Effects of Gunnison Sage-Grouse habitat treatment efforts on associated avifauna and vegetation structure

Translated title of the contribution: Effects of Gunnison Sage-Grouse habitat treatment efforts on associated avifauna and vegetation structure

Paul M. Lukacs, Amy Seglund, Steve Boyle

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Conservation efforts over the last 20 years for the Gunnison Sage-Grouse (Centrocercus minimus) have involved extensive habitat manipulations done predominantly to improve brood rearing habitat for the grouse. However, the effects of Gunnison Sage-Grouse habitat treatments on sympatric avifauna and responses of vegetation to manipulations are rarely measured, and if they are, it is immediately following treatment implementation. This study examined the concept of umbrella species management by retrospectively comparing density and occupancy of eight sagebrush associated songbird species and six measures of vegetation in treated and control sites. Our results suggested that songbird densities and occupancy changed for birds at the extreme ends of their association with sagebrush and varied with fine-scale habitat structure. We found Brewer’s Sparrows (Spizella breweri) decreased in density on treated sites and Vesper Sparrows (Pooecetes gramineus) increased. Occupancy estimation revealed that Brewer’s Sparrows and Green-tailed Towhees (Pipilo chlorurus) occupied significantly fewer treated points whereas Vesper Sparrows occupied significantly more. Vegetation comparisons between treated and control areas found shrub cover to be 26% lower in treated sites. Lower shrub cover in treated areas may explain the differences in occupancy and densities of the species sampled based on known habitat needs. The fine-scale analysis showed a negative relationship to forb height and cover for the Sage Sparrow (Amphispiza belli) indicating, from vegetation measures showing grass and forb cover during a good precipitation year covered significantly more area in the treatment than the control sites, that Sage Sparrows may also not respond favorably to Gunnison Sage-Grouse habitat treatments. While the concept of an umbrella species is appealing, evidence from this study suggests that conservation efforts aimed at the Gunnison Sage-Grouse may not be particularly effective for conserving other sagebrush obligate species of concern. This is probably due to Gunnison Sage-Grouse habitat management being focused on the improvement of brood rearing habitat which reduces sagebrush cover and promotes development of understory forbs and grasses.

    Translated title of the contributionEffects of Gunnison Sage-Grouse habitat treatment efforts on associated avifauna and vegetation structure
    Original languageEnglish
    JournalAvian Conservation and Ecology
    Volume10
    Issue number2
    DOIs
    StatePublished - Dec 2015

    Keywords

    • Colorado
    • Distance sampling
    • Gunnison Sage-Grouse
    • Habitat treatments
    • Occupancy
    • Sagebrush
    • Sagebrush obligates
    • Umbrella species

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