Zoran Markovic

DISTRIBUTION OF THE SPECIES GAMMARUS BALCANICUS AND GAMMARUS FOSSARUM ON THE TERRITORY OF SERBIA (CENTRAL PART OF THE BALKAN PENINSULA)

[The results presented in this paper point to the need for a revision of the known distribution areas of the species Gammarus balcanicus and Gammarus fossarum, as well as of their contact zones, both on the territory of Serbia and on the Balkan peninsula as a whole.The occurrence of G. fossarum in western Serbia contradicts the assertion that G. balcanicus is the best represented species of this genus in western Serbia and indicates a considerably wider range for G. fossarum.The results presented herein undermine the previously held belief that G. fossarum is only sporadically encountered in Serbia (especially in southern and southeastern Serbia) and indicate that it is the most abundant and most frequently found species in the catchment area of the Southern Morava (southeast Serbia). Moreover, mixed populations of these two amphipods are encountered at the majority of the localities in the Southern Morava.It is here established that the zone of contact between G. balcanicus and G. fossarum is considerably wider than was imagined and in reality stretches into southern and southeastern Serbia: it was previously thought that the contact zone lies between the rivers Morava and Drina in western Serbia and on Mt. Kopaonik in central Serbia. Since G. fossarum is dominant in relation to G. balcanicus in the given region, it can be expected that future finds will further extend the zone of contact between these two vicariant forms to the south and southeast of the Balkan Peninsula. Les resultats presentes dans ce travail indiquent la necessite de reviser les aires de repartition connues des especes Gammarus balcanicus et Gammarus fossarum, ainsi que leurs zones de contact, a la fois sur le territoire de Serbie et sur la peninsule des Balkans dans son ensemble.La presence de G. fossarum en Serbie occidentale contredit lassertion suivant laquelle G. balcanicus est lespece de ce genre la plus representee en Serbie occidentale et indique une aire considerablement plus vaste pour G. fossarum.Les resultats presentes ici remettent en cause la croyance suivant laquelle G. fossar um se rencontrait seulement sporadiquement en Serbie (en particulier dans le sud et le sud-est de la Serbie) et indiquent que cest lespece la plus abondante et la plus frequemment trouvee dans les eaux de Moravie meridionale (Serbie sud-orientale). De plus, des populations mixtes de ces deux amphipodes sont presentes dans la majorite des localites de la Moravie meridionale.Il est etabli ici que la zone de contact entre G. balcanicus et G. fossarum est considerablement plus large quon ne limaginait et en realite, elle setend jusquen Serbie du sud et du sud-est: on pensait auparavant que la zone de contact se situait entre les rivieres Morava et Drina en Serbie occidentale et sur le mont Kopaonik en Serbie centrale. Etant donne que G. fossarum est dominant par rapport a G. balcanicus dans cette region, on peut sattendre a ce que des trouvailles futures etendent la zone de contact entre ces deux formes vicariantes vers le sud et le sud-est de la peninsule des Balkans., The results presented in this paper point to the need for a revision of the known distribution areas of the species Gammarus balcanicus and Gammarus fossarum, as well as of their contact zones, both on the territory of Serbia and on the Balkan peninsula as a whole.The occurrence of G. fossarum in western Serbia contradicts the assertion that G. balcanicus is the best represented species of this genus in western Serbia and indicates a considerably wider range for G. fossarum.The results presented herein undermine the previously held belief that G. fossarum is only sporadically encountered in Serbia (especially in southern and southeastern Serbia) and indicate that it is the most abundant and most frequently found species in the catchment area of the Southern Morava (southeast Serbia). Moreover, mixed populations of these two amphipods are encountered at the majority of the localities in the Southern Morava.It is here established that the zone of contact between G. balcanicus and G. fossarum is considerably wider than was imagined and in reality stretches into southern and southeastern Serbia: it was previously thought that the contact zone lies between the rivers Morava and Drina in western Serbia and on Mt. Kopaonik in central Serbia. Since G. fossarum is dominant in relation to G. balcanicus in the given region, it can be expected that future finds will further extend the zone of contact between these two vicariant forms to the south and southeast of the Balkan Peninsula. Les resultats presentes dans ce travail indiquent la necessite de reviser les aires de repartition connues des especes Gammarus balcanicus et Gammarus fossarum, ainsi que leurs zones de contact, a la fois sur le territoire de Serbie et sur la peninsule des Balkans dans son ensemble.La presence de G. fossarum en Serbie occidentale contredit lassertion suivant laquelle G. balcanicus est lespece de ce genre la plus representee en Serbie occidentale et indique une aire considerablement plus vaste pour G. fossarum.Les resultats presentes ici remettent en cause la croyance suivant laquelle G. fossar um se rencontrait seulement sporadiquement en Serbie (en particulier dans le sud et le sud-est de la Serbie) et indiquent que cest lespece la plus abondante et la plus frequemment trouvee dans les eaux de Moravie meridionale (Serbie sud-orientale). De plus, des populations mixtes de ces deux amphipodes sont presentes dans la majorite des localites de la Moravie meridionale.Il est etabli ici que la zone de contact entre G. balcanicus et G. fossarum est considerablement plus large quon ne limaginait et en realite, elle setend jusquen Serbie du sud et du sud-est: on pensait auparavant que la zone de contact se situait entre les rivieres Morava et Drina en Serbie occidentale et sur le mont Kopaonik en Serbie centrale. Etant donne que G. fossarum est dominant par rapport a G. balcanicus dans cette region, on peut sattendre a ce que des trouvailles futures etendent la zone de contact entre ces deux formes vicariantes vers le sud et le sud-est de la peninsule des Balkans.]