A MODERN-DAY CAUSE OF COMPETITION AND EXTINCTION NON-NATIVE SPECIES A MODERN-DAY CAUSE OF COMPETITION AND EXTINCTION

What Are Native Species? Native species are those that normally live and thrive in a particular community. They occupy specific habitats and have specific niches in their native environment. They have natural predators that help to keep their populations in check.

What Are Non-Native Species? Species that migrate into an ecosystem or are deliberately or accidentally introduced into an ecosystem by humans.

Africanized Honeybee (Killer Bees) 1957 African honey be crossed with native honey bee to produce an overly aggressive bee in Brazil which escaped. Displaced the native honeybee through competitive exclusion and migrated northward at a rate of 200 miles per year. Northward migratory rate slowing down due to climate (frost). Will global warming allow their migration to move northward over time? Problems: They are so aggressive, they not only out-compete native bee populations, but pose great health threats to humans.

Geographic Distribution of Africanized Honey Bees in USA

Fire Ants Late 1930’s introduced by accident in Alabama in shiploads of lumber and cargo. Interspecific competition reduced native ant species by 90%! Fire ants are very aggressive and through direct combat reduced native species. Since there are no natural predators, they produced more colonies than native ants and increased their population density significantly in south.

Fire Ants Interference Competition – fire ants consumed food and invaded habitat of native ant species (competitive exclusion principle). They release sulfuric acid when they bite and can kill deer fawn, lizards, birds, livestock, pets, and human babies. Fire ants have invaded trucks and caused roadside accidents when drivers have been attacked. Chew through underground cables and disrupt electric and phone service and have started electrical fires in the south.

Fire Ants They are pesticide resistant (Directional Natural Selection of r-strategists) USDA (US Department of Agriculture) has introduced a non-native parasitic fly that deposits eggs on the fire ants. When the larvae develop, they eat the heads of the fire ant. CHAOS! $$$$$$$$

Fire Ant Distribution in the USA (Degrees Celsius)

Brown Tree Snake 1950’s arrived in Guam in wheel wells of airplanes Drove 85% of native forest birds to extinction. Highly aggressive nocturnal snake. No natural predators. Eats domestic animals, even small human babies.

Native Range of Brown tree Snake

Distribution of Brown Tree Snake in USA

Kudzu Vine 1930’s - imported from Japan and planted in the southeastern USA to help combat soil erosion following the Dust Bowl. 1940’s – US Soil Conservation Service (federal agency) paid farmers a subsidy to grow kudzu vine. Problems: No natural predators, very prolific reproduction. Costs USA government $500 million/year to eradicate! Possible Commercial Uses: Chemicals produced in the vine are used in Japan to combat diseases. USA found chemicals in vine may reduce alcoholic cravings. May be a source for paper products!

Kudzu Vine Distribution in USA

Invasive Species on Long Island Gypsy Moth – 1869, a French naturalist imported gypsy moths to Boston in an attempt to breed them with silkworms. Gypsy moth caterpillars escaped during the experiment. They eat the foliage of many hardwood trees, especially oaks and cherries. They continue to “hitch hike” rides via cargo into the USA. The current gypsy moth population can eat all of the leaves on 13 million acres of trees in 1 growing season!

Asian Longhorned beetle The beetle is native to China. 1996 Found in New York City and Amityville, Long Island. Believed to have come over in cargo pallets from China. Target trees: Norway, sugar, silver, and red maple. Will also feed on horsechestnut, poplar, willow, elm, mulberry, and black locust. Eradication: Must cut down, chip, and burn the trees. New Method: Central Park, New York City Parks Department injects “birth control” via hypodermic needles into the base of hardwood trees so that females will become sterile as they feed. This has significantly reduced the population in Central Park Problem: Cost lots of $ and requires many employees to administer and monitor populations. New York City Parks department exists on a shoe-string budget!

Asian Longhorned Beetle

Invasive Species in Green’s Creek Watershed Common Reed Phragmites australis

Purple Loosestrife Lythrum salicaria

Japanese Knotweed Polygonum cuspidatum

Oriental Bittersweet Celastrus orbiculatus

Garlic Mustard Alliaria petiolata

Bamboo

What Is Our Future? “ By reducing and degrading life’s support systems (Earth Capital), we could make our own species more vulnerable to extinction, or at least to a massive population crash”. If we are the most “intelligent” species on Earth, why can’t we follow the simple laws of nature?