Environmental conservation is important because we have only one planet. The planet is commonly shared by human and all other species. It provides all organisms with their necessities for survival and propagation.
According to The Nature Conservancy2, serious environmental damage often takes years to manifest obvious symptoms. Environmental conservation seeks to prevent dormant damage via measures including engineering technology, administration/legal, and education/propaganda etc.
Food chain preservation - Damage to a small or seemingly insignificant ecosystem often has deleterious effects on many others. For example, if industrial runoff upsets algae growth, it also impacts the creatures that rely on the algae for food. This, in turn, affects the natural predators of the algae eaters. Before long, the entire food chain incurs hardship.
Fossil fuels - Non-renewable and highly polluting oil and natural gas are the overwhelmingly consumed throughout the world, which seriously endangers the ecosystem. For example, oil pipelines often destroy important animal habitats. In the event of a malfunction or accident, submarine oil drilling and transportation also pose significant threats to marine animals and the overall aquatic environment.
If we do not adopt appropriate measures to protect the environment and to prevent consuming the resources over the planet’s carrying capacity, both human and other species would suffer at the end.
(Or other reasonable answers)