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Dan Gibson Erik Blomberg Michael Atamian Jim Sedinger

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A multi-scale approach to assess sage-grouse nesting habitat Comparing nest site selection and nest success. Dan Gibson Erik Blomberg Michael Atamian Jim Sedinger. Overview: Sage-grouse. Why is knowledge regarding habitat use important?.

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A multi-scale approach to assess sage-grouse nesting habitatComparing nest site selection and nest success

Dan Gibson

Erik Blomberg

Michael Atamian

Jim Sedinger


Why is knowledge regarding habitat use important?

  • Habitat degradation is the primary mechanism driving sage-grouse population declines
  • Habitat will continue to be degraded
  • We need to establish what habitat is important (during various life history stages) for species persistence at multiple scales and manage it appropriately
so what is important habitat
So, what is “important” habitat?
  • Is it being used?
  • Are individuals successful?
  • In theory, the relationship between habitat selection and success compares what habitat features improved fitness along an organism’s evolved life history, and what improves fitness in its current environment
research objectives
Research Objectives
  • Investigate which habitat characteristics sage-grouse are being selecting for as nesting habitat and how they influence nest success
  • Use this information to develop tools to make more informed management decisions

Monitored female sage-grouse from 2003-2012 in Eureka Co. Nevada

  • Ground level vegetation data was collected at nest and random sites
  • ~410 nests
Nest Site Selection (RSF models)

Binomial generalized linear mixed models (GLMM) in R (lme4 package)

Random effects: year and individual

Two independent analyses performed (two scales: “spatial” and “local”

Nest Survival

Nest survival module in Program MARK

Predictor variables

Ground-scale vegetation

Spatial-scale habitat structure



Individual heterogeneity

  • Nest Survival
    • Estimates of overall nest survival were low (17%)
      • Note: It is very difficult to achieve a lambda >1.0 at this level of success
  • Selection
      • Local: selection pressures were the greatest for various forms of cover and forb availability
      • Spatial: provided a mechanism to delineate nesting from available habitat using relatively coarse spatial metrics
  • Very few habitat features were supported to influence both nest selection and nest success

Selection versus Survival

1 denotes spatial selection model

2 denotes local selection model

Bold values significant

sagebrush canopy cover
Sagebrush canopy cover

* Guidelines to manage sage grouse populations and their habitats

Connelly et al. 2000


Summary so far…

  • Very few habitat features exhibited a selective pressure and influenced nest success
  • Current management decisions geared to improve sage-grouse populations through modifying nesting conditions may ultimately not be successful
  • Current guidelines for management of sage-grouse nesting habitat do not appear to be appropriate for central Nevada
  • So, can we develop tools to assist management?
delineation of nesting habitat
Delineation of nesting habitat
  • ~18% of surrounding habitat was classified as suitable which encompassed 75% of nest points
    • Estimate of concordance = 0.72
Independently collected nest locations fit the model well … for the most part
  • Additionally, statewide spring telemetry locations fell within “suitable habitat” at a high rate
demographic continuity

Early Brood Rearing


Late Brood Rearing

  • Establish what habitats are required during “important” life history stages
  • Protect the commonalities
  • Allow for connectivity between stages

Probability of Use

*Atamian et al. 2010

Thanks to:
    • Jim Sedinger, Erik Blomberg, and Mike Atamian
    • Shawn Espinosa, Chet Van Dellan (NDOW) and Peter Coates (USGS)
    • All previous graduate students, technicians, and volunteers that have worked on this project
    • All funding sources: