WILD EARTH WATCHUnderstanding Nature Through Evidence
Home / Ecosystems / Freshwater Ecosystems
Ecosystem Profile

Freshwater Ecosystems

Rivers, lakes, and wetlands cover under 1% of the planet's surface — yet freshwater wildlife populations have collapsed faster than any other biome monitored by the Living Planet Index.

Published May 2026 Last reviewed July 2026 Evidence level Strong Reading time 6 min

Overview

Freshwater ecosystems — rivers, lakes, wetlands, and floodplains — cover a small fraction of the Earth's surface but support a disproportionate share of global biodiversity, including roughly half of all known fish species. They are also, by a clear margin, the most rapidly declining biome tracked by long-term monitoring.

Established fact

WWF's 2024 Living Planet Report found an 85% average decline in monitored freshwater wildlife populations between 1970 and 2020 — steeper than the 69% decline in terrestrial populations and the 56% decline in marine populations over the same period. Migratory freshwater fish populations specifically fell 81% over the same 50 years.

Source: WWF Living Planet Report 2024; Zoological Society of London

Wildlife & Biodiversity

Freshwater habitats support an estimated one-third of all vertebrate species despite covering less than 1% of Earth's surface area, a concentration of biodiversity that makes freshwater decline disproportionately significant for overall species loss trends.

Pressures

River fragmentationDams and other barriers block migratory fish species from reaching spawning grounds; the Living Planet Report identifies river fragmentation as one of the two most common pressures on freshwater wildlife.
Water abstractionWithdrawal of water for agriculture, industry, and municipal use reduces river flows and can dry up wetlands entirely, particularly in already water-stressed regions.
PollutionAgricultural runoff, industrial discharge, and untreated wastewater degrade water quality across freshwater systems worldwide, compounding the direct habitat pressures of fragmentation and abstraction.

Regional Disparities

-95%Latin America and the Caribbean — the sharpest regional decline in monitored wildlife populations recorded in the 2024 Living Planet Index.
-76%Africa
-60%Asia-Pacific

Uncertainty & Evidence Gaps

The Living Planet Index is based on trends in monitored populations (nearly 35,000 population trends across 5,495 species) rather than a full census, and monitoring coverage is denser in well-studied regions of Europe and North America than in parts of Africa, Asia, and Latin America where declines may be under- or over-represented.