PNW 98 Session - Full AbstractsPNW 98 Session - Full AbstractsSphagnum bogs are infrequent and unique peatlands in the Pacific Northwest. That does not, however, mean they have fared better than other wetlands when historical resource loss is concerned. A full 25% of sphagnum bog acreage inventoried within King County in Rigg's Peat Resources of Washington, 1958, were already lost before the book was even published, and many more acres were lost in subsequent years. Most of these losses were due to physical disruption, e.g. mining or draining and conversion to cropland.
What is perhaps surprising is that loss of sphagnum resources is continuing today, even within the current regulatory framework of no net loss. For indeed, it is not the wetland that is lost, but the unique plant community itself. A recent survey of sphagnum bogs in King County revealed a disturbing trend. Five wetlands known to have had significant sphagnum bog components in 1980 had lost those components by 1997: complete loss of the community within 20 years. Many more bogs had suffered serious impacts, with former healthy sphagnum communities invaded by cattail, spirea and other species. Frequently the cause was nothing more exotic than urbanization. The effects of urbanization in degrading sphagnum resources will be briefly summarized.
Benefits of retaining healthy sphagnum bogs include retention of the intrinsic values of these ancient and unique wetlands as well as the prevention of accelerated eutrophication in downstream lakes which occurs when peat decomposition rates increase. To capture these benefits, conservation measures are needed that go beyond "no net loss" and consider the quality of the preserved wetland as well as it's quantity.