LTER: Dynamic heterogeneity: Investigating causes and consequences of ecological change in the Baltimore urban ecosystem

世界各地的城市人口继续扩大，凸显出对科学信息的日益需要，以加深我们对影响城市生态系统结构和功能的生态和社会因素的了解。需要一套健全的城市社会生态系统理论和模型，以帮助城市适应不断变化的条件，并改善城市本身及其生态足迹腹地的环境质量。此外，了解现有城市和郊区持续变化的驱动因素对于环境可持续性、经济活力和人类福祉都很重要。巴尔的摩生态系统研究(BES)是一个长期的生态研究项目，致力于将马里兰州巴尔的摩大都市作为一个生态系统来理解，并与该市及周边地区的社区、教育工作者和决策者分享关键的生态知识。需要一个长期的方法来理解城市系统，因为1)发生在城市中的许多生态过程，如植物群落、动物多样性和土壤发展的变化，是缓慢的；2)许多改变城市形态和功能的强烈甚至灾难性的事件只发生得很少；3)生态过程和人类行为之间的反馈是在很长一段时间内展开的。经过近20年的集中研究，BES发现了明确的基线，并记录了环境变化的轨迹。这些正在进行的研究记录了关于城市系统功能的令人惊讶的结果，测试或修改了现有的生态模型，并产生了将城市理解为生态系统的新方法。其中许多见解已被纳入K-12和中学后教育的课程和教材。BES开发的新的城市模型和视角已被证明对理解巴尔的摩以外的城市和地区非常重要。BES的根本挑战和使命是理解和发现生物、物理和人类因素如何相互作用，在长期尺度上改变城市生态系统。该项目涉及反映城市生态系统复杂性的三个问题：1)水文学、生态系统养分转化和社会因素如何影响城市流域的营养物质和污染物的传输和保持；2)生物群落的物种组成和结构如何对一系列复杂的生物物理和社会过程作出反应；3)人类对土地管理的选择如何与流域动态和生物群落结构相互作用？这些问题源于生态系统中养分保持的驱动因素、生物多样性和生态系统功能、元群落动态和人类决策的基本理论。BES研究小组将继续收集有关河流和分水岭功能、植物、动物和微生物的生物多样性以及人力资源使用和社会结构的关键长期数据。我们将开发和实施新的空间广泛的实地采样，以提高对1)溪流及其流域之间的空间联系，2)人类管理对植物群落和昆虫群落多样性的作用，以及3)市场和非市场土地使用决策对生态系统过程的影响的知识。我们的总体方法是将所有学科的研究放在三个分水岭上，以促进社会-生态一体化水平，以实现对城市生态系统结构和功能的深入了解。

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.