetermined standard level or as an end of season indicator of current year livestock use.
There are several methods for evaluating streambank alteration including modified line intercepts with a sampling frame and step point intercepts measured at specified intervals along fixed-length transects, continuous line intercepts transects, and ocular estimations. The overall goal of these methods is to estimate how much of the streambank has been altered by livestock.
Advantages and Limitations
Streambank alteration is very quick and easy method for monitoring annual livestock disturbance to riparian areas. It serves as short-term estimation of the effect of grazing impacts on long-term stream conditions (eg. bank stability and channel morphology) which change slowly over time. Streambank alteration is not a standalone method for assessing grazing intensity and is generally evaluated in conjunction with additional indicators of livestock use such as residual stubble_height and woody browse utilization. This is not appropriate method to implement on streambanks that are resistant to hoof penetration (e.g. cohesive soil containing clay on dry or entrenched channels) or impervious to disturbance (e.g. bedrock or boulder armored stream channels).
- Multiple Indicator Monitoring (MIM) of Stream Channels and Streamside Vegetation (Burton et al. 2011) http://www.blm.gov/nstc/library/pdf/MIM.pdf
An example of the MIM sample design used to monitoring streambank alteration. The monitoring frame is placed every 2.75 meters along fixed-length transects on each streambank.
Example of the MIM monitoring frame with five line intercepts projected on the plot. There are four hoofprints on this plot. Lines 2 and 4 each intersect one hoofprint. Line 3 intersects two hoofprints. Three lines intersect hoofprints, so the number of alterations on this plot is recorded as a 3. See the above technical reference for detailed instructions on how to implement this method.
Technical and Application References
- Burton, T. A., S. J. Smith, and E. R. Cowley. 2011. Riparian area management: Multiple indicator monitoring (MIM) of stream channels and streamside vegetation. Denver, Bureau of Land Management. Technical Reference BLM/OC/ST-10/003+ 1737. 155 p. http://www.blm.gov/nstc/library/pdf/MIM.pdf
- Heitke, J. D., R. C. Henderson, B. B. Roper, and E. K. Archer. 2008. Evaluating livestock grazing use with streambank alteration protocols; challenges and solutions. Rangeland Management and Ecology 61:647-655.
- Region 1 Bank Alteration Task Group. 2006. Standardized protocol for measuring bank alteration on grazing allotments for Region One National Forests, Final Report. http://www.fs.fed.us/rm/boise/research/techtrans/projects/pacfish/2009/r1-streambank-protocol.pdf
- Woody Browse Utilization
- Stubble Height