Duncans Mills Marsh

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Duncans Mills Marsh

Of the various freshwater marshes that occur along the lower reaches of the Russian River this is unique. On all but the southern edge it is bordered by a redwood, Sequoia sempervirens, forest with associated vegetation which includes California laurel, Umbellularia californica, and Oregon ash, Fraxinus latifolia.

One of the most numerous and obvious plants in the marsh is the yellow pond-lily, Nuphar luteum ssp. polysepalum, which covers most of the surface except at the northern end, where the cattail, Typha latifolia, dominates, and at the southern end, where it yields to the cattail and the pondweed, Potamogeton natans, water buttercup, Ranunculus aquatilis var. hispidulus, and duckweed, Lemna minima. Along the margins of the pond the sedge, Carex obnupta, bulrush, Scirpus acutus, and the water plantains, Alisma plantago-aquatica and the non-native Alisma lanceolatum, are in abundance. The circumboreal but uncommon mare's tail, Hippuris vulgaris, occurs on the west side of the marsh. Both the coastal rush, Juncus effusus var. brunneus, and the inland rush, Juncus effusus var. pacificus, are found here, as is the spreading rush, Juncus patens. The bur-weed, Sparganium emersum ssp. emersum, reaches its extreme southern limit on the Pacific Coast in this marsh.

In the adjacent redwood forest the ground cover includes, among other plants, wild ginger, Asarum caudatum, redwood violet, Viola glabella, star-flower, Trientalis latifolia, redwood sorrel, Oxalis oregana, and fetid adder's tongue, Scoliopus bigelovii. Three sedges grow on the forest floor, Carex hendersonii, rare in this portion of the State, Carex deweyana ssp. leptopoda, and Carex bolanderi. Two rare plants are found in the area, Alopecurus aequalis var. sonomensis and Campanula californica.

The marsh is quite rich in animal life, with the birds most conspicuous. Over 100 species have been sighted here; among the more noteworthy are the wood duck, Aix sponsa, Virginia rail, Rallus limicola, American bittern, Botaurus lentiginosus, and the osprey, Pandion haliaetus. There are various herptiles present, including the Western pond turtle, Clemmys marmorata, and a population of the Pacific giant salamander, Dicamptodon ensatus.

Integrity: Undeveloped except for a few bird nesting boxes and the trail which skirts the pond.

Use: Private.

Ref: Knight, Walter, 1972. An Evaluation of Duncans Wills Pond-marsh. Calif. Native Plant Soc. Newsletter Vol. VII, No. 4, pp. 8-9.

February 1976