Dynamics of community patches and ecotypes in the agricultural landscapes

Abstract

Every land reform deals with changes of landscape structure. Current Lithuanian agricultural landscape was predetermined by water abundance in the soil and by extensive agriculture. During the process of reclamation and regulation of water regime the soil and expansion of aerable land areas of natural communities was drastically transformed into farming lands. In new transformed fields there is less than 10% of former natural communities areas. Depending on the transformation, fields relief and soil moisture loses considerable amount of communities, plant and animal species. In the process of these changes of agricultural landscape, the biological diversity is physically destroyed. Only big and adult wertebrals migrating to new natural community areas can avoid physical demolition. But the natural communities which untransformed experience stress: a) the level of the soil water is reduced, b) the ecotype changes, c) disbalance between autotrophs and heterotrophs is violated. For of ail these reasons the structure of natural communities is disturbed the anthropogenical succession takes place. Species structure changes basically. In the agrocultural landscape cultural, adventual plants' and animals' species are predominating. In order to reconstruct violated equilibrity in the agricultural landscape we must project new renaturalaised areas.