UCBN and GRYN sagebrush steppe vegetation monitoring; double observer study 2015: John Day Fossil Beds National Monument-Clarno Unit and City of Rocks National Reserve
Esposito DM, Shanahan E, Rodhouse T. 2016. UCBN and GRYN sagebrush steppe vegetation monitoring; double observer study 2015: John Day Fossil Beds National Monument-Clarno Unit and City of Rocks National Reserve. Natural Resource Data Series. NPS/UCBN/NRDS—2016/1052. National Park Service. Fort Collins, Colorado
In June and July of 2015 the Upper Columbia Basin and Greater Yellowstone Inventory and Monitoring Networks conducted a double observer study of ocular cover class estimation in quadrats while engaged in annual sagebrush steppe (upland) vegetation monitoring. Both groups followed the same standard protocol (Yeo et al. 2009) for annual monitoring. While the goal of the double observer study was the same for both groups, slightly different field methodologies were adopted by each to best integrate with their standard work flow and field safety processes. The goal of this study was to determine the extent to which variation in visual estimation of plant cover between observers is influencing sagebrush vegetation monitoring data, and if there is a need to further develop data analysis techniques to account for this source of error. Our objectives were to: (A) determine how much visual estimation of cover and selection of cover classes varied between two independent observers within the same plot; (B) determine how significant the variation was; and (C) determine how much variability occurred in species detection (net species richness) between two independent observers within the same plot. In general, variability between observers in species detection was minimal, with most discrepancies occurring among species recorded at the lowest cover class. Discrepancies in cover class estimation between observers were generally less than 2 classes, with the largest amount of variability observed in the estimations of cover classes for bare ground, and for some non-native annual grasses. Potential issues with species identification were revealed in a small percentage of records where two different, but similar looking species were recorded by alternate observers at the same cover class in a double-observation plot. These findings suggest that a model-based approach to account for observation error may be helpful, but not urgent, given the relatively small amount of discrepancies found (interpreted as an indication of observer error) and the very large sample sizes that are routinely achieved in annual monitoring.
- Type
- Published Report
- Authors
- Esposito, Daniel; Shanahan, Erin; Rodhouse, Tom
- Date of Issue
- 2016-08
- Publisher
- National Park Service
- Units
- BICA , CIRO , GRYN , JODA , NRSS , UCBN
- Keywords
- Adaptive management, bunchgrasses, Invasive Plant Inventory, Invasive Plants, Monitoring, Non-Native Plants, prioritizing, PWR-toolkit, Sagebrush, Sagebrush steppe, Sagebrush Steppe Monitoring, Vegetation Inventory