The Clock Is Ticking, Extinction Or Survival?
Kilbee Brittain and Patricia Meyer
Greater Los Angeles Zoo Association.
“Ecology” is an every day word now. We use it in easy conversation, talking about “ecologically friendly detergent”, for instance. But what are we really saying?
Ecology comes from two Greek words: the “eco” part meaning our house, our home; and, the “log” part meaning logic, or, wisdom. So: ecology means the wisdom about our home our Earth.
The word was coined in this sense by a German zoologist in the late 1800’s. Since our environmental movement took off like a rocket with Rachel Carson’s 1962 Silent Spring (building on many teachings of the past, from ancient scriptures to western traditions like the teachings of Francis of Assissi and Albert Schweitzer’s medical, musical, and missionary teachings of “reverence for life”, to current efforts to preserve habitats and animals while accommodating needs of exploding human populations) the efforts of individual people like docents make a huge difference.
The individual docent has great influence in ecology. Every teacher counts. Some people in our Western societies still subscribe to beliefs that humans are separate from the rest of nature, and have a right to dominion. Other people of some Eastern philosophies see humans as part of a huge web of interdependent life on Earth.
What do you think?
What we think should, at least, direct our behavior, though we all know behavior doesn’t always follow belief. The health of nature on Earth depends on our answer about ecology how to maintain the wisdom about our home.
While in training, Los Angeles Zoo docents receive education that enables them to impart to Zoo patrons the need for conservation. In their ecology lessons, the stories of two canine species that are exhibited at the Los Angeles Zoo are used to illustrate how humans have destroyed the natural ecological balance of an ecosystem. In each case, this has resulted in low populations of the species, with the viability of the current populations remaining in doubt.
The two canines are the island fox, found only on the California Channel Islands, offshore from Los Angeles and Santa Barbara, and the grey wolf population in Yellowstone National Park.
The island fox
The island fox is found on six of the eight California Channel Islands – three of the five islands in the north forming the Channel Islands National Park, and also on the southern islands of Santa Catalina, a residential island, on San Clemente and San Nicholas islands, both owned by the United States Navy.
The ecological island fox study concentrates on the population on the three northern islands, where it has plummeted to approximately 170, split between three distinct sub-species, all but 75 managed in captive breeding facilities by the National Park Service.
The island fox is 20% smaller than its closest relative, the mainland grey fox, being the size of a housecat and weighing only three to four pounds. It is one of the least known and most endangered United States mammals. Four of the sub-species are being considered for protection under the United States Endangered Species Act.
The decline of the island fox was noticed by Channel Islands National Park researchers in 1994, but their observations could not pinpoint a cause for the deaths of the foxes. Many tests were performed but as no whole carcasses were being found, the Park Service knew some unknown predator was involved. Eight foxes were captured and radio-collared and the culprit was determined when a golden eagle feather was found near a partly destroyed carcass.
On the northern Channel Islands, bald eagles had previously reigned, preventing the infiltration of the golden eagle with their territorial behavior. The bald eagle does not prey on the fox, but on marine catch. This diet was contaminated during the 1950s and 1960s with the widespread use of the pesticide DDT which was ingested by the bald eagle in its fish diet, causing it to lay eggs with extremely thin shells, which broke easily before they were hatched.
The destructive qualities of DDT were recognized and its use banned in 1971. Although mainland populations of bald eagles have recovered, as DDT still persists in the marine food chain off the coast of Southern California, the bald eagle has not naturally repopulated the California Channel Islands.
The loss of the bald eagle allowed the golden eagle to visit to hunt on the Channel Islands, at first concentrating on the ready supply of introduced domesticated pigs that produced many tasty piglets. The island fox, living along with the pigs, and knowing no predator, was an obvious addition to the golden eagle diet. The foxes’ decimation had begun. Their natural cover of native shrub land had been eliminated by the feral goats, another introduced domestic species, so they were extremely vulnerable as they carried out their diurnal activities, easily visible to the golden eagle.
The National Park Service recognized that the island fox population would not survive unless they intervened, and captive breeding facilities have been initiated and are managed on three islands. The Park Service is committed to saving the island fox, becoming extremely active in removing the golden eagles by trapping and removal to northern California. Plans are in place to remove all feral and domesticated species that disrupt the natural ecological balance of the islands. Foxes cannot be released from the captive breeding facilities until the golden eagles are completely eliminated, so the story continues. In addition, the Park Service has returned bald eagles, with several eaglets returned to Park Service-built eagle boxes where they were fed, before release.
