Invasive species are non-native to a particular region, and negatively impact native species through interactions such as predation and competition.
- In many cases, invasive species become dominant and cause significant declines or extinctions of native species. Invasive species have been identified as one of the most significant threats to biodiversity globally. Losses of native species are associated with changes in food webs and ecosystem functions, such as the cycling of nutrients through ecosystems.
- Species can expand their ranges naturally, but the rate and distance of range expansion of many invasive species can only be explained by human intervention. Humans transport invasive species in ballast water, through long-distance trade of plants and animals for aquarium, horticultural, or agricultural use, and through recreational activities such as boating.
- Invasive species negatively impact many commercial and recreational activities in the ocean, having significant costs to humans. For example, populations of many important fishery species have declined as a result of invasive species introductions.