Fragmentation causes local extinction of species within local populations. Therefore measurements to be taken in order to maintain or regain species in a fragmentated landscape or region should deminish the chances for extinction or increase the chances for recolonization. Such measurement are the improvement and enlargement of the habitats of local populations and the making of connections between local populations. Environmental Heterogeneity and diversity Two or more divergent phenotypes in an environment may be favoured simultaneously by diversifying selection. This is called environmental heterogeneity .
Species cope with environmental heterogeneity in diverse ways.
One strategy is the selection of a generalist genotype that is well adapted to all of the subenvironments encountered by the species. Another strategy is genetic polymorphism, the selection of a diversified gene pool that yields different genotypes, each adapted to a specific subenvironment. There is no single plan that prevails in nature. Sometimes the most efficient strategy is genetic monomorphism to confront temporal heterogeneity but polymorphism to confront spatial heterogeneity. If the environment changes in time, if it is unstable relative to the life span of the organisms, each individual will have to face diverse environments appearing one after the other.