Invasive Species

Problems/Case Studies

"Improving on Nature?" Dennis Kingery, Metropolitan Community College. State University of New York at Buffalo's National Center for Case Study Teaching
In 1958, black bass were introduced into Lake Atitlan in the highlands of western Guatemala as a way to attract tourism and boost the local economy, but unforeseen complications resulted in an ecological disaster. Developed for an introductory course in biology, this case study first casts students in the role of the local population at that time and asks them to judge the proposal to introduce the new species of fish. The students then review the ensuing events from a historical perspective based on additional information they receive from the instructor in a progressive disclosure format.
This case is appropriate for high school and undergraduate ecology, environmental science, general biology, and aquaculture courses.

"Rabbit Calicivirus Disease: Magic Bullet or Pandora's Box? A Case Study on Biological Controls" Gary M. Fortier, Delaware Valley College. State University of New York at Buffalo's National Center for Case Study Teaching.
The characters in this dilemma case, representing the scientific community and government, must make a decision about whether or not to release a virulent pathogen into the environment in order to control the rapidly expanding population of European rabbits in New Zealand. As they work through the case, students grapple with the complex issues associated with introduced species and biological controls.
This case is appropriate for undergraduate wildlife management, ecology, and zoology courses.

"Threats to Biodiversity: A Case Study of Hawaiian Birds", Sarah K. Huber, University of Massachusetts at Amherst, and Paula P. Lemons, Duke University. State University of New York at Buffalo's National Center for Case Study Teaching
This case study analyzes the impact of introduced species on the bird populations of Hawaii. Students learn about what makes a certain introduced species more likely than another to become established in a new area; how introduced species can directly and indirectly affect endemic species; and why certain endemic species are particularly vulnerable to introduced species.
Developed for an introductory biology course, the case could also be used in in upper level courses such as ecology, conservation biology, evolution, diversity, and the biology of social issues, or in a non-majors biology course.

"Exotics". Darlene Panvini, Vanderbilt University. State University of New York at Buffalo's National Center for Case Study Teaching
This case examines the biological, ecological, social, political, and economic factors surrounding exotic species as well as the role of resource managers in shaping public policy on environmental issues.
In addition to conservation ecology courses, this case would be appropriate for a non-majors science course, a bioethics course, or a majors biology course such as ecology.

CNN Video Clips

Topic:  "Slithery Stowaways": Biology 7th Ed. CNN Ed 2003 (2:52)
Brown tree snakes now number in the millions on Guam.  DNA studies show all are descended from a single female snake that probably arrived via a ship.  The venomous snakes, which can reach ten feet in length, are an economic nuisance, a minor threat to humans, and a major disaster for Guam's wildlife.  Ten species of birds have been driven to extinction, and fruit bat populations are being decimated.  Efforts are underway to contain the snake to Guam; some snakes have already been intercepted at airports in Hawaii, Texas, and elsewhere. (Student worksheet provided on CD)

On-Line Video Clips

Kudzu - Brought to the US as an ornamental plant from Asia, Kudzu has quickly taken over much of the South despite efforts to stop it.  This video is a nice lead-in to a problem on invasive species as it shows how, without natural controls, it quickly over-grows the native flora in the Southeastern US.  


"Cuban tree frog has biologists a bit jumpy". Associated Press. The Post and Courier.  22 October 2005.
In this article, a woman from Georgia explains her sitting of the Cuban tree frog and the future effect it might have on the ecosystem.

"Invasion of Cuban tree frogs scary possibility in S.C." Petersen, Bo. The Post and Courier. 27 October 2005.
This article discusses what effect the Cuban tree frog may have on the environment in South Carolina.
"Tiny Pine Beetles Wiping Out Forests" Struck, Doug, The Washington Post. 5 March 2006.
Canadian forests are under attack by a tiny pine beetle. The range of attack is increasing and the beetle is now being seen in places that it had never been in previously. This change is probably due to the increased warmth in the climate caused by global warming. The winter is no longer severe enough to kill off the beetle.

"Further Evidence for the invasion and establishment of Pterois volitans (Teleostei:  Scopaenidae) along the Atlantic coast of the United States". Meister, H. S., Wyanski, D. M, Loefer, J. K, Ross, S. W., Quattrini, A. M, and Sulak, J. K.  Southeastern Naturalist 4:  2005. 
Further Evidence for the invasion and establishment of Pterois volitans (Teleostei:  Scopaenidae) along the Atlantic coast of the United States
The red lionfish is indigenous to the western Pacific and is an invasive marine fish. The invasion of the red lionfish into the coastal waters of South Carolina, North Carolina, Florida, and Georgia will have an impact on the local ecosystems they have invaded. 

