Martin Lafrenz

Date of Award

Winter 2020

Document Type


Degree Name

Master of Science (M.S.) in Geography



Physical Description

1 online resource (viii, 124 pages)


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-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.

Available for download on Saturday, May 22, 2021

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