Large-scale infrastructure development that accompanies global urban transformation threatens biodiversity and ecosystems around the world. Transportation infrastructure, in particular, uniquely affects landscape structure and connectivity. However, spatially explicit, quantitative analyses of change in habitat configuration due to multiple, linked transportation infrastructure are rare. Here, we analyze how a new airport and new highway system altered the spatial pattern of forest habitats to the north of the İstanbul metropolitan region in the context of two-decade-long landscape change. We carry out a land-change analysis from 2000 to 2019. We then analyze the changes in the spatial patterns of various forest habitat types across the metropolitan region, within and in the vicinity of the airport site, and in a key biodiversity area (KBA) that the new highway passes through. New transportation infrastructure significantly altered the forest habitats. Ten percent of all forest cover was lost, a quarter of which due to the new transportation development. Overall and within the KBA, respectively, core forest habitat decreased by 20% and 16%; the share of isolated, highly fragmented, and edge habitats within the remaining forest increased by 7% and 8%. On the European side of the metro area, the last remnants of the connectivity between the western and eastern sections of the forests were lost. The degradation of the forest landscape has implications for the endemic biodiversity and ecosystem services relied on by the metropolitan area. Our findings inform landscape strategies to arrest these degradation trends. Such strategies can succeed if ecological conservation is integrated into planning and current highly centralized governance structure is reformed.

伴随全球城市转型的大规模基础设施开发威胁着世界各地的生物多样性和生态系统。尤其是交通基础设施，对景观结构和连通性有着独特的影响。然而，由于多个相互关联的交通基础设施，对栖息地配置变化的空间明确、定量分析很少见。在这里，我们分析了新机场和新高速公路系统如何在长达两年的景观变化背景下改变了伊斯坦布尔大都市区北部森林栖息地的空间格局。我们进行了 2000 年至 2019 年的土地变化分析。然后我们分析了大都市区、机场场地内和附近的各种森林栖息地类型的空间格局变化，以及新高速公路穿过的关键生物多样性区 (KBA)。新的交通基础设施显着改变了森林栖息地。10% 的森林覆盖消失了，其中四分之一是由于新的交通发展。总体而言，在 KBA 内，核心森林栖息地分别减少了 20% 和 16%；剩余森林中孤立、高度分散和边缘栖息地的比例分别增加了 7% 和 8%。在大都市区的欧洲一侧，森林西部和东部部分之间的连通性的最后残余已经丢失。森林景观的退化对大都市区所依赖的地方性生物多样性和生态系统服务产生了影响。我们的研究结果为景观策略提供了阻止这些退化趋势的信息。