Exotic+and+Invasive+Species+Project+expected+answers

Expected team answers for general content (26):

 * **What is a non-native species?**
 * A non-native species is any species that has been removed from its native habitat and transplanted to an environment in a new geographic area. While less than 1% of those arriving in new environments become established in their new location, this small percentage has a disproportionate damaging effect on native biodiversity.


 * **What is an invasive species?**
 * An invasive species is a non-native species that has become establihed in a new environment, is or is likely to cause ecological, economic or human health problems. Invasive species cause harm by preying upon, parasitizing, outcompeting, or introducing disease in native species.


 * **How have people and their activities caused non-native species to spread to new environments?**
 * Some non-native species like purple loosestrife (//Lythrum salicaria//) and kudzu (//Pueraria lobata//) were intentionally introduced to new enviroments in the United States, while other species were introduced accidentally in ships' ballast water like the zebra mussel (//Dreissena polymorpha//). Others escaped captivity like bighead carp (//Hypopthalmichthys nobilis//) and silver carp (//Hypopthalmichthys molitrix)//, and the African honeybee (//Apis mellifera scutellata// Lepeletier). They have also been transported unknowingly on boats and trailers, clothing, footwear, produce, and animals.


 * **What are some of the different ways that invasive species affect our environment?**
 * Invasive species destroy biodiversity, damage economic interests related to displaced species, introducing or spreading new diseases that they carry. When exotic species become invasive, they may diminish the value of natural resources like agricultural crops, livestock, forests, and other managed resources.


 * **What are scientists doing to control invasive species?**
 * Scientists are attempting to control invasive species with physical barriers, quarantines, pheremone fences, and sophisticated monitoring like environmental DNA sampling.


 * What things can individuals do to limit the spread of invasive species?
 * Individuals can avoid transporting firewood, animals, fruit and produce across national borders, clean shoes and clothing before entering and leaving natural environments while hiking or camping. Many groups also recruit and train volunteers to monitor exotic and invasive plant species, report sightings, and respond with appropriate oversight to control estblished infestations.


 * **How does the problem of invasive species compare to other environmental problems?**
 * Invasive species are second only to loss of habitat as a threat to biodiversity. Recently, the total cost of invasive species to the US economy was estimated at $137 billion. The damage done by invasive species is more durable in nature than the effects of habitat degradation, fragmentation and pollution, which can be reversed in years. Once invasive species are established, they may be impossible to remove from communities.

Expected individual answers for the 6 pairs of exotic species (26):

 * **Cheatgrass**
 * Cheatgrass has become a problem because it grows densely and outcompetes many native grasses and shrubs including the ecologically important sagebrush. During dry portions of the spring and summer, the dry cheatgrass is highly flammable, and creates a wildfire danger.


 * **Indian mongoose**
 * The attempt to introduce the Indian mongoose to control rats in sugar cane plantations was one of the worst attempt as biological control ever made. The mongoose decimated many species of native birds, and did very little to control the growing rat population.


 * **European Green Crab**
 * The European Green Crab has become one of the most invasive predators in marine and estuary ecosystems. It has caused many economically valuable native species to decline dramatically. Examples include the North Amermican scallop populations, and New England soft-shell clam fisheries, which have declined due to predation by the European green crab.


 * **Eucalyptus Tree**
 * After it was discovered that the tree was a poor source of lumber, and the demand for firewood declined after the Great Depression, there was little commercial use for the Eucalyptus tree. Unfortunately, by then the species was spreading rapidly and outcompeting local California hardwood trees. Native oak woodlands support over 100 times more species than virtual monocultured eucalyptus tree stands.


 * **Asian Swamp Eel**
 * The Asian swamp eel is a predatory fish with no predators after being introduced in North America. They are currently disrupting existing food webs by competing with native fish and wading birds for prey.


 * **Asian Long Horned beetle**
 * Wiped out many shade and landscape hardwood trees such as elm, maple, birch, ash, horsechestnut and poplar. The Asian long horned beetle has the potential to disrupt numerous forest and urban ecosystems as it spreads, and becomes established through much of the United States.