As a species humans have an unfortunate habit of forever altering their environment. In many ways this is a good thing. If, over the ages, human beings did not undertake the alteration of their landscapes to enable them to be sheltered, to grow food crops, to establish areas protected from the ravages of nature and the creatures we share the landscape with, we would never have ventured beyond our early beginnings as crude creatures of the forest.
The problem is we never quite understand the potential for unpleasant outcomes when we should hesitate before embarking on new ventures that often have a habit of creating a situation we would prefer not to deal with. We bury history and arable land, and make refugees of countless people when it is decided to construct huge dams. And those dams are often enough not quite in tune with the landscape to the extent that they are not immune to massive flooding.
We cut down forests for use as firewood as populations increase and have need of fuel, and the great swaths of forest eventually diminish with the end effect of soil degradation, and winds carrying off the top layers of rich soil, leaving desertified areas behind. Increasing the likelihood of ongoing erosion, leaving little bulwark between ocean and land, mountain slides and valleys. The world's deserts are on the increase, while its valuable forestlands are decreasing.
We introduce, through inadvertence, through ships' ballast, creatures of the sea and the forests to parts of the world other than those to which they are native, and these introduced species, be they fish, crustaceans, beetles or viruses, thrive because there are no natural predators to keep them in check as they wreak havoc, establishing themselves firmly and in the process devouring or otherwise destroying native species.
A recent, truly interesting discovery reveals that Central Asia was the locus for the ancestors of all the apple trees that are now grown throughout the world. Scientists at Oxford University, using DNA, have established that Kazakhstan, close to the border of China, once hosted a myriad of forests of fruit-bearing trees, the apple among them. (Gardeners have reason to be grateful to China, Turkey and other eastern zones for many of the exotic and now-common species of flowers we enjoy nursing in our gardens, the world over.)
But in the instance of the areas of Kazakhstan, and the original fruit-bearing trees in great tracts of forests in the Trans-Ili Alatau range, about 80% of the apple forests have disappeared. Not, certainly, of their own biological volition, surrendering to environmental change, but because of the interference of humankind. During the Soviet era, Kazakhs were ordered to settle and form collective farms. Formerly nomadic, their new static conditions created a state of famine.
The people began to strip woodlands for food and firewood. And Stalin targeted the Russian botanist Kikolai Vavilov - who had surveyed, identified and gathered fruit specimens in the forests - whose expertise would have identified the problems inherent in this situation, to be exterminated. Finally, when Nikita Khrushchev ruled the USSR, the land was cleared for collectivized, intensive farming.
A minuscule fraction of the original fruit-tree forests now remain. The government of Kazakhstan is currently in the process, with the assistance of the UN Development Program of establishing a conservation project in the Zailijskei Alatau mountains, of the Tian Shan range. Where holiday villas for the wealthy continue to encroach on the landscape.
In North America botanists and environmentalists cope with the depredations of the mountain pine beetle, ravaging the vast boreal forests of British Columbia and Alberta. In Canada and elsewhere, the Dutch Elm disease took its toll of the continent's grand old elm trees. The Spruce budworm, the Ash borer, were all introduced to North America as alien species, now decimating the landscape.
In Maryland (U.S.) a truly fearful predator, the Northern Snakehead, whose origin is China, has found its way into the state's waterways. With no natural enemies, it is poised to destroy native fish, and is highly adaptable to new surroundings, capable of surviving for up to 4 days out of water, travelling by wiggling over land to new ponds, swamps and streams. Should it become successful in its spread, it could inhabit waterways virtually anywhere in North America.
Zebra mussels, another invasive species from the far East, has presented as a problem in the Great Lakes system of North America. They're filer feeders, leaving fish and other aquatic organisms without food, taken by the voracious and highly reproductive mussels. No other aquatic life feeds on them, thanks to their hard shells, and they're responsible for the disappearance of zooplankton forming the diet of many native fish. When the mussels interact with gobies - yet another noxious exotic headache - the conditions to produce botulism occur.
When some bright soul in the South-Eastern United States thought it might be interesting to introduce a common vine grown in Japan to the American south-east, another catastrophic situation occurred, where the fast-growing kudzu grew luxuriantly over other botanical species, overwhelming trees and shrubs with their presence, and impeding photosynthesis for the native species. Eradication programs have proved to be spectacularly unsuccessful.
We little envision the harm we do when we insist on interrupting nature's balance, and then reap the harvest of disaster.
Labels: Environment, Human Fallibility, Nature