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The Apple Snail and other new residents

If you have ever watched any of the information channels on television you shouldn’t have failed to pick on the fact that thousands of species of animals, plants and insects are moving into new habitats.

With the increase in global temperature the range of individual species’ habitats are increasing and this is no where more apparent that in aquatic habitats.

A good example are the corals around Japan which are moving northward. One species has been moving about 14 kilometers a year – helped along by the ocean currents. Researchers say that this means ocean ecosystems could shift rapidly in the face of climate-change impacts.

Closer to home the Amazonian apple snails, which were only found in Mobile’s Langan Park, have now been found in a pond only one mile from the Mobile Delta. The apple snail is a voracious plant eater and has become a nuisance in Louisiana, Mississippi and Florida. In some areas, they have been blamed for wiping out up to 95 percent of the native aquatic vegetation. There is no telling what they would do to the delta.

The same is true with land animals too. In case you were wondering what was making that mournful howl at night it’s the coyote. The coyote (Canis latrans) has long been looked upon in the western states as a menace to cattle and sheep ranching. For years they were hunted, trapped and poisoned more or less with success but these activities never became a real threaten to the coyote. These removal measures ended in the 1960’s due to side effects like dog and child poisonings and the negative ecological impacts of removing a predator from the system.

Before 1900, coyotes were found primarily west of the Mississippi river. In the last 200 years, the coyote has extended its range to the eastern and southern United States. This expansion of habitat has been brought about by the actions of man with the opening up forestland through lumbering which has created open habitats preferred by coyotes and the extermination of many of the coyote’s chief competitors like the wolves. The predator control methods previously used may also have produced a surviving population of coyotes that are more alert, wary, intelligent and adaptable – Darwin at work. Coyotes are now found in many densely populated urban areas and seem to have assumed control of an ecological niche created by man. Mountains of garbage, uncountable numbers of rodents like rats and many places to den up define this niche.

The nine-banded armadillo (D. novemcinctus) is another animal that has humans to thank for expanding its range. Before about 1850 the nine-banded armadillo was not found north of the Rio Grande River. The sudden and rapid armadillo colonization of the southern United States has puzzled more than a few biologists. The rate of their range expansion per year is almost ten times the average rate for a mammal. Sightings of the armadillos are reported farther north every year. Armadillos are now found throughout the southern and southeastern United States to include Texas, Oklahoma, Kansas, Nebraska, Colorado, Missouri, Arkansas, Mississippi, Louisiana, Alabama, South Carolina, Georgia, and Florida. Armadillos migrated from Mexico into the southern states as members of traveling circuses. Armadillos were regular stowaways aboard trains and were part of a thriving pet trade for many years due to their novelty and docility.

Armadillos were helped in becoming established in their new range as ranchers and farmers spread southwest through the United States. The landscape was altered by farming and ranching that demanded regional rivers, formerly impervious to armadillos, be diverted or lowered for irrigation. Fire control programs converted grasslands that were once burnt over every few years into dense underbrush that armadillos prefer. Settlers displaced Native American cultures and used extensive hunting and predator control tactics against the black bear, red wolf and coyote.

The armadillo is apparently naturally resistant to parasites. It has non-specialized teeth and an omnivorous diet, eating just about any organic matter it can find. Females annually produce a litter of four, which are all genetically identical to one another. Females can delay implantation of fertilized eggs for up to 14 months after mating and they live approximately 20 years. A single female who is pregnant with male young can establish a long-term population in a new area.

Think Global – Act Local!


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