The conservation challenge of sustaining spatially dependent evolution

Maintaining evolutionary processes is a fundamental tenet of biodiversity conservation. Dispersal in the guise of range expansion may take place over many generations and is a key evolutionary process. Range expansion enables evolutionarily novel gene combinations in single populations to become widespread taxonomic units, it enables homogeneous populations to reach refuges which may later become isolated and diverge, and range expansion may enable species to track their environmental niche as climates change. Land management practices that impede permeability also inhibit range expansion. Land clearing, grazing, inappropriate fire regimes and introduced species have the potential to block dispersal, preventing range expansion and eliminating spatially-dependent evolutionary processes. To achieve the goal of maintaining natural processes of evolution. landscape permeability needs to be understood and re-established in the many places where it has likely been lost.