How are invasive species introduced through trade and transportation?

Invasive species are frequently introduced to new environments as unintended consequences of global international trade and transportation. These organisms, often referred to as "exotic stowaways," are transported across geographic barriers that they would not naturally cross.12

The primary mechanisms for these introductions include:

• Shipping and Ballast Water: Commercial vessels often carry ballast water to maintain stability. When this water is discharged after cargo is off-loaded, it frequently releases nonnative plants and animals into new marine or freshwater ecosystems.3
• Shipping Materials: Insects, seeds, and other organisms can hide within pallets, shipping containers, and other packing materials used in global commerce.2
• Pet and Ornamental Trade: The intentional movement of species for the pet trade or as ornamental plants often leads to their accidental or deliberate release into the wild, where they may become invasive if they possess a competitive advantage over indigenous species.12

Preventing these introductions through stricter inspections at ports and regulating the trade of exotic species is considered the most effective way to protect biodiversity.2