Benefit and harm

Intentional introductions of alien species and populations occur in many branches of commerce and have resulted in large economic profits for humans. trees are introduced for forestry, crops and vegetables are introduced for agriculture, parks and roadsides are sown with seeds from alien species, alien fish and molluscs are introduced for aquaculture and fisheries. Alien viruses, insects and microorganisms are used for biological control and sanitation of soil and have lead the use of more environmentally sound and cost effective methods. The reverse side of the picture is damage to the biological diversity and economic costs to combat and control alien species that have caused problems for the ecosystem or for economically important branches of commerce.

• Agriculture
• Parks and gardens
• Pets
• Wildlife
• Aquaculture and stocking of fish and crustaceans
• Transport