Saturday, September 11, 2010

Are we being stewards of the world?

Many scientists consider humans as the most invasive species, as humans can greatly change an environment and impact living things that reside there. Are we being stewards of the world? Take a look at an issue in which human intervention has positively or negatively affected the biodiversity of our ecosystems.

"The fundamental property of ecological systems is a certain mixture, or diversity of living things. . ."(1). Biodiversity, or the variety of living things that exist, is fundamental to the existence of life on Earth, and the importance of it cannot be underestimated. In the past few centuries, humans have had an especially negative affect on biodiversity, although, in general, are becoming more aware of its role. However, due to the damage we have caused, and the value that biodiversity has to us as humans, protection of the natural environment is necessary.

Biodiversity is an extremely important part of life on Earth. It is not only the variety of living organisms on our planet, but also the interdependence of all these living things, including humans. It creates and maintains ecological systems; the most recognizable of which are Earth's biomes, which can be divided into the broad categories of Forests, Tundra, Aquatic, Grasslands, and Deserts. Life is, in fact, one of the major features that differentiate biomes from one another. "Biomes are defined as 'the world's major communities, classified according to the predominant vegetation and characterized by adaptations of organisms to that particular environment' (Campbell)."(2). Without vegetation or organisms, these landscapes would be indistinguishable from one another. Clearly life plays a major role in the function of ecosystems, and the variety, or diversity, of this life has played a major role in the evolution of the world.
In evolutionary theory, it has become clear that the greater the diversity that exists within a family or genus, the more likely it is to survive environmental change. So, evolution depends on biodiversity. Ecosystems are being destroyed, animals and plants becoming extinct, and biodiversity is being lost due to increased human activity. Although environments would be shifting and evolving regardless of human influence, it is necessary to understand that humans are causing the rate of change to become particularly dangerous. Environmental conditions are changing so quickly that individual species as well as entire ecosystems are struggling, and often failing, to adapt.

Currently, there are many manners in which ecosystems and species are being negatively affected. The first is land use, which is most responsible for the current decrease in biodiversity. Much of the Earth's surface is covered by farm land (Shown below) and homes, a problem that is often overlooked. The most fertile soil is usually found in the best climates, which also usually happens to be where the largest amount of biodiversity is. The best example of this is in the tropics, where both tropical rainforests and cloud forests are being cut down and turned into "patchwork" farms. Furthermore, intensive agriculture is a growing concern. Fertilizers and pesticides used to treat crops harm land and drive animals away. Eventually, a given plot of farmland will contain too many chemicals to continue farming on, and the farmer will have to move to a new one, creating a vicious cycle of destruction of natural land.

Another threat to biodiversity is the loss and extinction of species. This topic is better known and publicized than the farmland issue, and many organizations are working towards the preservation of wild animals. However, it is important to understand that we need to pay as much, if not more, attention to reductions in species as extinction's. We often wait until a species is highly endangered before helping, at which point it is often too late. Endangerment occurs both directly by humans, such as fishing and hunting to excess, and indirectly, such as reducing habitats to the point where animals can no longer live.

Many pollutants travel incredibly quickly and cover a broad area. Long-term pollution is a great concern as well, even at low levels, because it can affect entire ecosystems through the chain of life. Furthermore, pollutants in soil and ground water cannot travel quickly, and thus do not filter out well.
Climate change is a growing concern as well, though it is somewhat debatable as to whether or not humans caused it. Natural changes in weather have had perhaps the greatest affect on biodiversity and ecological systems. This is shown with the picture below, of the penguin used to its natual habitat, and that being destroyed and trying to survive without the snow and ice. The threat of humans shifting the climate is therefore extremely threatening to the natural environment. "Were the average temperature to rise by several degrees Celsius, that warming would probably be followed by potentially large reorganizations of some ecological communities." (1).

One last issue concerning the affects that humans have on biodiversity is that of overpopulation. Recent advances in science and medicine have allowed for much greater life span and a very small infant mortality rate. We are increasing in population more rapidly than ever before. The growing population causes displacement of natural environments, not only because we need more living space, but also because the demand for agriculture and industry becomes higher as a result.
It is painfully clear that in many ways humans have had a significantly negative affect on biodiversity and Earth's natural environment as a whole. It is essential to realize that as rational beings, humans have the ability to not only understand the problems we have created and what needs to be done to amend them, but also the capability of accomplishing these tasks.
The natural environment provides services which benefit the economy as well. For instance, biodiversity helps keep water clean and naturally manages water flow and watershed. Trees and plants keep air clean through the constant transfer of carbon dioxide and oxygen, and overall biodiversity helps regulate climate.

Biodiversity is clearly a fundamental component of life on Earth. It creates complex ecosystems that could never be reproduced by humans. In the end, we all want and need biodiversity. Although we continue to harm the natural environment, often without realizing the impact that we have, an increasing number of people are becoming aware of the need to protect biodiversity. Hopefully humans will continue to pursue the issue so we can eventually live entirely with nature, not harm the very system that allows us to exist.