Determining which vegetation sampling strategies to employ is dependent on project objectives, and understanding how different indicators and attributes compare allows decision-makers to select the most appropriate and cost-effective choice. We looked at four indicators (basal cover, aerial cover, plant rank by dry weight (DWR), plant frequency) and one attribute (species composition) to determine whether the ranked order of perennial graminoid species varied between these five sampling strategies and which strategies identified the most comprehensive graminoid list. In 2013, macroplots were measured in high elevation mountain meadows (n=9, Apache-Sitgreaves National Forests, eastern Arizona) and in desert grasslands (n=4) and Madrean evergreen woodlands (n=4) in the Coronado National Forest (southeastern Arizona). A Kendall's tau-b correlation was performed to determine the relationship between the five strategies across the three ecosystems. All tests had a strong, positive correlation between strategies, suggesting that within each ecosystem the ranked order of species does not differ between indicators and the attribute. Each strategy identified a different number of species. In meadows, frequency identified the most graminoid species, suggesting frequency is sufficient to establish a comprehensive graminoid list. In desert grasslands, frequency detected the most graminoid species, but species composition, aerial cover, and DWR found similar numbers of species. In woodlands, species composition/aerial cover identified the most graminoid species, suggesting these strategies can detect rare species. On most macroplots, basal cover was unable to detect rare/less-common graminoid species compared with other strategies. Preliminary findings suggest frequency identified the most species in ecosystems with a relatively simple (one layer) vegetation structure (mountain meadows/desert grasslands). Species composition/aerial cover detected the most species in rangelands with more complex structures (oak woodlands). Vegetation structure may dictate which sampling strategies are most appropriate. Frequency combined with another attribute or indicator likely provides the most comprehensive understanding of the perennial graminoid community.
Oral presentation and poster titles, abstracts, and authors from the Society for Range Management (SRM) Annual Meetings and Tradeshows, from 2013 forward.