Grassland and conifer forest have effective fire prevention program, what's the result of this?

a) succession to a deciduous forest


b) the preservation of endangered species in the area


c) an increase in species diversity because fires are prevented


d) no change in the species composition of the preserved community


e) a change in community composition because fires are natural disturbances that maintain the community structure

Grassland and conifer forest have effective fire prevention program, what's the result of this?
This seems like a poorly worded question, and the professor should get a D for making it.





a) is wrong. Grasslands, conifers forest, and deciduous forest can each be the final state for their local environment. For example, grasslands reign where there is a dry season that is too severe for trees to survive. Conifers can grow at higher elevations on mountains than deciduous trees, because conifers have turpentine, which is a natural antifreeze.





b) can be true. If the environment is not changed by fire, then species that live there can keep on living there.





c) should not be true. Species are diverse because they have to adapt to different local environments and circumstances. When a fire burns off the grass, or the underbrush, then that changes the local environment, and different species will have a temporary advantage to florish. So, fires increase diversity.





d) can be true for the same reason that b) can be true. No change lets things stay the same, by definition. This can be true, only if there has always been fire suppression. For example, when humans do fire suppression, this is a relatively new change to the environment, and we screw it up. The fires get worse every year because we let the underbrush and tinder build up until we have bonfire waiting to happen.





e) is true. Also, it shows that the question was probably a hypothetical "what-if" question.





Regarding e), biologist know that some mature conifer trees produce pine cones that will not open until a fire dries them out and makes them open. So some conifers need a forest fire to reproduce. This works out well, because after a forest fire, there should be some open spaces where a seed can take root, instead of being smothered by other plants. So the answer is that fires are a natural disturbance (lightning strikes have been around since the world began). Fires maintain the community structure because the community is already adapted to them. (Without fires, that species of conifer trees would never reproduce and the community structure would change.) After a fire, there is a temporary change in community composition because new grass or new trees can find a place to grow. With fresh green growth, different insects get a chance to florish because they eat the new growth. And so on, up the food chain.





Ok, to answer the question.


e) is your correct answer (from the long term perspective) Grassland and conifer forests have evolved with natural fires. The fires have helped to establish the current (long term) structure and composition of grasslands and conifer forests. If grassland and forests had an effective fire prevention program (like getting stupid humans to spend $billions to stop natural fires), then that would be an environmental change, and anything that lived there would have to adapt to the new situation. Hence, the composition and community structure would change. One of the changes would be (and is being caused by humans, now) that certain species of conifer would not be able reproduce without the forest fires. This generation would be their last, and that species would become extinct.





So, assuming that this is a "what-if" question (i.e. what if the question were suddently to be true, what would be the result?), then the answer is e). With a new fire suppression system, the grassland and conifer forests would change.





If the question is not a "what-if" question, then the question is just stupid, because the premise of the question is false and the question, itself, is false.