Impacts, Risks, and Adaptation in the United States: Fourth National Climate Assessment, Volume II 7 Ecosystems, Ecosystem Services, and Biodiversity Federal Coordinating Lead Authors Chapter Leads Shawn Carter Douglas Lipton U.S. Geological Survey National Oceanic and Atmospheric Jay Peterson Administration National Oceanic and Atmospheric Administration Madeleine A. Rubenstein U.S. Geological Survey Sarah R. Weiskopf U.S. Geological Survey Chapter Authors Lisa Crozier Roldan Muñoz National Oceanic and Atmospheric Administration National Oceanic and Atmospheric Administration Michael Fogarty Rajendra Poudel National Oceanic and Atmospheric Administration National Oceanic and Atmospheric Administration Sarah Gaichas Michelle D. Staudinger National Oceanic and Atmospheric Administration U.S. Geological Survey Kimberly J. W. Hyde Charles Stock National Oceanic and Atmospheric Administration National Oceanic and Atmospheric Administration Toni Lyn Morelli Laura Thompson U.S. Geological Survey U.S. Geological Survey Jeffrey Morisette Robin Waples U.S. Department of the Interior, National Invasive National Oceanic and Atmospheric Administration Species Council Secretariat Jake F. Weltzin Hassan Moustahfid U.S. Geological Survey National Oceanic and Atmospheric Administration Review Editor Gregg Marland Appalachian State University Recommended Citation for Chapter Lipton, D., M.A. Rubenstein, S.R. Weiskopf, S. Carter, J. Peterson, L. Crozier, M. Fogarty, S. Gaichas, K.J.W. Hyde, T.L. Morelli, J. Morisette, H. Moustahfid, R. Muñoz, R. Poudel, M.D. Staudinger, C. Stock, L. Thompson, R. Waples, and J.F. Weltzin, 2018: Ecosystems, Ecosystem Services, and Biodiversity. In Impacts, Risks, and Adaptation in the United States: Fourth National Climate Assessment, Volume II [Reidmiller, D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. Maycock, and B.C. Stewart (eds.)]. U.S. Global Change Research Program, Washington, DC, USA, pp. 268–321. doi: 10.7930/NCA4.2018.CH7 On the Web: https://nca2018.globalchange.gov/chapter/ecosystems Impacts, Risks, and Adaptation in the United States: Fourth National Climate Assessment, Volume II 7 Ecosystems, Ecosystem Services, and Biodiversity Key Message 1 Kodiak National Wildlife Refuge, Alaska Impacts on Species and Populations Climate change continues to impact species and populations in significant and observable ways. Terrestrial, freshwater, and marine organisms are responding to climate change by altering individual characteristics, the timing of biological events, and their geographic ranges. Local and global extinctions may occur when climate change outpaces the capacity of species to adapt. Key Message 2 Impacts on Ecosystems Climate change is altering ecosystem productivity, exacerbating the spread of invasive species, and changing how species interact with each other and with their environment. These changes are reconfiguring ecosystems in unprecedented ways. Key Message 3 Ecosystem Services at Risk The resources and services that people depend on for their livelihoods, sustenance, protection, and well-being are jeopardized by the impacts of climate change on ecosystems. Fundamental changes in agricultural and fisheries production, the supply of clean water, protection from extreme events, and culturally valuable resources are occurring. 7 | Ecosystems, Ecosystem Services, and Biodiversity Key Message 4 Challenges for Natural Resource Management Traditional natural resource management strategies are increasingly challenged by the impacts of climate change. Adaptation strategies that are flexible, consider interacting impacts of climate and other stressors, and are coordinated across landscape scales are progressing from theory to application. Significant challenges remain to comprehensively incorporate climate adaptation planning into mainstream natural resource management, as well as to evaluate the effectiveness of implemented actions. Executive Summary Biodiversity—the variety of life on Earth—pro- economies, and well-being. Both human and vides vital services that support and improve natural systems respond to change, but their human health and well-being. Ecosystems, ability to respond and thrive under new condi- which are composed of living things that tions is determined by their adaptive capacity, interact with the physical environment, provide which may be inadequate to keep pace with numerous essential benefits to people. These rapid change. Our understanding of climate benefits, termed ecosystem services, encom- change impacts and the responses of biodiver- pass four primary functions: provisioning sity and ecosystems has improved since NCA3. materials, such as food and fiber; regulating The expected consequences of climate change critical parts of the