Extinction is Forever Compliments of Dean Henson, Naturalist at Pine Mountain SRP
It’s a certainty that somewhere out there at this very moment, the last dozen or so members of an ill-fated species are living on borrowed time. Formerly plenteous in number, the sad remnants of a defenseless life form live out the twilight days of their time on earth before vanishing forever.
What brings living things to this lowly state? How does a species that may have thrived for thousands of years in their present form come to be threatened, endangered and eventually extinct? The short answer is easy; most likely, their habitat changed. Once animals have settled into a niche through a series of gradual adjustments and have become adapted to a habitat they are best suited for, it’s difficult to become rapidly acclimated to anything else.
To begin to understand we must first realize that nothing in nature is static or constant; nothing, that is, but the element of change itself. Natural communities are constantly changing and transforming in a process known as succession. Very simply, communities succeed one another, each one better adapted, and more fit to the conditions of the site where they reside. A prime example is the narrative of forest succession. Consider the changes necessary to move a plot of earth from bare ground to a mature hardwood forest. Weedy plants establish a foothold and make the soil fertile enough for perennial plants to get started. The perennials then stabilize and enrich the soil so that shrubs can introduce themselves. The weeds are shaded by the shrubs, thereby encouraging tree seedlings to root, eventually shading out the shrubs.
Even these trees are not destined to stay in control for long, for an understory of shade tolerant trees will gradually overtake them. This climax forest is more stable than most, but far from static. There’s always the possibility of a lightning stroke on a dry afternoon that may start a raging forest fire and begin the entire succession process all over again. So the only thing we can predict in nature is the aspect of change; what form or direction in may take always remains to be seen.
With changing plant communities, there are always associated animals that rise and fall with them. The jilted species may attempt to survive by moving to another habitat that fulfills their needs, if there is one. Sometimes, there’s nowhere else to go.
We humans alter natural habitats by our continuous activity upon the landscape. While the end-result is the same, it seems more disturbing and less acceptable to consider extinctions that may have resulted from the selfish and inconsiderate acts of man when compared to extinctions that have resulted in response to natural change over great periods of time.
Natural extinction has been occurring almost since the dawn of time. From the beginning, species have succumbed to slowly changing environments and have given way to better adapted ones to take their place.
This is acceptable because the new species is a better genetic product than was its predecessor. In contrast, human-caused extinction events are dramatic and sudden; allowing no time for adaptation and the chain of adaptive change is broken.
When we lose a species from planet Earth, we also lose the free service it was undoubtedly performing in the ecosystem. If the lost species were an animal that buried its food, it may have unwittingly planted acorns that would grow into mighty oaks. If the lost species were a predator, its prey species may experience a population explosion that might lead to increased competition for food, that could result in the loss of certain plant species in the host environment. Then, being short of food, illness and disease may descend, potentially resulting in a mass die-off of the prey species, as well. Nothing in nature stands alone.
It’s currently estimated that the diversity of life on our planet today numbers nearly 9 million species, with about 6½ million on land and 2¼ million in the sea. With this vast array of plant and animal life, why should we be concerned with the loss of a few species? One reason is that much of the extinction now occurring is resulting from the impact of a single species – Homo sapiens. During the ages before man, species became extinct at a rate of about one every 1,000 years. By 1950, the loss had increased to one every 10 years. By the 1980’s the rate had increased to one every year, in the 1990’s, one a day, and today, this very day, three species are lost every hour.
We humans have much to lose, but we may never really know just what we’ve already lost. Nearly half all our medicines are derived from plants and animals, but only a small percentage of species have actually been tested to search for possible benefits to humans. Even seemingly abundant species of today may become challenged in the future or disappear altogether.
Extinction is forever. American naturalist and scientist, William Beebe once said, “…when the last individual of a race of living things breathes no more, another heaven and another earth must pass before such a one can be again.” May our awakening awareness nurture us toward better stewardship for the sake of all living things, great and small.
