Comparison of 2 Vegetation HeightMethods for Assessing Greater Sage-GrouseSeasonal Habitat

摘要

The 2015 Sage-Grouse Habitat Assessment Framework (HAF) was developed to evaluatehabitat quality for sage-grouse (Centrocercus spp.), with the greater sage-grouse (C. urophasianus) as theprimary focus of HAF evaluations and basis of the indicators in the HAF. Site-scale assessments of sagegrousehabitat can be completed using either data collection methods described in the HAF or core methodsadopted by the U.S. Bureau of Land Management’s Assessment, Inventory, and Monitoring (AIM)program. However, there is a discrepancy in how vegetation height is measured between HAF and AIMmethods, which has led to confusion as to which protocol should be used and if the AIM height method iscompatible with the HAF for habitat assessments. Our objective was to use simulations and data frommultiple study areas to determine how often differences between the 2 methods would result in a differentdetermination of quality for the vegetation-height habitat indicator. We confirmed that the AIM methodgenerally yields lower estimates of height than the HAF method because it estimates mean vegetation heightwhereas the HAF method estimates mean maximum height (d 0.031). However, differences betweenmethods at the plot level most often were not substantial enough to lead to a different conclusion about theHAF vegetation-height indicator for habitat quality. There is value in implementing the AIM methodbecause it is widely used for other monitoring purposes, and slight modifications to the AIM technique (i.e.,increasing measurement frequency, adding measurements for both grasses and forbs) could improveusefulness for sage-grouse habitat assessments.