Biodiversity & ecosystems
Freshwater Ecosystem
The biological communities and physical environment of low-salinity inland waters — lakes, rivers, streams, springs, and wetlands — which hold a disproportionate share of Earth's species.
Definition
Freshwater ecosystems are the subset of Earth's aquatic ecosystems comprising the biological communities inhabiting freshwater bodies such as lakes, ponds, rivers, streams, springs, and wetlands, in contrast to higher-salinity marine ecosystems. They are commonly grouped into three types: lentic (still waters such as lakes and ponds), lotic (flowing waters such as rivers and streams), and wetlands (areas saturated or inundated for at least part of the year).
References
definition and water-share context
typology and fish-species share
Overview
What it means
Less than 3% of the planet's water is fresh, and most of that is locked in ice — yet freshwater ecosystems contain about 41% of the world's known fish species. They are among the most threatened ecosystem types, under pressure from abstraction, dams, pollution, invasive species, and climate change.
How it is used
The term structures conservation targets (for example inland-water targets in the Kunming-Montreal Global Biodiversity Framework), water-management planning, and the science of limnology, the study of inland waters.
Why it matters
Freshwater biodiversity is declining faster than terrestrial or marine biodiversity, and these ecosystems supply drinking water, food, flood regulation, and livelihoods for billions of people.
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