The larger the human population gets, the more land we require. More houses must be built, more resources found, more food must be grown and more waste is produced. This often means less space and fewer resources for other animals and plants.
Often biodiversity is significantly reduced when land is cleared for human uses, such as building, quarrying, farming and waste disposal. Think about the reduction in biodiversity, which occurs when an area of rainforest is cut down to grow crops.
When farmers want to harvest crops, the hedges that are used to mark the boundaries of the fields can often get in the way of the machinery. The farmer's solution to this is to remove the hedgerows. The farmer can now easily harvest the crops, much more quickly than if he were to do it without machinery.
Hedgerows, however, provide food and shelter for a wide range of different animals. Birds, such as robins and blackbirds, rely on the hedges for their nests and to bring up their young safely hidden from predators. Hedgehogs and mice also use hedgerows to nest, shelter and hibernate. Without the hedges all of these organisms will suffer. Their numbers may decline and this has a knock-on effect on the rest of the ecosystem. It could therefore be argued that farmers are negatively interacting with the ecosystem.
Some hedgerows are now protected by the government and it is illegal to remove them. This helps to preserve this ecosystem for the organisms that depend on it.