VEGETATION MANAGEMENT IN COASTAL DUNES

Much of the coastal dune landscape lying west of Highway 101 between Heceta Head and Coos Bay is publicly owned, and is managed by the U.S. Forest Service (USFS) or the Bureau of Land Management (BLM). Major efforts to stabilize areas of open dunes with the non-native European beach-grass (Ammophila arenaria) and scotch broom (Cytisus scoparius) began in the late 1940s. Over the last 40 to 50 years, the rapid spread of European beach-grass has led to the vegetative stabilization of hundreds of acres of open sand. Fore-dunes anchored by Ammophila arenaria have grown to several times the height of their ancestors, which were anchored by driftwood and American dune-grass (Elymus mollis). Today, streams flow across the beach through narrow channels in the tall foredunes, not the broad, meandering plain flanked by low, open-sand foredunes. These broad open-sand areas were habitat for the Western snowy plover (Charadrius alexandrinus spp.) and pink sandverbena (Abronia umbellata spp.), both of which are US Fish and Wildlife Service-listed species.

The Forest Service has recently begun experimental efforts in two areas to recreate open sand habitat for these species by mechanically rounding the foredune surface and burying the European beach-grass. Prevailing summer and winter winds have moved sand eastward at approximately 0.6 meters/year into seasonal wetlands vegetated with Carex spp. A small volume of sand is moving northerly at approximately 3 meters/year at one site. New European beach-grass sprouts in the treated areas are pulled by hand to prevent spreading. Three Western snowy plover pairs established successful nests at one site the first year after mechanical treatment; two pairs nested the second season. Efforts to establish pink sandverbena have not yet begun. Future projects to control European beach-grass are being planned in other areas identified as historic habitat for the two listed species. Methods to economically treat large areas without using herbicides have not been found.