Colonial National Historical Park natural resource condition assessment: Virginia

Lookingbill, Todd; Bentsen, Cahterine; Carruthers, Tim; Costanzo, Simon; Dennison, William; Doherty, Carolynn; Lucier, Sarah; Mardon, Justin; Poppell, Ericka; Saxby, Tracey

Colonial National Historical Park crosses four counties with adjacent land owned by the U.S. Navy, U.S. Coast Guard, Cities of Newport News and Williamsburg, the Colonial Williamsburg Foundation, College of William and Mary, and private landowners. These adjacent areas are experiencing rapid development and expansion of commercial, single and multi-family residential properties, while agriculture and silviculture land uses decline throughout the Park’s watersheds. The geography of the Park is important to consider in interpreting the assessment results. The Park stretches between two large rivers, the James and the York, with significant shoreline along each. The location of the Park is within a dynamic tidal region of these water bodies. In 1985, a northeaster destroyed the Yorktown waterfront pier and docks, and required the addition of beach fill and a breakwater to stabilize the shoreline. In 2003, Hurricane Isabel storm surge damaged shoreline stabilization structures, eroded beaches, washed away several archeological sites along the Parkway and on Jamestown Island, and severely damaged the Jamestown visitor center and several tour road bridges. These extreme events are compounded by local eustatic sea level rise of 2.1 millimeters (0.1 inches) per year. This assessment includes few metrics designed specifically to gauge the effects of storm surge and climate-driven fluctuations in water level. However, these effects were captured indirectly within the current assessment framework, for example in measures of water quality, species invasions, and changes in vegetation composition. It is recommended that critical data gaps can be resolved by measuring indices like shoreline erosion, tidal marsh elevation change, changes in salinity regime, or other indices which can directly describe how these two rivers impact the Park and its resources. The combined natural resources of Colonial NHP were assessed as on the border between “degraded” and “fair”, attaining 40% of desired threshold scores. Three of the four habitats assessed (grassland, non-tidal wetland, and tidal wetland) achieved less than 50% attainment, while forest habitat attained a score of 58%. Due to deficiencies in the extent and quality of available data, confidence in the accuracy of this assessment is limited and highlights the need for more targeted data collection activities based on the metrics and habitats described in this assessment. Forest condition assessment was “fair” despite very good attainment of threshold scores for forest interior dwelling bird diversity (including sensitive and very sensitive species), the percentage of forest cover, and the amount of impervious surface. The “fair” rating for forest habitat was primarily due to very degraded, but improving, air quality (ozone). The assessment for forest would likely be worse if deer populations were used as a metric as they are considered to be at unsustainable levels, however, population monitoring data was unavailable. Warm-season grasslands were assessed as “fair,” with very good contiguous grassland areas (four grassland patches > 20 hectares [49 acres] in size) and improving grassland management practices, but low mammal and bird diversity, and widespread invasive plant species (particularly in Yorktown). Non-tidal wetland condition was assessed as “degraded” due to widespread invasive plant species, poor Lepidoptera and Odonata richness and a very degraded index of biotic integrity for the benthos, based on limited available data. Non-tidal wetland did, however, have a fair-to-good diversity of herpetofauna (including uncommon and very rare species) that contributed to this habitat not receiving a “very degraded” condition assessment. Tidal wetland condition was also assessed as “degraded”, due to widespread invasive plant species and a fair condition of submerged aquatic vegetation, water quality, and benthic index of biotic integrity.

Colonial National Historical Park natural resource condition assessment: Virginia

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