One example of a fragile environment is the tropical rain forest.
Humans intervene in tropical rainforests in order to bring real or imagined benefits to themselves or the local population. The short-term benefits of clearing rainforest areas usually include:
land for agriculture, houses and roads
jobs for local workers in road building, logging agriculture, extractive mining, building etc
the generation of income (often in valuable foreign currency) where the rainforest is located, when wood, minerals, and other resources are sold.
Scientific investigation into the rainforest plants may provide new food sources and medicines.
These benefits, however, come at a heavy cost. Clearing rainforest threatens the survival of many plant and animal species and can lead to serious environmental degradation. Widespread deforestation damages the whole biosphere - the balance of living and non-living things on planet Earth - with serious long-term consequences for humans.
There are many other examples in the world of this type of risk to our fragile environments.