Canada is not only a large country but an ecologically diverse one as well. Canada borders on three oceans, contains vast areas of boreal and temperate forest ecosystems, mountainous ecosystems, arctic ecosystems and prairie grassland ecosystems to name a few. These ecosystems support numerous human activities such as agriculture and forestry upon which the country's economy heavily depends. While selective activities can be leave no impact and others help restore ecosystems, generally the integrity of Canada's ecosystems is threatened from many kinds of human activities originating from both within and beyond the ecosystem borders. The scientific knowledge of ecosystem processes and changes, although meager, is gradually improving. Despite that situation, society is attempting to implement various measures to conserve and protect entire ecosystems and their components so they will continue to sustain themselves and provide for future generations.