Identifying Priority Willamette Valley Oak and Prairie Habitat – Final Phase

In 2006 The Nature Conservancy decided to make use of recent (2005) high resolution natural color National Agriculture Imagery Program (NAIP) imagery to evaluate abundance of oak and prairie habitats on a taxlot basis for selected portions of the Willamette Valley. This project focused on about 25 priority areas identified in TNC’s Willamette Valley-Puget Trough-Georgia Basin ecoregional assessment as important areas for oak habitat conservation. By attributing a GIS shapefile of taxlots (containing location and ownership data) with acres of oak and prairie habitat, we felt we could create a tool that could be used to identify the locations of the largest remaining areas of oak and prairie habitat, as well as identify the owners or managers of the most significant remaining habitats. The taxlots were attributed simply by estimating the percent cover of oak habitat and prairie or other un-managed grassland for each taxlot. The percentages could then be multiplied by the acres of each tax lot to generate acreage estimates. This initial phase was funded through a Landowner Incentive Program (LIP) grant administered by the Oregon Department of Fish and Wildlife. In April 2008 TNC staff gave a presentation on the results of the first phase inventory to the Oregon Oak Working Group at a meeting held in Eugene.