In an ideal world, the environmental conditions that ecosystems require in order to function, would be provided by conserving natural areas that are large enough to accommodate entire ecosystems. But this is often difficult to achieve in practice because of the pressures on the environment caused by economic development and other human activities. The challenge in the real world is therefore to find ways in which ecosystems can continue to function in landscapes that are also used for human activities. Ecological networks meet this challenge because they provide an operational model for conserving biodiversity that is based on ecological principles yet still allows a degree of human exploitation of the landcape.
In order to meet the needs of ecosystems, three broad guidelines for conservation action can be applied: a) the entire range of habitat types should be conserved in areas which in principle are as large and as numerous as possible and extend across their entire natural range; b) where it is only feasible to conserve habitats as a collection of several smaller areas, the areas should be as close together as possible and physically interconnected as appropriate in order to allow the dispersal and migration of species and genetic exchange between different local populations; and c) where necessary, the quality of the environment within the areas should be protected from the damaging effects of activities outside the areas. These guidelines have led to the development of a practical model for the conservation of biodiversity: the ecological network.
One of the most important means through which the Pan-European biological and Landscapes Diversity Strategy is being implemented is the establishment of the Pan-European Ecological Network. The participating states have agreed that the network should be established by 2005. The formulation of the criteria and methods for developing the Pan-European Ecological Network and the selection of the ecosystems, habitat types, species and landscapes of European importance are being coordinated by the European Centre for Nature Conservation in association with other programmes such as the development of a European Coastal and Marine Ecological Network and WWF's Large Carnivore Initiative.