Endangered Species

Say the phrase "endangered species," and many people scoff, thinking of government boondoggles that save obscure plants and animals at the expense of human economics. What many skeptics fail to realize, unfortunately, is that the balance of Earth's environment can be so upset by the extinction of the tiniest species that the survival of everything on earth can be threatened. In other words, thanks to their reckless mismanagement of the planet, humans are now an endangered species themselves, even though most of them don't realize it.

Endangerment is actually a very broad issue. It involves the habitats where Earth's plant and animal species interact. If there were any one thing that could reverse the rate of endangerment and extinction, habitat protection might be the key element among several contributing factors.

Habitat destruction matters so much because Earth's environment changes constantly. Ordinarily these changes occur gradually, giving species time to adapt to the shifts in their environment. When changes come rapidly, however, species have no time to react, and many of them die off because they can't adapt fast enough. Paleontologists estimate there have been at least four mass extinction events in Earth's geological history, and some say that we're currently in the midst of a fifth mass extinction because of the rapid loss of habitat.



Humans are causing the biggest, fastest changes in habitat. There's hardly a region of the Earth that has avoided the effects of human activity, especially since the Industrial Revolution began around 1750. Deforestation for human use has caused the immediate destruction of plant and animal habitat, followed by the loss of microbes in soils that formerly supported forests, along with the extinction of fish and other aquatic species from polluted runoff. Global climate changes that are depleting habitats also are resulting from human activities.

Individually, humans can't recognize how much they've endangered the world's plant and animal species. However, on a global scale, it's much easier to see how much human activity has depleted natural habitats. What's more, it can take centuries to regrow these habitats, if they can be restored at all.

Another way that humans endanger plants and animals is by the introduction of exotic, non-native species to a geographic area, either by accident or intentionally. In one of the episodes most familiar to residents of the American South, a type of vining plant known as kudzu was imported from Asia in the early 20th century. Without its natural predators to keep it in check, kudzu proliferated through the South, pushing out natural species and becoming a nuisance in some places and a menace in others. Another such example is that of a non-native water plant, the water hyacinth, which after a century has so clogged waterways in the American South that they're virtually unusable any longer.

Other factors in the endangerment of species include overexploitation, such as unrestricted whaling in the 20th century. The clear-cutting of old-growth forests in the western United States was another such instance of overexploitation that has since been mostly abandoned, now that its hazards are known. However, species remain threatened because of a brisk trade in several areas of Asia for items such as rhinoceros horns, sharks' fins and tiger bones.

Endangered species around the world face the same predator: humans. Ironically, humans also can be the savior of these endangered species by protecting them and their habitats.