Assessing national park resource condition along an urban–rural gradient in and around Washington, DC, USA

Managing parks within an urban and urbanizing landscape context is the new normal for the U.S. National Park Service (NPS). The NPS Inventory and Monitoring (I&M) program is tasked with collecting data on the natural resource condition of all 270 parks in the NPS system deemed to have significant natural resources. Synthesizing this large amount of diverse data into comprehensive assessments of ecosystem integrity has proven to be a daunting task. We provide an analysis of NPS I&M data for ten national parks located along an urban–rural gradient from Washington, DC to the Blue Ridge Mountains in the Mid-Atlantic, USA. Twelve representative metrics of ecosystem condition were selected and combined into single park scores using four separate approaches for data aggregation. The different analysis methods were compared based on criteria including the ability to differentiate among parks, sensitivity to uncertainty in assessment points, ability to use varied data sources, and information content for management. The results support the use of relatively simple methods such as distance-based aggregation scoring for long-term assessment of lands in this mixed-used landscape. Land use change within 5-km buffers adjacent to the parks was significantly correlated with overall scores and was a strong predictor of water quality measures. Urban parks generally scored slightly lower than parks located in more rural settings. However, the distance-based method penalized the urban parks less than other scoring approaches for several small problems, and urban parks scored fairly well by this recommended method. Trends in regional land use change should be carefully monitored, but at present, most of the parks along this urban–rural gradient are successfully fulfilling their mission of sustaining natural resources at a high level of ecological integrity.