Conservation of marginal areas in protected territories: The Ojcow National Park - Case study

Abundant literature concerned with flora and fauna of the Ojcow National Park (ONP) allowed to reconstruct changes occurring there during the last 150 years. Human activity in the area increased the number and diversity of ecosystems (plant communities). Taking of that site under protection resulted in a decrease in spatial differentiation and number of ecosystems, mainly semi-natural chalk grasslands and semi-open bushy habitats. This have caused great changes in flora and fauna. A marked decrease in the number of species confined to water-marshy and xerothermic habitats and a slight decrease in shade-loving and oligothermic species are observed. Only meadow and pasture species increased in number during the last 150 years. Landscape and environmental changes occurring around and within the ONP lead to increasing isolation of local nature and growing rate of autochtonous species extinction. As the rate of species immigration to the Park can not be influenced the authors decided that conservation work should be focused on decreasing the rate of species extinction in the area. The authors' proposals are: to maintain a considerable diversity of ecosystems in the Park, with special regard to semi-natural ecosystems to create and maintain local source habitats supporting source populations to create 'species packing' corridors to create 'walking sources' for chalk grassland ecosystem species within corridors.