Aquatic Invasive Species Laura Fogt EEES 4730 Objective: To discuss the ecological impacts of aquatic invasive species and propose some possible solutions Definitions -Invasive species (aka exotic, non-native, alien)- species which is non-native, or alien, to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm (NISIC, 2011). -Ballast water-Water taken from a port or other location that is taken on board a ship and stored in tanks to add weight and maintain ships stability -Biotic homogenization - Occurs when non-native species become established in many places, increasing the compositional similarity among those places. -Zoogeographic pollution – Occurs when organisms are moved out of their known home range and introduced into new areas by humans. Loss of genetic integrity can occur if organisms from both habitats are closely related. -Hybridization-Interbreeding of individuals from what are believed to be genetically distinct populations, regardless of their taxonomic status (Rhymer et al, 1996) -Introgression-Gene flow between populations whose individuals hybridize, achieved when hybrids backcross to one or both parental populations (Rhymer et al, 1996) -Extirpated-Local extinction Problem-invasive species dispersed across globe through human interaction Causes -Intentional man-made pathways -Unintentional man-made pathways -Attachment of organisms to ships and boats -Canal construction -Intentional release -Shipping -Aquaculture -Ornamental fish trade Consequences -Extinctions through competitive exclusion -Threat to aquatic biodiversity conservation -Hybridization and introgression -Predation -Diseases and parasites Solutions -Strict penalties for violations -Ballast-water exchange -Follow guidelines set forth by experts Research paper-“Impacts of alien invasive species on freshwater fauna at risk in Canada” -Alan Dextrase and Nicholas Mandrak, 2003 -Study examines threat factors contributing to the endangerment of freshwater fishes and molluscs in Canada and the nature of alien invasive species introductions affecting aquatic species at risk -Status designations of extinct, extirpated, endangered, threatened and special concern assigned by the Committee on the Status of Species at Risk in Canada (COSEWIC) -Found that alien invasive species was second only to habitat loss as a threat factor for at risk fish species -Alien invasive species primary threat factor for about half of mollusc species, all due to impact of zebra mussels -Seven pathways determined for invasive species: sport fishing, ballast discharge, aquarium fish release, canals, movement of recreational boats, aquaculture and horticulture escapes References Anonymous. 2011. What is an invasive species? Referenced from http://www.invasivespeciesinfo.gov/whatis.shtml. Accessed on October 29, 2011. Dextrase, A. and N. Mandrak. 2004. Impacts of alien invasive species on freshwater fauna at risk in canada. Biological invasions. 8: 13-24 Rhymer, J. and Simberloff, D. 1996. Extinction by hybridization and introgression. Ecology, evolution, and systematics. 27: 83-109. Referenced from http://www.annualreviews.org/doi/pdf/10.1146/annurev.ecolsys.27.1.83. Accessed on October 29, 2011.