Biodiversity threats
Today, we humans are the major forceof the loss of biodiversity,or rather we are the cause for most forces that lead tothe extinction of species. Ever since the Middle Ages, the human population has grown exponentially, and according to the United Nations, the world population reached 7 billion people in October 2011. It is obvious that we can’t grow exponentially forever, because our planet has an environmental carrying capacity:
In terms of population growth, we humans represent the species and ourplanet the environment: at some point, the earth won’t be able to provide every human with enough habitats, food and other resources. In a way, our human’s ecological footprint shows that we already live beyond our means. The ecological footprint calculates how much area of the earth‘s surface is needed to maintain our lifestyle (energy, raw materials, nutrition, all products we consume). As of today, we use ≈ 20% more than the earth can provide us with, which means that we would technically need a new planet earth within the next 50 years.
There are many threats to biodiversity, most of which are results of human behavior and our way of life. You should keep in mind that most of the time, not one but rather the combination of several reasons causes a threat to a certain species. Here is a list of some of today’s major threats:
1)Habitat destruction
2)Invasive species
3)Exploitation
4)Pollution
5)Climate Change
Habitat destruction occurs every day and everywhere on earth. Wherever we humans go, we destroy natural habitat: by cutting down forests, by building more roads and houses or by polluting ecosystems. Wherever habitat is lost or changed, biodiversity is lost. Conservationists rank habitat destruction as the most powerful threat to biodiversity.
Invasive speciesare animals or plants that inhabit a place where they originally do not belong. When an invasive species is introduced, it has to compete with native species for resources and habitat. Invasive species have the ability to adapt to a wide range of habitats, and because they are such good competitors, they often drive native species to extinction.
Overexploitation (sometimes also called commercial exploitation)occurs, when humans “use” plants or animals faster than they can recover. Our oceans are so overfished that many fish populations have completely crashed, and many animals have been hunted to extinction. Pet trade or trade in animal parts (such as ivory from elephant tusks) also contribute to the loss of species.
Why pollution and climate change are a threat to biodiversity is more or less self-explanatory: due to these factors, our ecosystems are not only being destroyed, they are also changing so rapidly that many species don’t have enough time to adapt to the changes in their surroundings.
Tasks:
Pick an endangered species and find some general information on it (common and scientific name, appearance, habitat). Questions you should also be able to answer are
- Why is it threatened?
- Is it protected? What is being done to protect it?
Websites with information on threatened or endangered species in general:
(German)
(English)
Websites with information on threatened or endangered species in Germany:
(animals that are protected in Germany)