Just as conservation of a species does not work in isolation from its ecological system, neither can a patch of habitat be conserved in isolation from the ecological system — the landscape of which that patch is a part. Populations of various species survive by meeting their ever-changing set of needs – food, nest sites, shelter – by moving among an array of patches of various habitats in an environmental mosaic to find those vital resources. To a landscape ecologist, that mosaic is a landscape and is a realistic scale of ecological study. Unfortunately, for some species, the scale of that mosaic may be huge. For the porcupine caribou herd, 4000 kilometres, through Canada’s Mackenzie and British Mountains and back to calving grounds in the Arctic National Wildlife Reserve. For arctic-nesting shorebirds the mosaic extends to South America. For a grizzly bear, the scale is usually larger than the park or reserve that may have been protected for them.
Taken in this context, the notion of protecting “ecologically significant areas”, as is stated in many planning policies, is unsound. Almost any area in an environment is likely to be significant. If it supplies a need for some species, it can not stand alone. Various other areas, or habitat patches, also will be required. But patches in a mosaic that don’t fill a need easily could be ecologically significant by acting as a hazard or barrier to movement of species among the patches that do fill a need. Highways and subdivisions are easy examples. The notion of “significant areas” is just as weak as the notion of “significant species” when taken without the context of function in the natural processes of the ecosystem.