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Transcript of Northern Goshawk (Accipiter gentilis laingi) Habitat and ... · PDF file Northern Goshawk...

  • March, 2008 prepared for: The Northern Goshawk Habitat Recovery

    Implementation Group prepared by: Jason R. Smith and Glenn Sutherland, Cortex Consultants Inc.

    Northern Goshawk (Accipiter gentilis laingi) Habitat and Territory Models

    Modelling Methodology and Implementation

    &

    Scenario Results for Coastal British Columbia

    NOTE: This report is a working DRAFT and should be cited and regarded as such. It has undergone an internal review by the Northern Goshawk Recovery Team and Habitat Recovery Implementation Groups, but many requested revisions have not yet been incorporated into the document. It has not undergone an external peer-review and may contain errors and outdated information.

  • Northern Goshawk Habitat and Territory Models Methodology, Implementation, and Scenario Results

    Working Draft – Do not cite or distribute without permission

    March 2008

    Page ii

    Table of Contents

    Table of Contents ........................................................................................................................... ii  List of Figures ....................................................................................................................................... iii  List of Tables ......................................................................................................................................... v 

    Acknowledgements ....................................................................................................................... vi 

    Executive Summary...................................................................................................................... vii 

    1.  Introduction ........................................................................................................................... 1  1.1.  Background ................................................................................................................................ 1  1.2.  Model Overview .......................................................................................................................... 1  1.3.  Study Area Boundaries ............................................................................................................... 2 

    2.  Model Implementation .......................................................................................................... 4  2.1.  Overview ..................................................................................................................................... 4  2.2.  North Coast, South Coast and Vancouver Island Conservation Regions ................................... 5 

    2.2.1.  Habitat Model ................................................................................................................... 5  2.2.2.  Territory Model ................................................................................................................. 8  2.2.3.  Analysis Scenarios ........................................................................................................ 12 

    2.3.  Haida Gwaii Conservation Region ............................................................................................ 12  2.3.1.  Habitat Model ................................................................................................................. 12  2.3.2.  Territory Model ............................................................................................................... 13  2.3.3.  Analysis Scenarios ........................................................................................................ 15 

    2.4.  Model verification ...................................................................................................................... 16 

    3.  Analysis Results ................................................................................................................. 18  3.1.  North Coast Conservation Region ............................................................................................ 18 

    3.1.1.  Nest and Foraging Habitat ............................................................................................. 18  3.1.2.  Territories ...................................................................................................................... 21 

    3.2.  South Coast Conservation Region ........................................................................................... 26  3.2.1.  Nesting and Foraging Habitat ........................................................................................ 26  3.2.2.  Territories ...................................................................................................................... 29 

    3.3.  Vancouver Island Conservation Region ................................................................................... 30  3.3.1.  Nesting and Foraging Habitat ........................................................................................ 30  3.3.2.  Territories ...................................................................................................................... 33 

    3.4.  Haida Gwaii Conservation Region ............................................................................................ 34  3.4.1.  Nesting and Foraging Habitat ........................................................................................ 34  3.4.2.  Territories ...................................................................................................................... 40  3.4.3.  Effects of stochasticity on results ................................................................................... 40 

    4.  Discussion ........................................................................................................................... 42  4.1.  Analysis Results ....................................................................................................................... 42  4.2.  Model design and applicability .................................................................................................. 42  4.3.  Future Work .............................................................................................................................. 45 

  • Northern Goshawk Habitat and Territory Models Methodology, Implementation, and Scenario Results

    Working Draft – Do not cite or distribute without permission

    March 2008

    Page iii

    5.  References ........................................................................................................................... 47 

    Appendix A - Comparison of Approaches to Modelling Territories ........................................ 48  A.1.  Simulation versus simple circles ............................................................................................... 48  A.2.  Current territory model versus 2006 version ............................................................................. 49 

    A.2.1. Overview ........................................................................................................................ 49  A.2.2. Modelling Challenges .................................................................................................... 49  A.2.3. Approaches to address modelling challenges ............................................................... 52 

    Appendix B – Data Assembly ...................................................................................................... 54 

    Appendix C – Definition of Model Parameters .......................................................................... 56 

    Appendix D – Detailed Territory Attributes ................................................................................ 58 

    Appendix E – Supplementary Graphical Results from the Model ........................................... 59 

    List of Figures

    Figure 1: Study area over which habitat and territory models were applied ..................................................... 3  Figure 2: Overview of modelling framework as a “pipeline” .............................................................................. 5  Figure 3: Flowchart of the NOGO habitat model, indicating input layers, output layers and sub-model

    components ............................................................................................................................ 6  Figure 4: Flowchart of iterative packing approach used by the territory model in the North Coast and South

    Coast CRs. .............................................................................................................................. 9  Figure 5:Spatial restrictions on the placement of new nest areas, relative to existing nest areas. ................. 10  Figure 6: Flowchart of sequential packing approach used Haida Gwaii version of the territory model ........... 14  Figure 7: Distributions describing the probability that a new nest area will initiate a given distance away from

    an existing nest area ............................................................................................................. 15  Figure 8: Distribution of nesting habitat in the NCCR for the current landscape (A) and capable habitat (B)

    scenarios. .............................................................................................................................. 19  Figure 9: Distribution of foraging habitat in the NCCR for the current landscape (A) and capable habitat (B)

    scenarios. ..................