Doctoral Dissertation Research: Modeling the Impact of Urbanization on Ecosystem Services in the Twin Cities of Minnesota

城市发展带来许多好处，如住房和就业机会，但也影响到环境提供包括清洁空气和水在内的生态系统服务的能力。虽然了解城市化如何随时间在多个空间尺度上影响生态系统服务是可持续城市发展的关键一步，但科学认识不足仍然是实现这一目标的主要障碍。明尼苏达双城大学的博士生Adam Berland将在Steven Manson博士的指导下，探索城市化对明尼苏达州明尼阿波利斯市中心城市核心生态系统服务的影响的时空动态。这项研究将沿着一条横断面进行，横断面从明尼阿波利斯市中心的城市核心延伸到郊区到城市边缘，从而捕捉到城市化的一般梯度。这项研究的重点是城市森林，这是城市地区所有树木的统称，以确定以前的土地覆盖变化如何影响城乡梯度上的城市森林，生态系统服务与目前沿城乡梯度分布的城市森林之间的关系，以及预计的城市扩展将如何影响未来几十年的生态系统服务。航空照片将被用来记录过去70年来与土地覆盖过渡有关的样带的森林树冠变化。回归分析将评估树冠覆盖、土地覆盖类型和距城市核心的距离之间的关系，以展示几十年来城市森林覆盖如何随着土地利用的变化而波动，从而为了解当前和未来的城市森林生态系统服务前景提供背景。然后，将根据对300个野外站点的详细植被和土地覆盖调查，确定研究样带目前的生态系统服务的特征。几种建模方法将接近目前城市森林提供的服务，如空气污染清除、雨水拦截和碳储存。最后，将在一系列可能的土地覆盖变化情景下估计未来50年的生态系统服务分布。利用树木年轮和市政种植记录，为样带中最常见的树木建立物种级别的年龄与大小的关系，这项研究将预测树木的生长和生态系统服务提供的相关变化。总之，这些努力将突出研究样带沿线过去、现在和未来的生态系统服务分布。这项研究将通过展示生态系统服务在多个空间尺度上的城乡梯度随时间的分布来解决科学知识中的一个关键差距。考虑到最近区域规模规划的增加，这项研究是及时的，因为它分析了几个城市的情景。项目成果将直接适用于区域土地管理人员和城市森林管理人员，方法是突出生态系统服务的历史得失领域，预测未来土地覆盖变化情景和城市森林管理战略的影响，并预测未来虫害暴发和自然灾害的影响。总之，这些发现将指导当地专业人士在短期和长期努力改善双城大都市区的城市森林生态系统服务供应。

Urban growth generates many benefits such as housing and employment opportunities, but also affects the environment's ability to provide ecosystem services including clean air and water. While knowing how urbanization impacts ecosystem services at multiple spatial scales over time is a critical step in the development of sustainable cities, inadequate scientific understanding remains a primary obstacle to this goal. Doctoral student Adam Berland at the University of Minnesota Twin Cities, under the supervision of Dr. Steven Manson, will explore the spatial and temporal dynamics of urbanization's effects on ecosystem services for an urban core in downtown Minneapolis, MN. The study will take place along a transect that extends from the urban core in downtown Minneapolis through the suburbs to the peri-urban fringe, thus capturing a general gradient of urbanization. The research focuses on the urban forest, a collective term for all trees within the urban area, to determine how previous land cover change has affected the urban forest along an urban-rural gradient, how ecosystem services are associated with the urban forest currently distributed along an urban-rural gradient, and how projected urban expansion will affect ecosystem services in the coming decades. Aerial photographs will be used to document forest canopy change in the transect over the past 70 years with respect to land cover transitions. Regression analyses will assess the relationships among tree canopy cover, land cover type, and distance from the urban core to demonstrate how urban forest cover has fluctuated with land use changes over several decades, thus providing a context for understanding current and future urban forest ecosystem service prospects. Then current ecosystem services in the study transect will be characterized based on detailed vegetation and land cover surveys of 300 field sites. Several modeling approaches will approximate current urban forest provision of services such as air pollution removal, stormwater interception, and carbon storage. Finally, future ecosystem service distributions will be estimated for 50 years under a range of possible land cover change scenarios. Using tree rings and municipal planting records to develop species-level age-to-size relationships for the most common trees in the transect, the study will project tree growth and associated changes in ecosystem service provision. Together, these efforts will highlight past, present, and future ecosystem service distributions along the study transect. This research will address a key gap in scientific knowledge by demonstrating the distribution of ecosystem services along an urban-rural gradient at multiple spatial scales over time. Given recent increases in regional-scale planning, the study is timely because it analyzes scenarios across several municipalities. Project findings will be directly applicable to regional land managers and urban foresters by highlighting areas of historic gains and losses in ecosystem services, projecting the effects of future land cover change scenarios and urban forest management strategies, and projecting the impacts of future pest outbreaks and natural disasters. Together, the findings will guide local professionals in their short- and long-term efforts to improve urban forest ecosystem service provision in the Twin Cities Metropolitan Area.