SPECIES INVASIONS: Water Hyacinth and Zebra Mussels
Intern at No Water No Life
Water hyacinth (Eichhornia crassipes) is a perennial, free-floating aquatic weed, native to South America’s Amazon River, but carried overseas for ornamental use. Today the water hyacinth is considered to be the “world’s worst aquatic weed.” This aggressive, invasive species spreads rapidly over entire surfaces of lakes and ponds and can double its coverage in just two weeks. Yet its ability to withstand drastic fluctuations in flow rates, acidity and low nutrient levels makes it a viable and popular water-garden plant.
Since imported to North America in 1884, it has invaded the Columbia and Mississippi River Basins, two NWNL case-study watersheds. Also introduced into East Africa, it is present in three NWNL basins: those of the Omo, Nile and Mara Rivers. Recorded in Egypt as early as the 1890’s, water hyacinth became a “plague” in the late 1900’s. River control schemes, such as dams, barrages and irrigation canals have encouraged its growth and spread. Furthermore, climate change, a combination of higher temperatures and CO₂ fertilization, is significantly increasing water hyacinth proliferation. Read more.