Wildlife Connectivity Modeling for the Northern Red-Legged Frog in the Portland Metropolitan Area, Oregon" (2020)
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Portland State University PDXScholar Dissertations and Theses Dissertations and Theses 5-22-2020 Wildlife Connectivity Modeling for the Northern Red- legged Frog in the Portland Metropolitan Area, Oregon Amanda Hilary Temple Portland State University Follow this and additional works at: https://pdxscholar.library.pdx.edu/open_access_etds Part of the Geography Commons Let us know how access to this document benefits ou.y Recommended Citation Temple, Amanda Hilary, "Wildlife Connectivity Modeling for the Northern Red-legged Frog in the Portland Metropolitan Area, Oregon" (2020). Dissertations and Theses. Paper 5432. https://doi.org/10.15760/etd.7305 This Thesis is brought to you for free and open access. It has been accepted for inclusion in Dissertations and Theses by an authorized administrator of PDXScholar. Please contact us if we can make this document more accessible: [email protected]. Wildlife Connectivity Modeling for the Northern Red-legged Frog in the Portland Metropolitan Area, Oregon by Amanda Hilary Temple A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Geography Thesis Committee: Martin Lafrenz, Chair Catherine de Rivera Geoffrey Duh Portland State University 2020 © 2020 Amanda Hilary Temple i Abstract Effective habitat connectivity tools that use GIS data perform well in remote areas but may not be as dependable in urban environments. My goal was to study uses and limitations of a conservation management tool in development, the Metro Regional Habitat Connectivity Toolkit, which evaluates connectivity for and permeability of wildlife movement. Habitat quality scores are generated from GIS-derived and field collected data such as connectivity patch/matrix characteristics, water source, vegetation, other structural components, wildlife observations, and human disturbance at survey sites. I compared GIS and field generated habitat quality scores for the Northern Red- legged Frog (Rana aurora) in urbanizing Gresham East Buttes, Oregon. Using Spearman’s ranked correlation, there was low positive correlation between GIS and field scores indicating the two scores assess different types of data. The magnitude of difference between these scores had no interdependence along a development gradient. Assessment of Northern Red-legged Frog locations in Forest Park, resulted in habitat quality scores which were sensitive to the presence or visibility of water sources and other structural components such as woody debris. These findings indicate the need for repeat field surveys, and the importance of field-collected data’s unique contributions which ensure crucial wildlife dispersal is protected in rapidly changing environments. To give regional conservation managers confidence in applying connectivity tools in urbanizing environments, I compared a predictive Circuitscape connectivity model to additional field collected data such as habitat quality, and distance between aquatic- ii terrestrial habitats using aquatic egg mass surveys for Northern Red-legged Frog. Further genetic and demographic studies are recommended to fully discern the implications of these findings and to protect this Oregon state strategy species that utilizes at-risk aquatic and terrestrial connections during its annual migrations. iii Acknowledgements Research support, encouragement, and countless feedback from faculty Martin Lafrenz, Catherine de Rivera, Leslie Bliss-Ketchum, Geoffrey Duh, David Banis Field surveying, data entry, or radio-telemetry monitoring assistance from Jesse, Lita, Alex, Jim, Amber, Jeffrey, Brian, Sara, Corrine and additional volunteers Permitting and site access from Harborton Frog Shuttle, PSU-IACUC, Oregon Department of Fish and Wildlife, City of Portland Department of Parks and Recreation-Forest Park, City of Gresham, Nolan J. Additional feedback and correspondence from all the frog fans out there Katie H., Lauren C., Laura G., Sue. B., Lori H., Meghan G., Katie W., Marc H., Kelly L., Elke W., Lisa H., Jakob D. Funding from Metro Regional Government, Bullitt Foundation, Oregon Wildlife Foundation Portland State University Larry and Nancy Price Field Work Grant William and Edith Rockie Scholarship Thank you to my family and loved ones for supporting me iv Table of Contents Abstract ............................................................................................................................... i Acknowledgements ........................................................................................................... iii List of Tables ................................................................................................................... vii List of Figures ................................................................................................................. viii ❖ Chapter 1 Connectivity Literature Review and Tool Development 1. Introduction ..................................................................................................................1 2. Research Objectives .....................................................................................................2 3. What is Connectivity? ..................................................................................................5 4. Regional Connectivity Strategies .................................................................................7 5. Urbanizing Places for Wildlife ....................................................................................9 6. Connectivity Modeling Tools ....................................................................................11 7. Metro Regional Habitat Connectivity Toolkit Development.....................................13 ❖ Chapter 2 Evaluation of Metro Toolkit Habitat Quality Scorecard: Case Study Northern Red-legged Frog (Rana aurora) 1. Background ................................................................................................................15 2. Sites ............................................................................................................................17 3. Methods 3.1 Habitat Connectivity Zones ...............................................................................21 3.2 GIS and Field Data Collection ...........................................................................25 3.3 Species Scorecard ..............................................................................................26 v 3.4 Comparison between GIS and Field Scores.......................................................27 4. Results 4.1 GIS and Field Data Habitat Quality Score .........................................................28 4.2 Differences Between GIS and Field Scores Along Development Gradient ......29 5. Discussion ..................................................................................................................32 ❖ Chapter 3 Sensitivity Analysis in the Field: Case Study Northern Red-legged Frog (Rana aurora) 1. Background ................................................................................................................35 2. Sites ............................................................................................................................37 3. Methods 3.1 Forest Park Survey Sites ....................................................................................41 3.2 Scorecard Sensitivity of Field Collected Habitat Characteristics ......................41 4. Results ........................................................................................................................42 5. Discussion ..................................................................................................................43 ❖ Chapter 4 Applications of Metro Regional Habitat Connectivity Toolkit for Conservation Managers: Case Study Northern Red-legged Frog (Rana aurora) 1. Background 1.1 Need for Northern Red-legged Frog Connectivity Tools ..................................45 1.2 Circuitscape Uses and Limitations.....................................................................48 2. Applications ...............................................................................................................49 vi ❖ Chapter 5 Conclusions and Future Research Recommendations 1. Conclusions ................................................................................................................65 2. Future Research Recommendations 2.1 Monitoring Amphibian Habitat and Movement ................................................66 2.2 Urban Habitat Connectivity Management .........................................................69 References ..........................................................................................................................73 Appendix A: Glossary........................................................................................................85 Appendix B: Forms ..........................................................................................................100 Appendix C: Additional Data ..........................................................................................106 Appendix D: Forest Park Radio-telemetry Data ..............................................................113 vii List of Tables Table 1. Thesis Research Objectives ...................................................................................3 Table 2. Urban Habitat Connectivity Management ...........................................................52 Table 3. Priority Connectivity in Gresham East