Invasive species are defined as non-native organisms that establish themselves in a new environment and cause measurable harm to ecosystems, economies, or human health. Their impact on water quality is one of the most serious and least understood consequences of biological invasion. Invasive species cost the US economy over $12 billion annually in environmental and economic damages, with $5.4 billion attributed to non-native freshwater fishes alone. That figure reflects only direct costs. The wider damage to drinking water, fisheries, and recreational water bodies adds considerably more. Understanding these mechanisms is the first step towards protecting the freshwater systems that communities depend on.
How do invasive species alter aquatic ecosystems to degrade water quality?
Invasive species degrade water quality by dismantling the ecological processes that keep freshwater systems clean and functional. The damage is not always visible at the surface, but it accumulates rapidly once an invader establishes itself.