Invasive Species
Invasive Species Wiki

Often plant and animal extinctions occur because other species have been deliberately or accidently introduced to the ecosystem and take resources from the native species. Introduced species to the US include corn, wheat, rice and animal species including cattle and poultry. These introduced species account for more than 98% of the US food supply. However, some introduced species do not have natural predators, competition or other means to control their numbers and then begin to crowd out other species.

For this assignment you will identify one invasive species, describe how it was introduced and describe the ecological and economic harm.


Picture(s) of species 5 pts
Description (characteristic, habitat, needed resources) 5 pts
Ecological impact 5 pts
Economic impact 5 pts

Due Tuesday, December 6, 2011

Kudzu- Carleton Gibson
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Kudzu is a vine that is originally from southeast Asia in China, Japan, and Korea. There are tons of leaves attatched to the vine. These leaves are unique in the fact that they have to ability to fix atmospheric nitrogen. Also attatched to the vine is little stems called nodes. These nodes allow Kudzu to grab onto walls, buildings, and other surfaces to grow upwards. The Kudzu reproduces by its ability to "root" whenever it is in the presense of soil which allows the plant to keep expanding. The plant prefers subtropical climates with high temperatures and high exposure to. The plant was first introduced to the US intentionally when it was brought to an exposition to celebrate the 100 year anniversary in 1876. After that, the plant become very popular amongst the American public as an ornament plant to decorate homes in the Southeastern USA. The plant became very highly used by farmers as a method to feed cattle. However, many farmers had to relocate in the mid 1900s which meant that their previous farms were abandoned and therefore the kudzu vine was unattented to. The vine continues to grow exponentially in the SE USA and now covers over 3 million hectares of land. Kudzu has a very dangerous ecological impact because it can smother other plants and trees and kill them. Its growth is very hard to stop because of its ability to produce its own nitrogen and therefore cannot really be contained except for cutting it down. Even cutting it down does not do much because it grows roughly a foot per day. Also, each individual vine has an extreme amount of roots and every single stem must be eliminated in order for the plant to be removed successfully. In addition to flat out smothering plants. Kudzu blocks the sunlight from reaching plants that grow beneath it and can kill them that way. Along with ecological impacts, Kudzu has a far reaching economic effect. An estimated 100-150 million dollars of expected forest productivity is lost because of the overgrowth of Kudzu. Kudzu damages power lines constantly in the south by causing them to collapse which costs power companies roughly 1.5 million dollars per year to control. Kudzu damaged buildings and historic sites and therefore it costs about $5,000 per hectare per year to control the growth.

Sam Scarpino- Zebra Mussels

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Zebra mussels live in D-shaped shells with stripes that travel down them. Zebra mussels tend to form colonies in large numbers, especially in areas where there are very few natural predators. They are native to the Black Sea and the Caspian Sea but were brought from those areas by trade to North America, Great Britain, Ireland, Italy, and Sweden. While there, because they have no natural predators due to their being an invasive species, they have caused many problems both ecologically and economically. Ecologically, the zebra mussel has caused a decrease in other kinds of mussels. This is because since they have no natural predator, they to form colonies of many members almost anywhere. Because they have little to fear with regards to predation, they are able to use up resources that other mussels need, causing other organisms to be nearly extinct. However, smallmouth bass and yellow perch seem to be rising in numbers as a result of the zebra mussels’ invasion. Economically, the zebra mussels have posed a very serious problem to fishermen especially in the Great Lakes. It is estimated by the Center for Invasive Species Research at the University of California, Riverside that the annual cost for maintenance due to the negative effects of the zebra mussel is $500 million. This cost is due to zebra mussels making colonies in almost any place. Undersides of bridges and boats can be covered with hundreds of them. In addition, pipes can become effectively clogged due to their colonization. This causes problems for both hydroelectric companies as well as municipal water supplies. The removal of the mussels from pipes is very time-consuming and costly. Because of this, they have been placed as a target in the United States Invasive Species Act.

