Grand Challenges to Support the Freshwater Biodiversity Emergency Recovery Plan

Abstract

The year 2021 offers a critical opportunity for concerted action to influence the future of freshwater biodiversity, ecosystem services and human well-being. The United Nations Decade on Biodiversity 2011–2020 has ended, and governments around the world are reviewing major international agreements relevant to biodiversity conservation, including the Convention on Biological Diversity (CBD)¹, the Sustainable Development Goals (SDGs)², and the UN Framework Convention on Climate Change (UNFCCC)³. A Post-2020 Global Biodiversity Framework⁴ is under development, with the grand mission to “Halt the loss of species, ecosystems and genetic diversity by 2030; restore and recover biodiversity to ensure a world of people “living in harmony with nature' by 2050”. Freshwater ecologists have acted quickly to draw attention to the global dimensions of the freshwater biodiversity crisis and address the lack of a comprehensive framework to guide policy responses (Bunn, 2016; Darwall et al., 2018). An Emergency Recovery Plan for freshwater biodiversity, published by 25 authors from 14 organizations (Tickner et al., 2020), sets out six major priorities for global action and policy development to “bend the curve of freshwater biodiversity loss.” It has been submitted to the working committees of the Post-2020 Global Biodiversity Framework, and further promoted as a dramatic OUPblog “Bring living waters back to our planet⁵” Comprehensive reviews have since enumerated many research questions, actions and policy refinements needed to “bend the curve” and protect the world's freshwater ecosystems (van Rees et al., 2020; Buxton et al., 2021; Harper et al., 2021; Maasri et al., 2021). Each review cuts across important scientific, societal, management and policy issues. The purpose of this brief challenge paper is, likewise, to strengthen and support the Emergency Recovery Plan, but in a different way, by advocating a broader package of strategic activities that too often operate in silos, with patchy coverage of the world's freshwater ecosystem types and biogeographic diversity. This package presents traditional areas of scientific and societal activity that require more strategic, integrated and collaborative global effort to deliver evidence-based freshwater conservation outcomes, conjoined with terrestrial and estuarine/marine conservation, depending on context: (i) inventory, evaluation and research; (ii) restoration and rehabilitation; (iii) protected area design and management; and (iv) socio-ecological science and governance. The paper is intended to motivate greater interest, commitment and collaboration of all stakeholders in the most urgent and ambitious conservation enterprise of the next decade—to protect and sustain freshwater biodiversity in the socio-ecological systems of the Anthropocene. Evidence-based ecosystem restoration and biodiversity protection depend upon a credible foundation of scientific and sociological data, process understanding and a capacity to model, predict and evaluate ecological/societal outcomes from natural processes, pressures and management actions. Notwithstanding a huge body of erudite freshwater research, there remains an ongoing need to increase understanding of the biodiversity, biophysical processes and ecosystem services of the world's freshwater and connected terrestrial and estuarine/marine ecosystems. The IUCN Commission on Ecosystem Management has developed a globally consistent, spatially explicit Ecosystem Typology for conservation purposes (Keith et al., 2021). It is designed to help identify the ecosystems most critical to conservation of biodiversity and supply of ecosystem services, as well as structuring global risk assessments for the Red List of Ecosystems and reporting against CBD and SDG targets and other framings. The typology distinguishes 28 natural freshwater ecosystem types within subterranean systems, palustrine wetlands, streams, rivers, freshwater and saline lakes, artesian springs, oases, and transitional waters (fjords, estuaries, intermittently closed and open lakes and lagoons–ICOLLS). Depending on ecosystem type, geography and knowledge gaps, freshwater inventory and research is traditionally integrated around taxonomy, genetics and organismal biology, population and community ecology, and ecosystem functions, the latter including the processes that link landscapes, connected boundary systems (riparian areas, floodplains, wetlands/lakes, and groundwater systems) and freshwater ecosystems (Geist, 2011; Reis et al., 2017; Flitcroft et al., 2019). Likewise, the pathways and processes that connect rivers and estuaries via surface flows and submarine groundwater discharges are vital dimensions of interconnected freshwater and coastal ecosystems. The IUCN Ecosystem Typology provides a geographic framing and scientific resource to help guide priorities for basic inventory and ecological research on understudied ecosystem types and biogeographic regions. For example, groundwater-dependent ecosystems such as artesian springs and oases are relatively poorly studied but coming to attention globally (Cantonati et al., 2020). Intermittent rivers and ephemeral streams (IRES) and episodic arid-zone floodplains are of growing interest because even when dry they perform multiple ecosystem services that complement those of nearby perennial rivers (Datry et al., 2018). Given the exceptional biodiversity of the Amazon...