Many human activities cause pollution, habitat destruction and climate change, all of which are destructive to ecosystems. According to the World Wildlife Fund, the use of pesticides and fertilizers on farms has increased 26-fold over the last 50 years, which has caused increased damage to streams, rivers, lakes and the world’s oceans. Fertilizers are toxic to many types of aquatic life and they alter the chemistry of local waters.
Another way humans can harm ecosystems is through the introduction of non-native species. The National Wildlife Federation suggests that invasive species spread via the pet trade, on boats and along with imported ornamental plants. These invasive species can displace native species, altering the balance of the ecosystem. Invasive species take a number of forms, from large fish, such as Asian carp, to microscopic viruses, such as the West Nile virus.
Improperly dealing with solid waste can cause a number of problems for aquatic ecosystems. The World Wildlife Fund explains that large accumulations of plastic can form in the ocean, which may release harmful chemicals in the water, damage coral reefs or harm animals that inadvertently ingest it.
Air pollution also harms natural ecosystems. According to the World Wildlife Fund, acid rain, caused when humans release sulfur dioxide in the air, is also harmful to the world’s natural habitats.