Ecology And Environment

Explaining Biodiversity Loss



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There may be as many as 30 million species in existence, most of which have not even been described. Extinction rates now are higher than ever, and some scientists estimate that we are losing one species per hour. The more species we lose, the less diverse our biological world becomes.

It is important to recognize that everything in the biological world is connected. Species depend on one another in ways that are often unrealized until something goes wrong. Each time a species goes extinct, overall biodiversity is reduced. Maintaining high levels of biodiversity is, therefore, important to assuring the balance of nature remains, well, balanced.

What are some major threats to biodiversity that we are facing today?

HABITAT DESTRUCTION AND ALTERATION
Probably the largest threat to biodiversity today is habitat destruction and alteration. In the tropical rain forest, large stands of trees are being cut and burned daily to make room for local agricultural endeavors. It has been estimated that some of these large trees can contain as many as 100 species unique to that tree. Felling hundreds of these trees in a day, therefore, can lead to extinction of many species before they are even identified. Habitats do not have to be entirely destroyed in order to be less suitable for life. Activities such as drilling, mining, and farming can all lead to conditions that kill plants and animals.

INTRODUCTION OF EXOTIC (NON-NATIVE) SPECIES
Each species has adapted to its environment through the process of natural selection, through many generations. Species that are exotic, or non-native, can infiltrate an area and disturb an ecosystem. Exotic species are generally better competitors, predators, and are more tolerant of harsh conditions, and so do better than native species. Kudzu, bullfrogs, and honeysuckle are all examples of organisms that have flourished in new habitats, all while squeezing out native species. Disease organisms are introduced in the same manner. While species can evolve to withstand disease outbreaks, new diseases or parasites to which they are not accustom have the potential to wipe away entire species. In fact, introduction of exotic species is thought of as being the second most common reason for loss of biodiversity.

COMMERCIAL EXPLOITATION
Human consumption and overexploitation can be responsible for the demise of species. Red-legged frogs were once abundant in the western US are now threatened because for decades humans collected them from the wild to eat their legs. Overharvesting of fish is becoming more and more common. Illegal trading of elephant tusks, bear gall bladders, and rhinoceros horns are all responsible for reducing numbers of these species.

GLOBAL CLIMATE CHANGE
Global climate change is becoming more recognized as a cause of biodiversity loss. Species that have narrow ranges or live in very cold climates (such as polar bears) will decline more and more rapidly as ice caps melt, temperatures get warmer, and precipitation decreases. While polar species are going to be the ones most prominently affected by climate changes, there are examples of Caribbean mangroves and sub-alpine forests that are already experiencing changes in species composition.

Why is retaining biodiversity vital?

Species perform critical biological functions, such as pollination, biodegradation and bioremediation, and water storage. Species serve as reservoirs of new genetic material including genes that can be transplanted into crops and increase yield or pest-resistance. Because only a small percentage of edible plants and animals have been domesticated, many new species are potential new food sources. Many species serve as biological control agents. Insect populations are held in check by species bird and amphibian species. Many plants and animals have byproducts that are useful to humans and can serve as natural pesticides or even medications (like poppies supplying opiates, or foxglove creating the heart medication digitalis). Lastly, some species are very sensitive and are sentinels of environmental degradation.

While species extinction rates are higher than ever, it is still within our power to slow or halt this process. It will require educating people in all walks of life, and a dedication to realizing the importance of preserving worldwide biodiversity.

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