NCCN Monitoring Prairie Vegetation

Boetsch, John

The extent and distribution of prairies, oak woodlands, and forests are important attributes of the San Juan Islands National Historical Park's cultural landscape. Evaluating the quality of these communities is an initial step in the devel¬opment of restoration goals and selection of specific restoration methods. Purpose: Prairies and Garry oak woodlands were once extensive in the lowlands of Washington and Oregon. Today, it is estimated that less than 3% of these areas still exist and many are severely degraded. The goal of the prairie monitoring program is to detect and describe changes in the extent and quality of prairie (herbaceous) communities in San Juan Island National Historical Park. The extent and distribution of prairies, oak woodlands, and forests are important attributes of the park’s cultural landscape. Evaluating the quality of these communities is an initial step in the devel¬opment of restoration goals and selection of specific restoration methods. Objectives: 1. Detect change in the extent of physiognomic cover types within American Camp and English Camp. 2. Detect change in the proportion of areas dominated by exotic and native species within American Camp and English Camp. 3. Detect change in the quality of herbaceous cover types within American Camp and English Camp. 4. Detect changes in composition and diversity of herbaceous cover types within American Camp and English Camp. Prairie monitoring follows a two-stage sampling design; the first stage is designed to detect changes in physiognomic cover classes and the second stage focuses on composition of herbaceous communities. Sampling is conducted along parallel transects drawn at random using a general random tessellation stratified sample (GRTS). Physiognomic cover types and origin of predominant species (i.e. exotic or native) are recorded along transects. Species composition, of herbaceous cover types, is monitored within 1 m2 quadrats located systematically along the transects. Status and trends of cover types are assessed through changes in origin of predominant species, species richness, the floristic quality index (FQI), and changes in species composition. Ecological integrity of cover types is classified as good, caution, or significant concern based on status of the cover types. Trends in predominant species, floristic quality, and extent of cover types are used to describe whether the status of the cover type is stable, improving, or declining. REGARDING items excluded from data collection: Sampling is not conducted in areas dominated by trees or in areas that are not accessible (e.g., thickets, steep cliff areas). The prairie monitoring is conducted between May 1 and mid June. Surveys are timed so that both early season forbs and the grasses are visible. After the transects are surveyed, quadrats are surveyed immediately. Although transect monitoring can be conducted while the grasses are still emerging, cover estimates in the quadrats rely on accurate estimation of cover of all species rather than just a few dominants. Quadrats are monitored before leaves from early lilies have senesced. REGARDING advice/caveats for potential users of the data set: Draft values for the floristic quality index (coefficient of conservatism) were utilized in this draft, but this concept really needs more work and more review by technical experts and resource managers. The thought is that this applied index has quite a bit of potential, but data from the vegetation plots and analysis have been very limited up to this point.

NCCN Monitoring Prairie Vegetation

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