Emily Schmitt--Yellow Starthistle

The yellow star thistle is native to Eurasia that had entered the U.S in the late 1800’s. Yellow star thistle is a gray-green to blue-green plant with a deep, vigorous taproot. It produces bright, thistle like yellow flowers with sharp spines surrounding the base. Yellow star thistle grows to heights varying from 6 inches to 5 feet. The stems of mature plants are rigid, spreading, and typically branching from the base in open areas. Stems and leaves are covered with loose, cottony wool that gives them a whitish appearance. This plant came to the U.S through accidental seed contamination. It is now common in open areas on roadsides, rangeland, wild lands, hay fields, pastures, and waste areas. Recent reports indicate that yellow star thistle infests between 10 and 15 million acres in California. Disturbances created by cultivation, poorly timed mowing, road building and maintenance, or overgrazing favors this rapid colonizer. It forms dense infestations and rapidly depletes soil moisture, thus preventing the establishment of other species. It is also poisonous to horses, causing a nervous disorder called “chewing disease”, which is fatal once symptoms develop. Horses are the only animal known to be affected in this manner.
Burmese Python-Troy Baltutat

Purple loosestrife - Danielle vonWaldow


The purple loosestrife is a highly aggressive plant invader of wetlands that can produce up to 2.7 million seeds per plant yearly, and spreads across approximately 480,000 additional hectares of wetlands each year. The plant of European origin, has spread and degraded temperate North American wetlands since the early nineteenth century. The plant was introduced both as a contaminant of European ship ballast and as medicinal herb for treatment of diarrhea, dysentery, bleeding, wounds, ulcers and sores. The purple loosestrife is a herbaceous, wetland perennial that grows in a wide range of habitats. Established plants can reach heights of 2m with 30-50 stems forming wide-topped crowns that dominate the herbaceous canopy. One mature plant can produce more than 2 million seeds annually. Seeds are easily dispersed by water and in mud adhered to aquatic wildlife, livestock and people. High temperatures (>20°C) and open, moist soils are required for successful germination and seedling densities can approach 10,000-20,000 plants/m2. A woody rootstock serves as a storage organ, providing resources for growth in spring and regrowth if the above-ground shoots are cut or damaged. Invasion of this plant into a wetland can result in the suppression of the resident plant community and the eventual alteration of the wetland's structure and function. Large monotypic stands of the plant jeopardize various threatened and endangered native wetland plants and wildlife by eliminating natural foods and cover. Dense plant establishments in irrigation systems has impeded the flow of water. No effective method is available to control the plant, except where it occurs in small localized stands and can be intensively managed. In such isolated areas, uprooting the plant by hand and ensuring the removal of all vegetative parts can eliminate it. Other control techniques include water-level manipulation, mowing or cutting, burning, and herbicide application. These control methods are costly, require continued long-term maintenance and, in the case of herbicides, are non-selective and environmentally degrading.

Burmese Python-Troy Baltutat

The importation and keeping of Burmese Pythons in Florida has led to some rather serious problems. People who no longer wish to care for their pythons, or whose pythons have grown too large to be kept in their houses, have been known to release their pets into the wild rather than have them re-homed or even humanely euthanized. This has been particularly problematic in South Florida along with possible zoo, warehouse, and household escapees from Hurricane Andrew where a large number of pythons have made their way to the Everglades They have thrived there, begun to reproduce prolifically, and become an invasive species. Over 1330 (US Natural Park Service website - Dec 31 2009) have been captured in the Everglades. Since they have been known to eat endangered birds and alligators, these snakes present a new danger to an already fragile ecosystem. Environmentally, these animals are taking over the habitat and decreasing their prey populations. Economically, it costs roughly millions of dollars to hunt and extract these pythons and put them in safe habitats. There are several tv shows which detail this process, but invasive species such as this one cause a huge disturbance in the economy. Taxpayers money is going to the aid and rescue of these python species.In February 2008, USGS scientists published a projected range map for the US, based on average climate data of the snake's home range and global warming projections, which predicted that these snakes could eventually migrate to and flourish in as much as a third of the United States by the end of the 21st century. However, a subsequent study produced a map incorporating both climatic extremes and averages, which showed the Burmese python's range to be limited to Southern Florida.

