the protection of plants and animals, natural areas, and interesting and important structures and buildings, especially from the damaging effects of human activity

wildlife conservation 野生生物保护

a conservation area 保护区

carefully using valuable natural substances that exist in limited amounts in order to make certain that they will be available for as long a time as possible

the conservation of coal/gas/oil reserves 煤炭／天然气／石油储量的保护

Energy conservation reduces your fuel bills and helps the environment. 节省能源能减少你的燃油费，而且还有利于环境。