This geospatial dataset contains North Coast and Cascades Network (NCCN) prairie vegetation monitoring spatial data collected during 2007-2017 at in San Juan Island National Historical Park (SAJH).

The protocol, publications, and all other associated links can be found in the project reference NCCN Monitoring Prairie Vegetation: https://irma.nps.gov/DataStore/Reference/Profile/2193720

Geodatabase feature classes include the original Generalized Random Tessellation Stratified (GRTS) transects, modified active transects selected from the GRTS feature class, and annual segments with associated vegetation data 2007-2009, 2012-2015, and 2017.

The goal of the NCCN prairie monitoring program is to detect and describe changes in the extent and quality of prairie communities in San Juan Island National Historical Park (SAJH). SAJH protects some of the last remaining prairies in Washington state. Over 60% of the American Camp unit is dominated by grasslands that have persisted since the end of the Pleistocene. In 2007, the National Park Service initiated monitoring to document status and trends in cover and ecological condition of vegetation communities using repeatable, rapid assessment of physiognomic class and vegetation quality along line-intercept belt transects.

Transect-based sampling was designed to address a hierarchy of monitoring questions linked to management objectives, including the maintenance of broad landscape structure (e.g., forest versus herbaceous) associated with the cultural landscape and the continued ecological integrity of plant communities. While physiognomic cover is similar today to the historic time period (36% forest:61% non-forest), the ecological condition of grasslands or prairies is threatened by persistent, introduced grasses and exotic shrubs. Monitoring objectives included: 1) detect change in the extent of physiognomic cover types, 2) detect change in the proportion of areas dominated by exotic plant species, 3) detect change in the quality of herbaceous cover types, and 4) detect changes in composition and diversity of herbaceous cover types. Monitoring was implemented at the American Camp unit of SAJH, since 90% of all prairies are located within this section of the park.