"Australian biocontrol beats rabbits, but not rules".  Finkel, Elizabeth.  Science.  Sept 17. 1999. 
"In 1859, Thomas Austin, one of Victoria's landed gentry, introduced a few European rabbits onto his estate for sport-and Australians have been cursing him ever since.  To stop millions of foliage-eating rabbits from turning huge tracts into desert, Australia has become the only nation to successfully use a biocontrol agent on a vertebrate.  Officials released the myxomatosis virus in the 1950s, and then, as the virus's potency waned, followed it with the European calicivirus diseas (RCD) in 1995.  The new virus appears to be a stunning success:  Rabbit numbers are way down and once barren deserts are blooming.  Yet for biocontrol officials, the calicivirus experience has been a major embarrassment, a sobering lesson in the unpredictability of biocontrol agents."

"Rabbit control in New Zealand".  Duston, Trevor.  Science.  April 4, 1997.
"In view of the conflicting scientific views relating to rabbit viral hemmoragic disease (RHD) for rabbit calicivirus disease (RCD), as it is called in Australia and New Zealand, and the general lack of sound data relating to the virus (it has not been successfully grown in cell culture), the so-called "scientific testing" program conducted by the Australians for the purpose of detecting cross species transmission is highly suspect."

"What drives the 10 year cycle of snowshoe hares?".  Krebs, CJ,  Bounstra, R, Boutin, S, and Sinclair ARE.  BioScience.  January 2001. 
"The ten-year cycle of snowshoe hares, one of the most striking features of the boreal forest, is a product of the interaction between predation and food supplies, as large-scale experiments in the Yukon have demonstrated."

"Monitoring the spread of rabbit hemorrhagic disease virus as a new biological agent for control of wild european rabbits in australia".  Kovaliski, J.  Journal of Wildlife Diseases.  July 1998. 

"Release of RHD virus in Australia".  Matson, D and Smith AW.  Science.  July 5, 1996. 
"Following the escape of the mainland of the rabbit hemorrhagic disease virus (RHDV) from Wardang Island off the coast of South Australia, a monitoring program was implemented over a 13 month period, between October 1995 and October 1996 to determine the activity and rate of spread of the disease in the wild European rabbit population.  All reports of dead rabbits were investigated.... Maximum rates of spread of RGD in Australia ranged from 9km/mo during summer to 414km/mo in spring.  New cases of RHD were moderate during late autumn and winter and peaked in spring.  In summer the disease was rarely reported. "

"Rabbit Control Dilemmas".  Jarvis, B.D.  New Zealand Association of Scientisists.  March 1998. 
The report considers the evidence that the hemorrhagic disease may infect or harm non-target species. 

"Biological control not on target".  Stiling, P.  Biological Invasions 6:  151-159, 2004. 
"Non-target effects of exotic biological control agents, parasitoids and predators, released worldwide to control insect pests, are becoming more apparent.  This paper summarizes previously recorded information on the diet breadth of natural enemies released to control insect pests worldwide.  It also summarizes the diet breadth of native parasitic hymenoptera in North American to determine whether the diet breadths of native and exotic parasitoids differ.  Of released biocontrol agents, 48% were recorded as generalists  (attacking more than one genus of host) and another 29.2% attacked more than one species in a genus.  Only 22.5% were recorded as specialists on the target pests.  This suggests that many natural enemies released in biocontrol programs against insect pests have broad diets and that non-target effects are likely. "

"Have the harmful effects of introduced rats on islands been exaggerated?". Towns, DR, Atkinson, IAE, Daugherty, CH.  Biological Invasions (2006) 8:  863-891. 
"Introduced rats are now being eradicated from many islands. Increasingly, these eradications are contested by activists claiming moral, legal, cultural, historic, or scientific reasons and poorly documented evidence of effects. We reviewed the global literature on the effects of rats on island flora and fauna.  We then used New Zealand as a case study because of its four-decade history of rate eradications and many detailed and innovative studies of how rats affect native species."

"Potential impact of an exotic mammal on rocky intertidal communities of northwestern Spain".  Delibes, M, Clavero, M, Prenda, J, Blazquez, M, Ferreras, P.  Biological Invasions 6:  213-219, 2004. 
"Being the interface of sea and land, the coast can be invaded by introduced species coming from either of these two worlds.  Recent reviews of coastal invasions emphasize the human-mediated transport of non-indigenous marine plants and invertebrates, forgetting the potential role of invaders of terrestrial origin.  By studying the diet of the introduced American mink on a rocky shore of southwestern Europe, we draw attention to the potential impact on intertidal communities of exotic species coming from inland."

