Don Callihan, PhD transitioned to the Advisory Council in 2025 after serving from 2019-2025 as Vice President of Gunpowder Valley Conservancy’s Board of Directors, including the role of Interim Executive Director in 2022. He is a member of GVC’s Education & Restoration Committee. Since retirement from BD Diagnostics in Sparks, MD in 2013, he has focused on the intersection between promoting ecosystem services of native plants in the Northeastern Piedmont Ecoregion, while promoting nonnative invasive species management. He is a Maryland Master Naturalist and currently chairs the Friends of Oregon Ridge Stewardship Committee. He is a member of the Maryland Native Plant Society, Wild Ones Greater Baltimore Chapter, and the Ecological Landscape Alliance. He is active with the Maryland Invasive Species Council and a member of the North American Invasive Species Management Association (NAISMA), where he holds a certificate in Terrestrial Invasive Plant Management. Don lives in Cockeysville, Maryland above the Loch Raven Reservoir and is committed to the health of the forest in subwatersheds feeding this important regional source of drinking water for Baltimore City and County, as well as promoting its significant recreation potential.