US cities can manage national hydrology and biodiversity using local infrastructure policy

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 114; no. 36; pp. 9581 - 9586
• Main Authors: McManamay, Ryan A., Nair, Sujithkumar Surendran, DeRolph, Christopher R., Ruddell, Benjamin L., Morton, April M., Stewart, Robert N., Troia, Matthew J., Tran, Liem, Kim, Hyun, Bhaduri, Budhendra L.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 05.09.2017; Proceedings of the National Academy of Sciences
• Series: From the Cover
• Subjects: Animals; Anthropogenic factors; Aquatic ecosystems; Aquatic Organisms; Biodiversity; Boundaries; Cities; Conservation of Natural Resources - legislation & jurisprudence; Crayfish; Ecosystem; electricity; ENERGY PLANNING, POLICY, AND ECONOMY; energy–water nexus; Environment; Environmental impact; Environmental Policy - legislation & jurisprudence; Environmental quality; ENVIRONMENTAL SCIENCES; Extinct species; Human influences; Humans; hydrologic alteration; Hydrology; Hydrology - legislation & jurisprudence; Indigenous species; Infrastructure; Physical Sciences; Power consumption; River basins; Rivers; Streams; Studies; United States; urban ecology; urban sustainability; Utilities; United States > US; electricity; urban sustainability; energy–water nexus; hydrologic alteration; urban ecology
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1706201114

Cities are concentrations of sociopolitical power and prime architects of land transformation, while also serving as consumption hubs of “hard” water and energy infrastructures. These infrastructures extend well outside metropolitan boundaries and impact distal river ecosystems. We used a comprehensive model to quantify the roles of anthropogenic stressors on hydrologic alteration and biodiversity in US streams and isolate the impacts stemming from hard infrastructure developments in cities. Across the contiguous United States, cities’ hard infrastructures have significantly altered at least 7% of streams, which influence habitats for over 60% of North America’s fish, mussel, and crayfish species. Additionally, city infrastructures have contributed to local extinctions in 260 species and currently influence 970 indigenous species, 27% of which are in jeopardy. We find that ecosystem impacts do not scale with city size but are instead proportionate to infrastructure decisions. For example, Atlanta’s impacts by hard infrastructures extend across four major river basins, 12,500 stream km, and contribute to 100 local extinctions of aquatic species. In contrast, Las Vegas, a similar size city, impacts <1,000 stream km, leading to only seven local extinctions. So, cities have local policy choices that can reduce future impacts to regional aquatic ecosystems as they grow. By coordinating policy and communication between hard infrastructure sectors, local city governments and utilities can directly improve environmental quality in a significant fraction of the nation’s streams reaching far beyond their city boundaries.