Water Caltrop (Water chestnut) Kristen Walczak
The Water Caltrop is a rooted aquatic plant with a leafy rosette that floats on the surface. Stems reach up to 16 feet, with two types of leaves. Submersed leaves are feathery, whorled along the stem and up to 6 inches long. The leaves are triangular, 1 to 2 inches long, waxy and have toothed edges.
The flowers are small, white, have 4 petals and bloom from mid-July to fall frost. The fruit is a one-inch wide woody nut armed with 4 stout barbs. The Water Caltrop was originally from Eurasia, and is now found in parts of the northeastern states.

The Water caltrop was released into waters of the Northeast in the late 1800s, and is now inexorably,spreading throughout New York State, clogging waterways and ponds and altering aquatic habitats.

Each rosette can produce 15 nuts per season which sink to the bottom and remain viable for up to 12 years. The seeds germinate in spring and each new plant can divide into 10 - 15 rosettes over the summer. One acre of water chestnut can produce enough seeds to cover 100 acres the following year.
Water chestnut has become a significant nuisance, particularly in the Hudson, Connecticut and Potomac Rivers, and in Lake Champlain. The plant can form nearly impenetrable floating mats of vegetation. These mats tend to create a hazard for boaters and other people on the water. The density of the mats can severely reduce or eliminate the growth of native aquatic plants beneath the canopy, and therefore eliminates native fish as well. This creates the economic problem for fishermen who need those fish in order to make a profit. Small populations of water chestnut, found in the early stages of colonization, can be controlled by simply hand pulling them out. But, large infestations usually require the use of mechanical harvesters or the application of aquatic herbicides. Today, research is underway at Cornell University to find biocontrol insects from Trapa’s native China, where such predators help keep the plant in check.

Silver (Asian) Carp--Anna Siegfried
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The silver carp is a filter feeding fish that was imported from China in the 1970’s. The Mississippi River and its tributaries downstream are the most common places to find silver carp. They have low-set eyes that are below their mouths, and their mouths are largely upturned without barbells (whisker-like feelers). There are no scales on their heads, and their body scales are very small. Silver carp weigh up to 60 pounds. They often feed in schools near the water’s surface. When the water is disturbed by boats the silver carp are known to jump out of the water; these fish can jump up to 10 feet. Oftentimes the fish will jump into passing boats and injure the passengers; some water skiers even have been injured from jumping silver carp. They live in temperate freshwater in both their native and introduced habitats. These fish also favor large rivers and connecting lakes. Silver carp must migrate upstream to lay their eggs which then float downstream to floodplain zones. Because they reproduce prolifically, their population grows quickly, and they spread very fast. The silver carp was imported to control plankton and algae in aquaculture ponds, but around the 1980’s, this carp escaped into open waters. Silver carp are gluttonous eaters; they can eat huge amounts of plankton and detritus. Since these fish eat plankton, there is more competition for native filter feeders such as mussels and paddlefish. This higher demand limits resources disrupting the entire food web in a body of water. If introduced, scientists fear silver carp will dominate the Great Lakes. Currently, the Chicago Sanitary and Ship Canal built an electric barrier system to stop silver carp from reaching Lake Michigan. Although, flooding on the Des Plaines River could carry carp overland past the barrier. Two other barriers on the Mississippi River have been recommended, but the system will have to be more technologically advanced because of the native fish that need to travel up downstream. This required advancement will be extremely expensive. Also, reduced abundance of native fishes results in reduced harvest by commercial and sport fishers. The abandonment of most commercial fisheries along the Mississippi River due to Asian carp domination was recently reported. The economic impact cost of the Great Lakes’ commercial, tribal, and sport fisheries is estimated to be over $7 billion annually if the carp are introduced there.

