1. (20 points) Keystone species are critical components that keep ecosystems in balance. Large predators such as wolves, bears, and mountain lions often get a bad reputation for the danger they present to humans, pets, and livestock. It is even practice in some states to provide bounties for predator kills since these species are often blamed for destroying the ecosystem. As environmental scientists, we know this is inaccurate and in fact removing predators demonstrably harms ecosystems. Give an example of the negative feedback effect that can occur if a keystone predator species is removed. Consider all parts of the ecosystem from other animals to plants, soils, aquatic systems, disease, etc. You should address at least FIVE parts of an ecosystem that may be affected by the removal of the keystone predator and explain HOW those parts might be affected.
Example: If Species X is removed, small mesopredators such as Species Y might increase in numbers, which could increase Disease X….and so on, for FIVE components of an ecosystem.
2. (10 points) Community complexity is vital to a stable ecosystem. What might happen to an ecosystem where you remove that complexity and species diversity? What is an example of something that could go wrong if you remove complexity and diversity, and what is a possible consequence of that unfortunate event? You can use plants or animals in your answer. (Note that this is NOT a repeat of question 1. Question 1 asks about removing keystone species. Question two asks about removing ecosystem complexity and species diversity.)
3. (10 points) The idea of rewilding is an important concept in environmental science – essentially, giving anthropogenically-modified lands back to nature. One offshoot of the concept is Pleistocene rewilding, or the reintroduction of extinct megafauna into historical ranges (the most common examples are mammoths and saber tooth cats). Do you see problems with this, and if so, what? Consider what you know about ecological niches, species interactions, and shifting biomes.
