A recent study concluded that predators at the top of the food chain are important for the good of the environment, other species and for people. We have been busy killing them off and it has hurt ecosystems everywhere.
Why are predators necessary? Let's look at wolves in Yellowstone to see how nature works.
Throughout the US wolves had been routinely exterminated, poisoned and hunted for bounties until they were nearly extinguished in the lower 48 states. They were placed on the endangered species list, and in 1995 20 wolves were reintroduced into Yellowstone park in an attempt to bring back the species.
Without the wolves in Yellowstone elk populations grew to unsustainable numbers. The park became over grazed. Beavers, elk, and deer eliminated much of the vegetation along rivers and streams. This resulted in a decline in bird populations, there was more erosion, there was less shading and fallen trees to shelter fish, so they declined.
After the wolves were reintroduced, they began culling the populations of elk and deer of the sick and weak which strengthened the species. Vegetation returned along stream beds as did the birds, amphibians, and fish, and erosion was reduced and water quality improved. The wolf left larger portions of its prey's carcasses uneaten so other carnivores, like bear, coyotes, fox, carrion birds, and many other animals, were better able to survive the tough winters. The entire ecosystem improved.
The same is happening in the oceans. We have eliminated 90% of the large predator fish. Sharks are nearly being eliminated for their fins. "In the North Atlantic this resulted in a jump in the population of cow-nosed rays, which feed on shellfish and caused a collapse of the bay scallop fishery in the Northeast."
"And the hunting of sea otters decimated coastal ecosystems when kelp-grazing sea urchins, which the otters eat, multiplied and destroyed kelp forests. Those forests act as a kind of nursery for many ocean fish and other species harvested by people."
No matter what environment we look at the loss of the top predators have had remarkable effect on the entire ecosystem and may be one of the main reasons that so many thousands of animal species are going extinct in what scientists call the 6th great mass extinction. In the earth's history.
http://www.registerguard.com/web/newsloc...The good news is that it is not too late to bring them back. The wolf's reintroduction has been successful and is being de-listed in several states, that have protection plans.
http://www.scientificamerican.com/articl...Now many shark species in the Atlantic will be protected.
http://news.discovery.com/earth/hammerhe...And the protection of sharks and anti finning is catching on in the pacific.
http://news.change.org/stories/victory-f...The establishment of Marine reserves that allow no harvesting is proving to be a critical lifeline to the fisheries industry. Fish live as long as humans but unlike humans they become better breeders as they grow. The older and bigger the fish the more eggs they lay and the healthier the eggs and offspring. Therefore it is vital that we have marine reserves so some old fish can survive to replenish the species.
http://www.nasw.org/users/hickeyh/fat_fe...The same tactics may be necessary to preserve wilderness animals on land. Natural parks and wilderness areas act like marine reserves where species can thrive, but large predators like Grizzly Bears, wolves and wolverines, need room to roam and can range several hundred miles so when they wander from the preserves they are often killed. The best chance for returning some parts of the country to ecological balance is to provide connecting corridors between wilderness areas.
http://www.suite101.com/content/wilderne...Conservatives of course oppose reintroduction of predators to the lands. Many ranchers are opposed to it because of the predation of their livestock, but I think reimbursing ranchers for the few animals they loose is worth it to bring back at least a very small part of nature back into balance.
"Thousands of tired, nerve-shaken, over-civilized people are beginning to find out that going to the mountains is going home; that wildness is a necessity; and that mountain parks and reservations are useful not only as fountains of timber and irrigating rivers, but as fountains of life."
- John Muir, naturalist