Japanese Stiltgrass---Vinay Viswanathan
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Japanese Stiltgrass (microstegium vimineum), is an grass originating in East Asia (Particularly Japan, the Korean peninsula, and China). The Japanese Stiltgrass is usually green, often with a silver stripe going through the leaf, and is considered by many to be a noxious weed. They can grow up to 3 feet (approximately 90 cm) with most plants ranging from 1 foot to 2 feet tall. They bloom white flowers in late-summer. Though the plants die each fall, they are annual therefore they normally grow back the following year. They have a very wide ecological niche and can flourish in surroundings ranging from grassy plains to forests to swampy wetlands. Their wide niche is a major reason for them being highly invasive. It prefers shade but also grows in full sunlight. And, while they do grow in a wide array of conditions, they prefer moist, moderately acidic soils which are high in nitrogen. They have high reproductive rates and their seeds mature in the fall. Seeds often move via rain waters or may be contaminated in soil or by human equipment (like shoes). They now are harming much of the Ohio River Valley, ranging from Western Pennsylvania to Indiana, Illinois, and the Midwest as well as the Upland South like Kentucky and West Virginia. Still, they are endemic to other states ranging from Georgia to Delaware to New York. The ecological impact of the Japanese Stiltgrass is quite severe; they mainly invade regions in patches and force out less competitive species. Their invasiveness is exacerbated in the presence of white-tailed deer, who are wont to avoiding the Stiltgrass and instead feeding on other grasses, therefore increasing the percentage of the community that is composed of microstegium vimineum. They also hurt other plants by changing soil chemistry and placing excessive shade over the soil. The result of this is that often times Japanese Stiltgrass act as weeds and harm other plants. Economically, this can wreak havoc because farmers may have plants with short stems which die off because they lose resources and have a transformed habitat due to the presence of much Japanese Stiltgrass.

Brown Tree Snake- Anna Meenen

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The brown tree snake is an arboreal rear-fanged colubrid snake native to eastern and northern coastal Australia, Papua New Guinea, and a large number of islands in northwestern Melanesia. They typically reside in forested lands as well as grasslands. This snake is infamous for being an invasive species responsible for devastating the majority of the native bird population in Guam. The brown tree snake preys upon birds, lizards, bats and small rodents in its native range. Due to the availability of prey and lack of predators in introduced habitats such as Guam, they have been known to grow to larger sizes than their normal 1 to 2 metres (3.3 to 6.6 feet) in length. The longest recorded length of this species is one found on Guam measuring three meters. The female is known to produce 4-12 oblong eggs, 42-47 mm (1⅝-1⅞ in.) long and 18-22 mm (⅝-⅞ in.) wide with leathery shells. The female deposits the eggs in hollow logs, rock crevices, and other sites where they are likely protected from drying and high temperatures. The brown tree snake is a nocturnal snake that can be very aggressive when confronted. It has two small, grooved fangs at the rear of the mouth that can release venom. After WW2, the brown tree snake was accidentally shipped from the South Pacific to Guam. Because of the lack of natural predators outside of feral pigs, as well as a ton of prey, the brown tree snake's population rose to unprecedented numbers. Ecologically, the snake has caused despread loss of domestic birds and pets. They have also caused considerable emotional trauma to residents and visitors alike when snakes invaded human habitats with the potential for envenomation of small children. Economically, the snakes have caused the extirpation of most of the native forest vertebrate species and thousands of power outages affecting private, commercial, and military activities. This goes to show that not only do invasive species affect animals, but humans as well, for all life is truly interconnected.

Jenny Godwin- Stink BugBrown_marmorated_stink_bug_adult.jpg

The Stink bug is native to Asia, and it is currently causing nationwide economic damage. The brown marmorated stink bug was accidentally brought to America in the late 90's- the exact reason for its introduction is not known, however; it is believed that it 'caught a ride' in some shipping crates. Althought the first documented stink bug was caught in Allentown, Pa, it quickly spread thoughout the eastern states and it is now documented in 34 states total. The adult stink bug is approximately 1.7 centimetres (0.67 in) long and just about as wide, forming the "shield" shape characteristic of other stink bugs. They are various shades of brown on both the top and undersides, with gray, off-white, black, copper, and blueish markings. The stink glands are located on the underside of the thorax, between the first and second pair of legs, and on the dorsal surface of the abdomen. Stink bugs do not survive in cold temperatures, so they enter and other structures in the late summer- typically September. They live in these structures until June, when their natural food supply is available again. In the wild it eats a wide range of fruits, vegetables, and other host plants including peaches, apples, green beans, soybeans, cherry, raspberries, and pears. Because they will eat almost anything, they are causing nationwide economic damage to crops. It was estimated that in 2010 they caused $37 million of damage just to apple crops alone. This results in food shortages of certain crops, and farmers are losing a great deal of money (without crops they don't have an income). The ecological impact of stink bugs is also bad. They are not just destroying farms, but also endangered species of plants. They are basically destroying all types of plants, and there is no known predator of them. In Asia, they do have one predator, but this insect is not present in America. A certain species of wasp may be able to kill the stinkbug, so researchers are looking into that.

