How does agriculture impact our ecosystems?
While human population increases, food production should be increased therefore we want more agricultural land, cut down trees, alter rivers, etc.
For agricultural land demand, people tend to clear forests. Therefore, natural ecosystems lost. For palm oil, for instance, people convert natural ecosystems into palm tree plantations in Far Eastern Countries. Natural ecosystems have been diminishing in size and their functions. Often, this is irreversible.
When you open some places to agriculture, you need irrigation. Therefore, we build dams, reservoirs, etc. These buildings show their effects on aquatic ecosystems. Some fish species cannot migrate upstream if such buildings are erected. They disappear. Or such water bodies are contaminated due to agricultural chemicals accumulation. Therefore, water pollution becomes an issue.
We use lots of chemicals and agricultural aids. Even though these products help us improve our agricultural harvest, they might be harmful to water resources or natural air/soil quality. Their harm can be shown many years later (such as in the case of DDT). Therefore, natural life is harmed/damaged when we use such chemicals to improve our efficiency in agriculture.
There is a relatively new concern: genetically modified crops. Between 1996 and 2003, global acreage (genetically modified crops applied) increased from 4 million acres to 167 million acres.