"Foxes, rabbits, alternative prey and rabbit calicivirus disease:  Consequences of a new biological control agent for an outbreaking species in Australia."  Pech, RP, and Hood, GM.  The Journal of Applied Ecology, Vol. 35, June 1998, 434-453. 
"The rabbit calicivirus has been introduced as a biocontrol agent for rabbits.  The consequences for fox population that use rabbits as primary prey, for populations for alternative native prey, and for pastures, were examined using a model for rabbit-and fox-prone areas of semi-arid southern Australia."

"Lessons from history:  predicting success and risks of intentional introductions for arthropod biological control."  Kimberling, DN.  Biological Invasions 6:  301-318, 2004. 
The introduction of nonnative biological control agents into a new region can cause difficulty in predicting the effect on the ecosystem.  The article discusses the US National Invasive Species Management Plan.  The author discusses the "best" way to predict success with biocontrol agents using a database.

"Increased predation on pukeko eggs after the application of rabbit control measures."  Haselmayer, J and Jamieson, IG.  New Zealand Journal of Ecology, Vol 25, 2001. 
The authors have tracked the pukeko in New Zealand.  After RHD was used to reduce the surrounding rabbit population in 1997, the authors studied the rate of predation on pukeko nests.  More nests were predated after the application of the RHD virus.  An explanation suggested is that the predation rates represent a shift in diet by the rabbit predator, the Australasian harrier. 

"Biological control of marine invasive species:  cautionary tales and land-based lessons."  Secord, D.  Biological Invasions 5:  117-131, 2003. 
The push for biocontrol in marine ecosystems has become apparent.  The author reviews 6 case studies of biocontrol in marine ecosystems. 

"Calcivirus emergence from ocean reservoirs:  zoonotic and interspecies movements."  Smith, AW, Skilling, DE, Cherry, N, Mead, JH, and Matson, DO.  Emerging Infectious Diseases Vol 4, January-March 1998. 
"Caliciviral infections in humans, among the most common causes of viral-induced vomiting and diarrhea, are caused by the Norwalk group of small round structured viruses, the Sapporo caliciviruses, and the hepatitis E agent.  Human caliciviruses have been resistant to in vitro cultivation, and direct study of their origins and reservoirs outside infected humans or water and foods (such as shellfish contaminated with human sewage) has been difficult.  Modes of transmission, other than direct oral-fecal routes, are not well understood.  In contrast, animal viruses found in ocean reservoirs, which make up a second calicivirus group, can be cultivated in vitro.  These viruses can emerge and infect terrestrial hosts, including humans.  This article reviews the history of animal caliciviruses, their eventual recognition as zoonotic agents, and their potential usefulness as a predictive model for noncultivatable human and other caliciviruses (e.g. those seen in association with rabbit hemmorhagic disease)."

"Native species vulnerability to introduced predators:  testing an inducible defense and a refuge from predation."  Whitlow, WL, Rice, NA, and Sweeney, C.  Biological Invasions 5:  23-31, 2003. 
"To manage the impact of biological invasions, it is important to determine the mechanisms responsible for the effects invasive species have on native populations.  When predation by an invader is the mechanism causing declines ina native population, protecting the native species will involve elucidating the factors that affect native vulnerability.  To examine those factors, this study measured how a native species responded to an introduced predator, and whether the native response could result in a refuge from predation."

Invasive. org
The Source for Information and Images of Invasive & Exotic Species
A joint project of The University of Georgia's Bugwood Network, USDA Forest Service and USDA APHIS PPQ.

Laboratory for Calicivirus studies
This webpage offers links to articles regarding RCD.

New Zealand Ecological Society
The New Zealand Journal of Ecology can be accessed through this site with PDF downloads of articles.

CD Resources

1.  "Invasive plants of the Eastern United States identification and control".  Bargeron, C. T., Moorhead, D. J., Douce, G. K., Reardon, R. C., and Miller, A. E.  University of Georgia Forest Health Technology Enterprise Team.  November 2003.
486 photographic images of 97 species

2.  SCDNR Aquatic Plant Management Program.  Illegal Aquatic Plants of South Carolina.  September 1997. 
Provides pictures, names, and short descriptions of these non-native plant