| The President’s Hoot Richard H. Baker, Ph.D. October 2005 |
In my first botany course, I learned that a “weed” is a plant out of place. Some plants and animals that have been introduced, either intentionally or accidentally from somewhere else, are called “exotic”- not naturally found there. They can also be serious pests or “weeds” that invade our environment. An invasive exotic pest species is one that spreads naturally in natural or semi natural habitats, displacing native species, and to producing a significant change in composition, structure, or natural processes such as fire and water flow. Usually, an invasive species is self-sustaining and expands into populations within communities where they were not previously associated.
In Florida we have numerous exotics, but the most notable are Brazilian pepper, Australian pines, melaleuca and many vines. There are also numerous animals, for example, cattle egrets, Asian clams, Asian tiger mosquito, and many insects.
Our Earth is estimated to be 4.5 billion years old. Only recently, just 1.7 million years ago, one exotic species evolved in Africa, and began to spread into Europe and Asia. It crossed the Bering Strait only 15,000 years ago and within a few thousand years came down into Florida. During the last hundred years, it has become quite a dominant pest affecting the water supply, devastating beach communities, drying up wetlands, polluting lakes, oceans, and soils, daming and canalizing rivers, removing forests, degrading air, causing global warming, and eliminating numerous plant and animal species that have not even been described or named or even put on the endangered lists. It has eliminated all of its predators and is only subjected to a few viral, bacterial and parasitic diseases. It is now found in every continent and nearly every habitat including space and the Moon. There are now over six and half billion individuals with many of them starving and competing with each other even to death but still reproducing and living longer and longer. This species is even thinking of going to Mars to live, probably as a back up in case things really get out of control here.
Some hope and pray that this “exotic” will soon realize that it is a living species together with others on the planet and will learn to play by the natural rules that define how to live in balance with other species. This means this exotic would have to address “Sustainability.”
Our region and even the world will someday reach a limit of space and resources available for us. Sustainability from a scientist’s view means the carrying capacity of our environment. In ecological terms, the carrying capacity of an ecosystem is the size of the population or community that can be supported or sustained indefinitely upon the available resources and services of that ecosystem. Living within the limits of an ecosystem depends on three factors:
· the amount of resources available in the ecosystem;
· the size of the population or community; and
· the amount of resources each individual within the community consumes.
The concept of carrying capacity is closely related to the idea of “capital”, which fortunately many individuals of this species understand. The term “capital” is most commonly used to refer to money and material goods. However, in the context of sustainability, human communities have several different types of capital that need to be considered – natural, human, social, and built capital. Together, these types of capital are referred to as community capital. All four types of capital are necessary for communities to function. All four types of capital need to be managed by a community. All four types of capital need to be cared for, nurtured and improved over time. A community that is living off the interest of its community capital is living within the carrying capacity. A community that is degrading or destroying the ecosystem on which it depends is using up its community capital and is living unsustainably.
Carrying capacity is much harder to measure for human, social and built capital than for natural capital but the basic concept is the same – are the different types of capital being used up faster than they are being replenished? A community that allows its children and adults to be poorly educated, undernourished, and poorly housed is eroding its human capital. We need opportunities for rewarding work, healthy recreation, creative arts, physical and mental exercise, and entertainment. Gated communities that allow the quality of its social interactions to decline through lack of trust, respect, and tolerance is eroding our social capital. A city or county that allows its buildings, roads, parks, power facilities, water facilities, and waste processing capability to decay is eroding its built capital. In addition, city or county that allows its agriculture to disappear into high-density subdivisions, losses it ability to independently feed and clothe itself and then must rely on others to satisfy these survival needs.
As human beings, we need to control our population size, as our resources are finite even though our appetite is not. Otherwise, there is not room for fulfilling a new vision of striving for human greatness, the creativity and outstanding achievements that our culture could nurture. We will be so caught up with trying to handle all the problems that overpopulation will have that we will not be able to do better than we are. We will be lucky to just hold our own. Our environmental quality is in danger of being not only eroded but becoming toxic to all living beings.
Hopefully, we will not be the ultimate exotic weed.
