Antietam National Battlefield natural resource condition assessment: National Capital Region

Thomas, Jane; Calzarette, Joe; Campbell, J.; Carruthers, Tim; Cohen, Debbie; Dennison, William (Bill); Donaldson, Lindsay; Landsman, Andrew; Lehman, Mark; Nortrup, Megan; Wenschhof, Ed

The lands within Antietam National Battlefield are much as they were on the day of the battle and the park is charged with maintaining them in historical land use to preserve the view of the battle. The first step in framing this Natural Resource Condition Assessment was to define the key habitats within the park. Habitats ‘managed for natural resource values’ were the natural habitats (forests, wetlands and waterways, warm-season grasslands) and were assessed for ecological value, while habitats ‘managed for agricultural values’ (croplands and pastures) were assessed for being the most ecologically sustainable croplands and pastures possible. Patches of forest within Antietam National Battlefield are well connected; however, forest interior area is small, providing moderate habitat potential for native fauna, including forest interior dwelling bird species. It is recommended to preserve this forest structure by limiting future fragmentation and minimizing stresses to forest areas. Very high deer populations are present within forest areas, resulting in limited regeneration capacity, as well as trampling, overgrazing, and reduction of habitat value for wildlife. It is recommended to implement deer reduction strategies. The abundant presence of exotic plant species displaces native species and reduces habitat value. Continued early detection of exotic species is recommended with subsequent active control measures. Assessment of exotic species cover would be better assessed with park-wide mapping as the current small number of plots is not ideal for assessing exotic species cover on a park scale. Wetland and waterway habitats show no sign of acidification or low oxygen; however, high salinity and nutrients indicate degraded habitat value which is reflected in the regionally low diversity of benthos and fishes. The karst geology of Antietam and the surrounding landscape has implications for water quality of the streams within the park, affecting acid neutralizing capacity, temperature, and salinity of the waterways. It is recommended to identify and work with partners to reduce non-point source nutrient inputs from the watershed, as well as continue to implement (and begin to monitor) best management practices in agricultural lands. Additionally, efforts should continue to establish riparian buffers where appropriate, in consideration of cultural resources and historic vistas. Assessment of these habitats could be improved by inclusion of metrics indicative of groundwater condition, to better understand the effects of the karst geology of the area. It is recommended to carry out baseline grassland plant inventories and optimize fire management to assist a transition to a greater proportion of native warm-season grasses. Warm-season grassland areas are currently not contiguous, limiting the habitat value to wildlife. It is recommended to remove tree lines and expand areas of native grasses where historically appropriate. Future assessments of natural resource condition would be improved by developing inventories and monitoring of bird, small mammal, and insect communities within native grassland habitats. Direct measures of the species and habitat diversity (i.e., range of successional stages) would also be beneficial in managing to maximize habitat value of warm-season grassland habitat.

Antietam National Battlefield natural resource condition assessment: National Capital Region

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