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Invasive Species
Overview
Invasive species, the plants and animals brought to the U.S. from other countries or relocated to new areas from within the U.S., can damage or provide competition for native plants and animals, threatening the fabric of coastal ecosystems. Invasive species can change the community structure of organisms within an area and cause substantial economic and environmental damage. Stimulated by the rapid global expansion of trade, transport, and travel, invasive species and the costs they impose on society are increasing at an alarming rate. After habitat destruction, biological invasion is considered to be the second largest cause of loss of native species and of biological diversity.
The Hawaii Coral Reef Initiative – Research Program and ECOHAB researchers are studying the impacts of invasive algae in Hawaii. The red algae Hypnea musciformis was introduced to Hawaii’s reefs in Oahu in 1974 to study its feasibility for aquaculture. When experimental trials were completed, the plantings were abandoned. Thirty years later, Hypnea has significant negative impacts on reef ecosystems. Hypnea musciformis has spread to all of the major Hawaiian Islands, except Hawaii. It forms blooms that generate new biomass of up to 9000kg/wk, much of which subsequently washes up on West Maui beaches. The large piles of decomposing biomass draw complaints from residents and drive tourists away. A recent study has confirmed significant economic impact of this nuisance species (up to $30 million/yr) in the form of lower property values and lost tourist revenue. Ten years ago, Cladophora sericea, became remarkably abundant on leeward reefs in Maui and great blooms now occur seasonally. During the blooms, large masses of the alga drift in the water column, snagging on coral and rock outcroppings and smothering out the organisms beneath. The ecologically successful green alga, Ulva fasciata, or "sea lettuce" are found in coastal waters near harbors, industrial complexes and residential areas with nutrient- rich and/or fresh water input. Blooms of Ulva fasciata coat ships’ hulls, cover pilings and shorelines, and restrict outflow pipes. U. fasciata is classified as a marine fouling organism, and studies in control and eradication are presently underway.