environment, such as water will vary by region, species, and ecosystem quality and erosion control; providing cultural type. Management responses are evolving as services, such as recreational opportunities new tools and approaches are developed and and aesthetic value; and providing supporting implemented; however, they may not be able services, such as nutrient cycling.1 Climate to overcome the negative impacts of climate change poses many threats and potential change. Although efforts have been made disruptions to ecosystems and biodiversity, since NCA3 to incorporate climate adaptation as well as to the ecosystem services on which strategies into natural resource management, people depend. significant work remains to comprehensively implement climate-informed planning. This Building on the findings of the Third National chapter presents additional evidence for Climate Assessment (NCA3),2 this chapter pro- climate change impacts to biodiversity, eco- vides additional evidence that climate change systems, and ecosystem services, reflecting is significantly impacting ecosystems and increased confidence in the findings reported biodiversity in the United States. Mounting evi- in NCA3. The chapter also illustrates the com- dence also demonstrates that climate change plex and interrelated nature of climate change is increasingly compromising the ecosystem impacts to biodiversity, ecosystems, and the services that sustain human communities, services they provide. U.S. Global Change Research Program 270 Fourth National Climate Assessment 7 | Ecosystems, Ecosystem Services, and Biodiversity Climate Change, Ecosystems, and Ecosystem Services Climate and non-climate stressors interact synergistically on biological diversity, ecosystems, and the services they provide for human well-being. The impact of these stressors can be reduced through the ability of organisms to adapt to changes in their environment, as well as through adaptive management of the resources upon which humans depend. Biodiversity, ecosystems, ecosystem services, and human well-being are interconnected: biodiversity underpins ecosystems, which in turn provide ecosystem services; these services contribute to human well-being. Ecosystem structure and function can also influence the biodiversity in a given area. The use of ecosystem services by humans, and therefore the well-being humans derive from these services, can have feedback effects on ecosystem services, ecosystems, and biodiversity. From Figure 7.1 (Sources: NOAA, USGS, and DOI). U.S. Global Change Research Program 271 Fourth National Climate Assessment 7 | Ecosystems, Ecosystem Services, and Biodiversity State of the Sector All life on Earth, including humans, depends on identifying measures to minimize, cope with, the services that ecosystems provide, including or respond to the negative impacts of climate food and materials, protection from extreme change is necessary to reduce biodiversity loss events, improved quality of water and air, and and to sustain ecosystem services.4 a wide range of cultural and aesthetic values. Such services are lost or compromised when This chapter focuses on the impacts of climate the ecosystems that provide them cease to change at multiple scales: the populations and function effectively. Healthy ecosystems have species of living things that form ecosystems; two primary components: the species that the properties and processes that support live within them, and the interactions among ecosystems; and the ecosystem services that species and between species and their environ- underpin human communities, economies, and ment. Biodiversity and ecosystem services are well-being. The key messages from NCA3 (Table intrinsically linked: biodiversity contributes to 7.1) have been strengthened over the last four the processes that underpin ecosystem ser- years by new research and monitoring networks. vices; biodiversity can serve as an ecosystem This chapter builds on the NCA3 findings and service in and of itself (for example, genetic specifically emphasizes how climate impacts resources for drug development); and biodi- interact with non-climate stressors to affect versity constitutes an ecosystem good that is ecosystem services. Furthermore, it describes directly valued by humans (for example, appre- new advances in climate adaptation efforts, as ciation for variety in its own right).3 Significant well as the challenges natural resource managers environmental change, such as climate change, face when seeking to sustain ecosystems or to poses risks to species, ecosystems, and the mitigate climate change (Figure 7.1). services that humans rely on. Consequently, Key Messages from Third National Climate Assessment Climate change impacts on ecosystems reduce their ability to