
Freshwater Species Plummet 85%: What are Our Options for Bending the Curve for Freshwater Biodiversity?
- Date: 25 October 2024
- Author: Natalie Shahbol, WWF
Freshwater ecosystems are facing a crisis. According to the 2024 Living Planet Report, freshwater species populations have dropped an alarming 85% on average—the steepest decline of any biome. Threats like habitat loss and fragmentation, pollution, and unsustainable water use are pushing rivers, lakes, and wetlands to the brink, endangering species such as river dolphins and freshwater fish. The good news is there is a global agreement to protect 30% of the planet's freshwaters, oceans, and lands by 2030, colloquially called the 30 x 30 targets.
Protecting freshwater ecosystems, however, can be challenging and calls for a range of approaches and flexible solutions. Other Effective Area-Based Conservation Measures (or OECMs) answer that call. OECMs encompass numerous conservation approaches. They include places that aren’t part of traditional protected areas but still keep wildlife populations healthy and nature functioning over time. For example, in the Mekong River Basin, community fishing areas are an important measure for maintaining fish populations crucial for both local food security and biodiversity. A newly released guidance document promotes understanding of possible types of OECMs in freshwater ecosystems that can help countries reach their 30 x 30 targets for freshwater.
Freshwater Ecosystems Need Creative and Flexible Solutions
Unlike terrestrial ecosystems, rivers and wetlands flow and connect across entire basins, such that their full extent is rarely confined within standard boundaries like a national park. For example, rivers are often part of intricate networks with numerous tributaries and vast floodplains. Rivers also flow across political and geographical borders, meaning conservation efforts in one region can be quickly undone by harmful activities upstream. Therefore, freshwater habitats need a range of solutions and approaches, like OECMs, to meet the 30 x 30 targets.
Examples of Possible OECMs
The interconnected nature of rivers means that maintaining connectivity is essential for the survival of freshwater species, which often migrate across vast areas. If upstream activities block fish passage or pollute water, it disrupts entire ecosystems downstream. By creating ecological corridors—safe zones for species to move along river systems—we can help restore this lost connectivity, which is crucial for migratory species like turtles and fish. While ecological corridors might not fit the definition of a traditional protected area, they can meet the criteria of an OECM and contribute to the 30 x 30 targets.
Another approach that doesn’t necessarily qualify as a protected area but does meet the criteria of an OECM is using “seasonal protections,” where a wetland might be temporarily restricted during key mating seasons for birds or fish, then opened again for other uses throughout the year.

The Bita River, Vichada Colombia
Case Study: The Bita River
The Bita River in Colombia showcases how inclusive conservation measures can benefit freshwater habitats. The Bita River and its associated wetlands are considered a conservation area, comparable to an OECM.
The efforts to protect the Bita River started in 2014, when the Alliance for the Protection of the Bita River was formed by government entities and citizens to collaboratively identify priorities and conservation actions for the Bita River. This collaborative approach resulted in identifying ways that the Bita River could protect nature, while allowing for economic activities that bring income and employment to the region. Therefore, fisheries and agricultural related activities continue in the Bita River; however, the Alliance became an opportunity to discuss how these activities could continue with practices that are less harmful to the river system.
The case of the Bita River is a great success story of how conservation and sustainable use could co-exist. The Bita River system encompassing a 228,000-hectare ecological corridor, enabling movement for animals like jaguars, tapirs, and river dolphins. By safeguarding migration routes and restoring connectivity, Colombia has reached its goal of protecting 30% of its lands and waters.
There are already several efforts underway to build the capacity for new conservation approaches that can follow the Bita River case. The first step is evaluating the potential for an area to be recognized as an OECM, and for that we have a site assessment tool for new OECMs.
A Path to Recovery for Freshwater Species
Flexible conservation strategies, like OECMs, offer a new pathway for garnering greater investment in freshwater biodiversity conservation. With freshwater ecosystems at a tipping point, taking immediate action and recognizing adaptable conservation measures could provide the lifeline freshwater species need to recover and thrive.