Abstract: The Intermountain West Joint Venture (IWJV) has embraced a strategic conservation philosophy for avian habitats in the Intermountain West guided by the principles of strategic resource allocation and implemented through a Strategic Habitat Conservation framework (SHC). However, science resources (i.e., funding, personnel capacity, information) are often lacking for most entities to fully implement all key elements identified in the adaptive management framework (SHC). The IWJV is no exception. Thus, conservation planning strategies are needed that can focus scarce science resources in ways that maximize the biological benefits of conservation investments to sustain avian populations and their habitats. This process was initiated by reevaluating existing habitat priorities identified in prior IWJV planning efforts.
The IWJV 2005 Coordinated Bird Conservation Plan identified six high priority habitats (Aspen Forest-woodland, Grasslands, Ponderosa Pine Woodland-savanna, Sagebrush Shrubland-steppe, Wetlands) whose ecological extent encompass >191 million acres (or 39%) of the IWJV area. With the goal of informing future science priorities, these six habitat types were examined broadly on the basis of five criteria: 1) habitat extent, 2) habitat diversity and richness, 3) associated bird values, 4) threats, and 5) partner potential.
The majority of these habitat evaluations rely extensively on the ecological systems inventory obtained through NatureServe and derived from the National Vegetation Classification Standard.
- Habitat extent was measured as the area (acres) and landscape pattern type (e.g., patch size) of each priority habitat type and provides insight into potential conservation strategies and challenges.
- Diversity was assessed via Shannon diversity indices calculated from the rate and abundance of ecological systems associated with each habitat type. Wetlands and grasslands contained high habitat diversity scores and habitat richness was well distributed among wetlands, grasslands, and sagebrush shrubland-steppe.
- Bird habitat values were assessed consistent with methods and priority bird species from the 2005 Coordinated Bird Conservation Plan. Wetlands displayed a high habitat value and are the primary habitat for 67% of bird species used in the analysis.
- Threats were evaluated by summarizing private and public landownership rates; distinctively high rates of private landownership were exhibited by wetland (70%) and grassland (50%) habitats.
- Partner potential was measured by summarizing habitat abundance at the state level and considering states with >5% of habitat extent to have high partnership potential. Wetlands ranked 38–62% higher for this category due to their relatively broad distribution in the Intermountain West.
Scores from each of these five assessments were normalized and aggregated into a single model.
Evaluation of scores identified wetlands as a distinctly high priority value. The disproportionally high value for wetland habitat was strongly influenced by high habitat diversity and associated bird values. The distribution of wetlands effectively concentrates biological values in discreet areas due to their limited habitat extent and landscape configurations (i.e., small patch size and linear patterns). This habitat characteristic is consistent with a strategic conservation strategy that must focus limited conservation resources in small areas with the highest potential of biological payoff.
Consequently, wetlands should be considered as the highest priority habitat by the IWJV in both near and long-term planning horizons. These results warrant development of more detailed assessments of wetland habitats to further refine wetland priorities and develop habitat conservation strategies.
Executive Summary of IWJV Technical Plans: