Evaluation of Bureau of Land Management Protocols for Monitoring Stream Condition

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Virginia Tech


The goal of the Aquatic Indicators of Land Condition (AILC) project is to develop analytical tools that integrate land condition information with stream condition for improved watershed management within the United States Bureau of Land Management (BLM). Based on the goal of the AILC, two objectives for this study were: to determine the effect of four GIS-derived distance measurements on potential relationships between common BLM landscape stressors (mining and grazing) and changes in benthic macroinvertebrate community structure; and to assess the effectiveness of individual questions on a commonly-used Bureau-wide qualitative stream assessment protocol, the proper functioning condition (PFC) assessment.

The four GIS distance measurements assessed for biotic relevance included: straight-line distance, slope distance, flow length, and travel time. No significant relationships were found between the measured distance to stressor and macroinvertebrate community structure. However, the hydrological relevance of flow length and travel time are logically superior to straight-line and slope distance and should be researched further.

Several individual questions in the PFC assessment had statistically significant relationships with the final reach ratings and with field-measured characteristics. Two of the checklist questions were significantly related to the number of cow droppings. This may indicate a useful and efficient measure of stream degradation due to grazing. The handling and use of the PFC assessment within the BLM needs further documentation and examination for scientific viability, and the addition of quantitative measurements to the PFC in determining restoration potential would be desirable.



qualitative assessments, benthic macroinvertebrates, Geographic Information Systems, Riparian areas, Livestock Grazing