Threats to biodiversity
Every day, nearly 100 species go extinct, and more than half of Germany's plants and animal species are threatened today. Many scientists believe that human interference in the natural world is currently causing a new mass extinction on earth. Among the biggest threats to biodiversity are
- loss and destruction of habitat
- introduction of invasive species
- overexploitation through fishing, hunting and commercial trade
- pollution of ecosystems
Scientists view habitat loss and the introduction of invasive species as the two greatest threats to biodiversity, which is why these two are discussed in more detail below.
The introductory text "Biodiversity threats" discusses human impact on the earth's ecosystems, provides a bit more detailed information on the threats mentioned above and introduces the terms environmental carrying capacity and ecological footprint. A worksheet on the ecological footprint can also be found under the chapter sustainability.
The unit on invasive species explains how introduced species can threaten native wildlife. This topic is ideal for students to improve their skills in independent research by looking into invasive species in their region/country. Students will pretend that they have been hired by a conservation agency to create posters or information cards on invasive species in Germany that will be handed out to visitors of nature reserves and local parks. The document "Wanted - Invasive species" gives an example of such an information card (Asian lady beetle) and a blank information card that can be handed out to students for their research. Helpful websites for research on invasive species in Germany are also included in the instructions for the exercises.
The worksheet "Habitat destruction" especially focuses on the issue of habitat fragmentation and the attempt of conservationists to solve this problem by the help of wildlife corridors. Also related to this topic is the BUND's project "Rettungsnetz Wildkatze", on which you can find more material, including a great computer simulation if you click here.
After learning why small habitats (or habitat fragments) are a threat to many species, students are then given the option to pick between several possible wildlife refuges for a deer population. Depending on whether they opt for the refuge with the smallest edge, largest area or something in between, the students will have to use what they learned from the text for their argumentation.