Pollinator Recovery on Portland's Superfund Shoreline:
Tracking Bombus vosnesenskii at the University of Portland

The Portland Harbor Superfund Site encompasses a 10-mile stretch of the lower Willamette River contaminated by over a century of industrial activity - including shipyards, manufacturing, and chronic urban stormwater runoff. Sediments and soils along this corridor are heavily tainted with polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), heavy metals, and other persistent organic pollutants that accumulated from the late 19th century through the 20th century.

The University of Portland's river-facing property sits directly on this contaminated corridor. In 2006, the university entered into a formal agreement with the EPA to assess and plan remediation of legacy soil and groundwater pollution along the riverbank. Major active remediation - including contaminated soil excavation, heavy metals and PCBs removal, and riverbank capping to prevent further runoff - took place between 2012 and 2014.

Following remediation, the university developed the Franz River Campus, now home to the E.L. Wiegand Environmental Lab, the university boathouse, and restored riparian plantings along the Willamette shoreline. By 2026, the site has had approximately 12 years to begin ecological recovery since active remediation.

This question is addressed through individual bee tracking at both sites simultaneously. By tagging bees captured at the Franz River Campus (lower campus, river's edge) and at the SLUG community garden (upper campus), we can determine:

A secondary question addresses whether the Franz River Campus riparian corridor is supporting a self-sustaining B. vosnesenskii population 12 years after active remediation, or whether bee presence is primarily driven by movement from established upper campus habitats.

The two sites are separated by approximately 0.25 miles and 180 feet of elevation change - a topographic gradient that adds ecological significance to any confirmed inter-site movement, as bees navigating this corridor must traverse both built campus infrastructure and significant elevation.

Documenting native pollinator recovery at a Superfund remediation site addresses a significant gap in restoration ecology literature. While vegetation recovery following contaminated site remediation is well-studied, invertebrate and pollinator recolonization timelines are far less documented - particularly in urban riparian environments.

The Franz River Campus setting is ecologically unusual: a remediated industrial shoreline embedded within an active university campus, adjacent to both the Willamette River and a productive student-managed food garden. This configuration allows direct comparison of pollinator activity between a recovering contaminated site and an established urban agricultural habitat within the same landscape.

Findings from this study have direct relevance for:

• EPA and regulatory assessment of biological recovery indicators at Superfund sites
• Urban pollinator conservation planning in Portland and similar post-industrial cities
• University sustainability and campus ecology programs
• Restoration practitioners seeking native pollinator recolonization benchmarks
• Future grant applications to USDA NIFA, NFWF, and EPA STAR programs

This project is led by Dr. Tara Prestholdt of the University of Portland Biology Department and the Summer Undergraduate Research Experience. Student researchers manage daily station deployment, bee capture and tagging, data collection, and station maintenance under faculty supervision.

Student involvement spans hardware assembly, ecological field protocols, data management, and statistical analysis - providing genuine hands-on experience in restoration ecology research methods, embedded systems, and scientific computing. The project connects Biology, Environmental Science, and the university's sustainability mission through a real-world research problem with publication-quality outcomes.