Giant Reed-Hannah Wilhelm


The Giant Reed is a tall (can grow up to 20 ft. high) perennial grass with foot long leaves. In the summer months, the Giant Reed blooms flowers with silky long hairs. It was originally found in India/ southern Asia but is now located in almost all U.S. states, most abundant in the coastal states. In order to grow, all this species needs is semi-drained soil where moisture can always be present. Because of these characteristics, the Giant Reed can grow in a variety of soil, including soil with high levels of salinity. It was planted in Florida, California, and the Carolinas for erosion control. Unknowingly, the plant spread like wildfire and began using all resources and leaving none for native plant species. It was also planted in wastewater treatment facilities as a filter plant. A lot of places have stopped using this filter plant because it reproduces very quickly. This species grows clumped together, forming a wall-like structure with a thick, impenetrable root system. Because of this growth, animal species, especially birds and amphibians, cannot form nests/habitats along the marshes anymore. Economically, the species uses up a lot of water, about 52,600 feet-acres of water a year in the Santa Ana River Basin. This amount is enough to serve a population of about 130,000 people a year; instead, the water being taken away costs the Santa Ana River Basin population of humans about $12 million in transportation of water from other areas. Some methods, such as cutting, burning, and using pesticides have been used to help decrease the size and spread of the species, but these actions will not eliminate the species completely since they are only completed in moderation.

European Starling - Chris Beaulieu
The European Starling is small bird no bigger than 10 inches long and weighs around 3 ounces. In the summer, adult starlings are grey or brown with black speckles on their glossy looking wings. During the winter they're feathers look less glossy and more ruffled and they develop white spots on their wings. They have a short tail and are general stocky with a hump back. Starlings are now one of the most common songbirds present in North America. Starlings are known for their habit to travel in large flocks and for their occasional over-aggressiveness. The Starling was first introduced in New York in 1890 by an individual who felt the need to provide America with every bird ever mentioned in one of Shakespeare's works. Since then the population started to grow and spread across the whole Continent. The European Starling was soon spotted in Nebraska in 1930 and in California in 1942. It is estimated that current starling population in America is somewhere around 140 million. Starlings will nest almost anywhere there is a hole or small cavity and that makes them very versatile to live almost everywhere. Females lay around 3-8 eggs at time and the young leave the nest usually around 20 days after their hatching. Starlings are a pest economically because they often eat food provided for agricultural livestock and they damage cultivated fruits and vegetables. They are also a hazard to look out for near airports because they nest near airports can be sucked into jet engines. They also believed to further the spread of harmful diseases. Starlings also compete with many other birds for nesting ares. Where nest cavities were limited, starlings had severe impacts on local populations of native cavity-nesting species. They have caused several other species of birds to find new habitats because they were forced out due to the lack of nesting areas.

Africanized Honeybee- Steve Machi

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The Africanized Honeybee, Apis mellifera, is a hybrid of one of several European Honeybee species. This hybrid honeybee is almost indistinguishable between the common honeybee. One main difference between the Africanized honeybee and the common honey bee is that the Africanized bee will nest closer to, or under the ground. AHB are extremely territorial and aggressive as compared to their common counterparts. If their nest is threatened, they will swarm the threat to the nest with hundreds of bees repetitively stinging the intruder or passerby. A person walking within 50 feet of a nest can trigger an attack. A machine 100 feet away can also trigger an attack. The AHB will chase a victim up to a half mile. They cause major problems for any creature located near their nest. An economic impact is that it is very difficult to collect t honey from their nests. They were brought to the U.S. to increase honey production but now cause more trouble than benefit and therefore hurt the honey industry.