The IUCN Red List of Threatened Species recently conducted the most extensive global assessment into the status of freshwater species which produced numerous findings into the status of these species, the threats they face, and the potential for conservation solutions. Significantly, the study published in Nature found that 24% of the world’s freshwater fish, dragonfly, damselfly, crab, crayfish, and shrimp species are at high risk of extinction. On the impact of the assessment, Catherine Sayer, IUCN Freshwater Biodiversity Lead and lead author to the paper, said, ‘Lack of data on freshwater biodiversity can no longer be used as an excuse for inaction. Freshwater landscapes are home to 10% of all known species on Earth and key for billions of people’s safe drinking water, livelihoods, flood control, and climate change mitigation, and must be protected for nature and people alike…This information will enable policy makers and actors on the ground to plan freshwater conservation measures where they are needed most.’
IUCN Red List Graphic from the findings of ‘One-quarter of freshwater fauna threatened with extinction.’ Made in collaboration with Conservation International.
Hump-backed Mahseer (Tor remadevii) has been listed as Critically Endangered by IUCN’s Red List with a decreasing population trend. Researcher Adrian Pinder of Bournemouth University stands with a Hump-backed Mahseer. [Bournemouth University]
While freshwaters are vital for ecological and social wellbeing, they only cover 1% of the Earth. Freshwater landscapes include natural inland wetlands, forests, and free-flowing rivers – all of which face high levels of threat from human activity. The interconnected nature of terrestrial and aquatic realms in freshwater conservation from forests to rivers and wetlands has been little acknowledged implemented at the international level (often land and sea are separated in conversation) although collaboration between the two ecosystems is of extreme importance for these freshwater species. This creates unique threats and conservation solutions for freshwater species to that of other flora and fauna with which they share habitat. For example, Dr Rajeev Raghavan, South Asia Chair of the IUCN SSC Freshwater Fish Specialist Group and paper co-author, explains ‘Although they live side by side in the Western Ghats, conservation action for tigers and elephants will not help the Critically Endangered humpbacked mahseer (Tor remadevii), which is threatened by habitat loss due to river engineering projects and sand and boulder mining, poaching and invasive alien species. Active protection of the river and tributaries where the humpbacked mahseer lives is essential to its survival, in addition to fishing regulations and banning the introduction of further invasive alien species.’ This framing is crucial to ensure conservation action is targeted to protect those species at high risk of extinction.
What did the assessment find?
In addition to the conclusion that a quarter of freshwater species are at risk of extinction, the study also determined risks to conservation of these fauna. According to the study’s findings, over half of freshwater species are threatened by pollution. Other significant threats found include dams and water extraction, land-use change and associated effects from agriculture, and invasive species and disease. Most threatened freshwater species are affected by more than one threat. The authors note that each species experiences a diversity of threats, making detailed assessment and resulting comprehensive conservation steps necessary for protection. Importantly, the study discovered that high water stress (high demand and low supply) and eutrophication (excess nutrients in water) are not necessarily indicators of higher numbers of threatened species being in an area. “This shows that water stress and eutrophication are not good indicators for locating threatened species and should not be used to guide conservation. Instead, it is essential that freshwater species data are actively included in conservation strategies and water use planning and management, to ensure their practices support healthy freshwater ecosystems,” said Dr Topiltzin Contreras MacBeath, Co-Chair of the IUCN SSC Freshwater Conservation Committee. “Increased investment in measuring and monitoring freshwater species is needed to ensure conservation action and water use planning is based on the latest information.”
Spatial spread of threatened species also marked an important part of the study. The richest abundance of freshwater species was found to be in the tropics. The study found Lake Victoria, Lake Titicaca, Sri Lanka’s Wet Zone and Western Ghats, in particular, to have the greatest richness of freshwater species.
‘Fig 3: Absolute richness of freshwater species’ from ‘One-quarter of freshwater fauna threatened with extinction.’
So what do we do now?
“These landmark findings are a rallying cry around freshwater species and the declining habitats that support them. Historically, the important role of freshwaters in safeguarding global biodiversity has been overlooked, and key differences in how these systems should be managed are only now being recognised. It is imperative that conservation actors work collaboratively to address the challenges of pollution, shortsighted habitat modification, and the spread of invasive species head on. The solutions to these threats may be novel and innovative, and the data presented here can be used as a roadmap to guide our collective efforts,” said Tim Lyons, Director of Conservation at New Mexico BioPark Society.
We now know that one-quarter of freshwater species are threatened. As we look ahead to a packed year of environmental work, including the upcoming World Conservation Congress, we have the tools; let’s make the change.