Each eagle is radio monitored and their survival and successful introduction is carefully followed and managed by the Park Service.
The future of the island fox remains in doubt, but with successful breeding in the captive breeding facilities, and the commitment of the National Park Service to save this tiny canid, a viable population may reoccur upon the restoration of the ecological balance on the islands.
The Grey Wolves in Yellowstone National Park
In the early 1900s, wolves were being exterminated throughout most of the United States, the last wolves being removed from Yellowstone National Park in 1922.
It was not until January 1995 that their reintroduction to Yellowstone became a reality. The wolves chosen for reintroduction were from Canadian packs. Fourteen were trapped in Alberta, Canada, and after full physicals and immunizations, were flown to Yellowstone, where they were trucked into the Park on January 12th, 1995, with hundreds of cheering fans lining the route. They had been absent for almost 80 years, and their absence had caused severe ecological imbalance.
The wolf is the top predator, and as such stimulates evolutionary adaptations for survival in prey species, acting as an agent of natural selection. The loss of a top predator changes the path of evolution and will change and jeopardize the strength of other species.
Soon after the wolves were released into the Park, researchers noticed a complete change in behavior and feeding habits of many species. The wolves found prey plentiful and quickly left many partly eaten carcasses, which provided food for grizzlies, coyotes, bald eagles, ravens, many beetles, and many bird species that fed on the insects. The populations of these species are now stable and healthier due to the return of an important ingredient of their diet.
The elk population was 56,000 strong at the time of the wolf reintroduction, and had been blamed for the overgrazing of Yellowstone National Park. The loss of vegetation had reduced insect populations, and therefore bird populations. The willow trees had declined, so the beavers that used them as building materials were gone. The riparian vegetation was stripped, and no longer provided covered feeding areas for the grizzlies that foraged in the spring at the end of hibernation.
The elk have moved to higher, open areas, now huddling in large packs upon the appearance of a wolf pack. Their population is stable and healthier, with the wolves taking the sick and weak members, strengthening the genetic pool.
The coyote is the animal most affected by the return of the wolf. In its absence they had proliferated, with bountiful prey, into large packs, inhabiting prime denning areas previously occupied by the wolves. Within two years of the wolves’ return, their numbers were halved, as they are killed by the wolf, if found in its territory.
The coyote now occupies poorer habitats, often relocating their dens in a constant state of turmoil and upheaval. But coyotes appear to adjust, their population has steadied, and they are healthy due to their use of the wolf-killed carcasses, at which they wait for their feeding turn after the wolves have eaten their fill.
The coyote population decline has allowed the rodent and small mammal populations to proliferate, with pocket gophers, ground squirrels and voles now available for the raptors, the great horned owls and the red tailed hawks, which have returned to the Park in greater numbers. The increase in rodent numbers has resulted in the return of the red fox to the Park. Pine martin, badger and pronghorn populations are more stable due to less predation by the reduced coyote population.
Researchers have enjoyed many years of wolf study, observing pack behavior and size changes due to the proliferation of prey. The wolves have drawn countless tourists to the area, where the wolves remain the stars of the Yellowstone ecosystem.
Their future of the wolf remains in doubt. The success of their reintroduction and increased population throughout the United States has prompted the U.S. Fish and Wildlife Service to consider the lessening or removal of the grey wolves’ protection in certain areas under the U.S. Endangered Species Act.
The reintroduction of the wolf and its presence in our country is opposed by many. If the Endangered Species Act protection is removed, the population could be reduced and another ecological disaster provoked. The research being carried on in Yellowstone National Park is proving the importance of the balance of an ecosystem, and what happens when humans interfere with that balance. The health and strength of the wolf, being the top predator, is an indicator of the integrity of the entire ecosystem.
An ecologically balanced ecosystem works perfectly. When humans interfere everything becomes unbalanced. Los Angeles Zoo docents learn this balance, and its importance, and can impart its significance to all visitors, in an effort to educate the public about nature and our place in the natural world.
In the words of the Scot John Muir “When we try to separate anything, we find it hitched to everything else in the Universe”.