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)

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

Bamboo

Wooly Adelgid

Native to East Asia First found in VA in 1950’s Decimating Hemlock population No natural predators Hemlock has no defense against

What Are Indicator Species? Indicator species serve as early warnings of damage to a community. Birds and butterflies are migratory and are excellent indicators of the environment. They do not return to areas along their migratory routes where deforestation has occurred or where broad spectrum pesticides have been applied. Amphibians are also a universal indicator of environmental degradation as they respire through their skin.

Why Are Amphibians Vanishing? Appeared in the fossil record about 350 million years ago. Frogs and toads have been around for 150 million years (indicates adaptability) Last 20 years nearly 3,000 species of frogs and toads have disappeared.

Reasons for Global Amphibian Declines Global climate change (Costa Rican golden toads) Dehydration weakens amphibians, susceptible to fatal diseases. Introduction of non-native predatory fish into aquatic habitats. Pollution (air, water, soil)– respire through skin. Consume insects that take up pesticides (bioacumulation/biomagnification). Eggs sensitive to increases in UV radiation – endocrine blockers) Consumption of frog legs (delicacy). Loss of habitat.

Indicator Species As indicator species, amphibians may be sending us an important message about the health of the global environment. They don’t need us, but we and other species need them. Golden toads – once prevalent in Costa Rica’s cloud forest have disappeared.

Indicator Species on Long Island

Why Should We Care About Indicator Species? They give clues that the environmental health is deteriorating in parts of the world such as habitat loss and degradation, pollution, UV exposure, and climate change. They provide ecological services (niche) in biological communities. ie. Amphibians eat more insects including mosquitoes than birds. They provide a food source for higher trophic levels. Amphibians especially provide a storehouse of pharmaceutical products waiting to be discivered (economic goods and services).

What Are Keystone Species? A keystone species holds a community together, when it disappears, so does the biological community. Elimination of a keystone species dramatically alters the structure and function of a community.

American Alligator – a Keystone Species Largest North American reptile; only humans are their predator. Hunted nearly to extinction for exotic meat, and leather to make shoes and pocketbooks, and for sport.

Ecological Niche of American Alligator Dig gator holes that collect freshwater during the dry season which serve as refuges for aquatic life, and supply freshwater and food for many animals.

Ecological Niche of American Alligator Alligator nesting mounds serve as nesting and feeding sites for herons and egrets

Ecological Niche of American Alligator Alligator eat large numbers of predatory gar fish and help maintain healthy numbers of game fish such as bass and bream.

Ecological Niche of American Alligator As alligators move from gator holes to nesting sites, they keep areas of open water free of invading vegetation. This helps to maintain healthy ecosystems with flowing water.

American Alligator Protection In 1967, the US Government placed the American alligator on the Endangered Species List, which protected it from hunting. By 1975, the American alligator populations rebounded successfully.

Status of the American Alligator. In 1977, the US Fish and Wildlife Service (DOI), down-listed the American alligator to a threatened species in Florida, Louisiana, and Texas. Limited kills with a license are permitted. Recreational lotteries are held in the Florida Everglades each year by FWS. Alligator farms established to fulfill the market for alligator goods.

Why Should We Protect keystone Species? They play critical roles in the cross pollination of angiosperms (bees, hummingbirds, bats). Top predator keystone species help regulate the population numbers of other species. The loss of keystone species can lead to population crashes and extinctions of other species that depend on it for ecological services.

E.O. Wilson “The loss of a keystone species is like a drill accidentally striking a power line. It causes lights to go out all over”

The Good News Is… Conservation Efforts on the rise – President Theodore Roosevelt ( ) “the Golden Age of Conservation” 1903 he established the first federal refuge at Pelican Island off the east coast of Florida to protect the endangered brown pelican.

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?

What Can You Do? Education Participate in local groups to conserve the biological integrity of ecosystems Promote local economic growth while thinking globally Refuse, Reduce, Reuse, Recycle Shop locally, think globally (be an educated consumer) GET INVOLVED AND TELL A FRIEND