For me, conservation has a far broader scope than the natural habitat. When someone says "I conserve", it generally means they are making an effort to reduce their personal contribution to an environmental problem, be it habitat loss, energy consumption (and the unsustainable consumption of other natural resources including timber, fish, soil, minerals etc) garbage and pollution. Conservation is a way to translate environmental values into action. Where environment is the noun, conservation is the verb. And the verb has a myriad of applications!