Increased warming pushing Arctic freshwater ecosystems to the brink 29 September 2019BiodiversityData and knowledgeMonitoringAssessmentsClimateRecommendationsConservation of Arctic Flora and Fauna The Conservation of Arctic Flora and Fauna (CAFF) Working Group has released the first circumpolar assessment of freshwater biodiversity across the Arctic. The State of the Arctic Freshwater Biodiversity Report, which was presented to Ministers at the Rovaniemi Ministerial meeting in May 2019, provides a synthesis of the state of knowledge about biodiversity in Arctic freshwater ecosystems (e.g., lakes, rivers, and associated wetlands). It finds that Arctic lakes and rivers are losing the ability to sustain their current level and diversity of Arctic freshwater species. Climate change and development threaten the health of Arctic freshwater ecosystems. Continued warming push cold-water species unique to the Arctic—such as the Arctic char—to the brink of regional loss, and increase the likelihood of toxic cyanobacteria blooms. These are findings from the State of the Arctic Freshwater Biodiversity Report released by the Conservation of Arctic Flora and Fauna (CAFF) Working Group at the Rovaniemi Ministerial meeting in May 2019. Freshwaters are key elements in Arctic landscapes, they provide important ecosystem services, such as drinking water, fish production, and hydropower. Yet, according to the report produced by experts from CAFF’s Circumpolar Biodiversity Monitoring Program (CBMP), warming is reducing what can be considered as Arctic. While southern species move northward, cold tolerant species face possible local extinction when they can’t adapt or compete for resources. The report provides a circumpolar synthesis of the state of knowledge about biodiversity in Arctic lakes, rivers, and associated wetlands. It identifies changes and knowledge gaps in a wide range of Arctic freshwater dwellers, from fish and benthic macroinvertebrates – small animals living on the bottom of a lake or in river beds – to zooplankton, algae, and aquatic plants. The report thus provides insights into the overall health of freshwater ecosystems and their ability to provide essential services on which people rely. For the first time, experts have compiled a circumpolar database on freshwater biodiversity to keep knowledge easily updated and available. When possible, data will be made accessible on the Arctic Biodiversity Data Service. The report also identifies Arctic countries’ efforts and gaps in monitoring key elements of Arctic ecosystems, highlighting what countries can do to improve the ability to detect and report on significant changes in the Arctic. Specifically, the report calls for better coordination, standardization of methods, increased use of emerging technologies (such as remote sensing and DNA barcoding), improved consideration of Traditional Knowledge and Local Knowledge, better engagement with local and Indigenous communities, and a commitment to support continued development and maintenance of the CBMP. During the Icelandic Chairmanship of the Arctic Council, CAFF aims at following up on the State of Arctic Freshwater Report and to continue its development of the CBMP suite of headline indicators. Key findings at a glance: Arctic freshwater ecosystems are highly threatened by climate change and human development, which can alter the distribution and abundance of species and affect biodiversity and the ecosystem services on which many Arctic peoples depend. Patterns of biodiversity vary across the Arctic, but ecoregions that have historically warmer temperatures and connection to the mainland generally have higher biodiversity than those with cold temperatures (high latitude or altitude) or on islands far from continental mainland. Temperature is the overriding and predominant driver for most key elements of the freshwater ecosystem, but climate, geographical connectivity, geology, and smaller-scale environmental parameters such as water chemistry are all important drivers of Arctic freshwater biodiversity. Available long-term monitoring records and research data indicate that freshwater biodiversity has changed over the last 200 years, with shifts in species composition being less dramatic in areas where temperatures have been more stable. Existing data are not sufficient to describe biodiversity patterns in all ecoregions, and increased sampling is required to improve understanding of biodiversity change. Better coordination and harmonized sampling, sample processing, and data storage for data from across the Arctic will improve our ability to detect and monitor changes in the ecoregion’s freshwater biodiversity. Read the full report and the key findings and advice for monitoring.