Urban populations continue to expand around the world, highlighting the growing need for scientific information to deepen our understanding of ecological and social factors that influence the structure and function of urban ecosystems. A robust set of theories and models of cities as social-ecological systems is necessary to help cities adapt to changing conditions, and improve environmental quality both within cities themselves, and in the hinterlands that lie within their ecological footprints. In addition, knowledge of the drivers of ongoing changes within existing cities and suburbs are important for environmental sustainability, economic vitality, and human well-being. The Baltimore Ecosystem Study (BES) is a Long-Term Ecological Research project that is committed to understanding metropolitan Baltimore, MD, as an ecological system, and to sharing crucial ecological knowledge with communities, educators, and decision makers in the city and surrounding regions. A long-term approach to understanding urban systems is required because 1) many ecological processes that occur in cities, such as changes in plant communities, animal diversity, and soil development, are slow, 2) many of the intense and even catastrophic events that change city form and function occur only infrequently, and 3) the feedbacks between ecological processes and human actions unfold over long-time periods. BES has discovered clear baselines and has documented trajectories of environmental change over nearly two decades of concentrated research. These ongoing studies have documented surprising results about the functioning of urban systems, tested or modified existing ecological models, and generated new ways to understand the city as an ecosystem. Many of these insights have been incorporated into curricula and educational materials for K-12 and post-secondary education. The new urban models and perspectives developed in BES have proven to be important for understanding cities and regions well beyond Baltimore.
The fundamental challenge and mission of BES is to understand and discover how biological, physical, and human factors interact to change urban ecosystems over long time scales. The project addresses three questions that reflect the complex nature of urban ecosystems: 1) How do hydrology, ecosystem nutrient transformations, and social factors affect transport and retention of nutrients and contaminants by urban watersheds; 2) How do species composition and structure of biological communities respond to a complex set of biophysical and social processes; and 3) How do human choices about land management interact with watershed dynamics and the structure of biological communities? These questions emerge from fundamental theories of the drivers of nutrient retention in ecosystems, biodiversity and ecosystem function, metacommunity dynamics and human decision-making. The BES research team will continue to collect key long-term data on stream and watershed function, the biodiversity of plants, animals, and microbes, and human resource use and social structure. We will develop and implement new spatially extensive field sampling to improve knowledge about 1) the spatial linkages between streams and their watersheds, 2) the role of human management on diversity in plant and insect communities, and 3) the impact of both market and non-market land use decisions on ecosystem processes. Our overall approach is to co-locate research across all disciplines on three watersheds to facilitate the level of social-ecological integration necessary to achieve deep understanding of urban ecosystem structure and function.
