A Week’s Worth of Botany on Patos Island

I spent last the past week surveying vegetation on Patos Island, the northernmost island in the San Juan Archipelago. The 200 acre island is owned by the BLM and managed in conjunction with Washington State Parks. Patos is home to one of four lighthouses in the San Juans (two of which are owned by the BLM) which was constructed in 1893 and has since guided ships traveling between the US and Canada. Patos island, called isle de Patos by Spanish explorers, is translated to island of ducks, this name coming from a stone structure closely resembling a duck head and body on the eastern most point of the island.

The Namesake of the island, stone duck at Toe Point, Patos Island.

Patos Island is a popular spot for kayakers and boaters visiting the lighthouse, camping at its 7 pristine campsites, and exploring its 1.5 mile trail around the island.

Boats anchored in Active Harbor, Patos Island

Patos is a charming though challenging spot for a botanist. As one of the wetter sites in the San Juans, it supports a vigorous plant community. It supports novel species that grow only occasionally in other parts of the islands. Among the prettier species are Tiger Lily (Lilium columbianam) White Fawn Lily (Erythronium oregonum), Red Huckleberry (Vaccinium parvifolium), Douglas Maple (Acer glabrum), Paper birch (Betula papyrifera), and Black Cottonwood (Populus tremuloides), Garry Oak (Quercus garryana) and, my favorite, California broomrape (Orobanche California var. californica).

Bluff with Garry Oak, Toe Point, East Patos Island

Patos also has an abundance of plants common elsewhere in the islands. Walking from the shoreline to an interior transect, I was frequently confronted with a wall of shrubs (Salal, Nootka Rose, Baldhip Rose, Trailing Blackberry, and Oceanspray) that was more than 200 meters thick and 3 meters tall. Upon reaching the interior, I found an undergrowth plant community dominated by 2 meter sword fern.

Despite obstacles and shrubbery, I completed 7 transects across the island using the AIM (Assessment, Inventory and Monitoring) strategy. Transects were in woodland, forest, maintained grassland, and coastal bluffs. Outside of my transects, I began a plant list on the island and documented several invasive species that had penetrated the thick forest vegetation. I found a marsh in the middle of the island as well as a garry oak habitat on the eastern shore. Oh, and I took lots of pictures.

I hope everyone is enjoying their internships and the areas they are based out of.

Jennifer McNew