A multi-scale approach to assess sage-grouse nesting habitat
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Dan Gibson Erik Blomberg Michael Atamian Jim Sedinger PowerPoint PPT Presentation


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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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Dan Gibson Erik Blomberg Michael Atamian Jim Sedinger

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Dan gibson erik blomberg michael atamian jim sedinger

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

Dan Gibson

Erik Blomberg

Michael Atamian

Jim Sedinger


Overview sage grouse

Overview: Sage-grouse


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


Dan gibson erik blomberg michael atamian jim sedinger

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

  • Ground level vegetation data was collected at nest and random sites

  • ~410 nests


Analyses

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

Temporal

Disturbance

Individual heterogeneity

Analyses


Results

Results

  • 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


  • Dan gibson erik blomberg michael atamian jim sedinger

    Selection versus Survival

    1 denotes spatial selection model

    2 denotes local selection model

    Bold values significant


    Dan gibson erik blomberg michael atamian jim sedinger

    Non-sagebrush shrub cover & Forb cover


    Sagebrush canopy cover

    Sagebrush canopy cover

    * Guidelines to manage sage grouse populations and their habitats

    Connelly et al. 2000


    Grass cover residual grass height

    Grass cover * Residual grass height


    Dan gibson erik blomberg michael atamian jim sedinger

    * Guidelines to manage sage grouse populations and their habitats

    Connelly et al. 2000


    Dan gibson erik blomberg michael atamian jim sedinger

    Pinyon-Juniper encroachment


    Dan gibson erik blomberg michael atamian jim sedinger

    Exotic Grasslands


    Dan gibson erik blomberg michael atamian jim sedinger

    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?


    Elevation slope distance from lek amount of habitat classified as sagebrush 1000m

    Developing a nesting habitat use model

    Elevation * Slope + Distance from lek * Amount of habitat classified as sagebrush (1000m)


    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


    Dan gibson erik blomberg michael atamian jim sedinger

    • 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

    Demographiccontinuity

    Early Brood Rearing

    Nesting

    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


    Dan gibson erik blomberg michael atamian jim sedinger

    • 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:


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