Effect of environmental conditions on species composition of macrophytes – study from two distinct biogeographical regions of Central Europe

The relationship between macrophytes and environmental conditions of lotic and lentic habitats was studied within two distinct biogeographical regions (Pannonian and Carpathian) represented by two model areas (Borská nížina lowland and Turčianska kotlina basin) in 2011. Altogether, 72 taxa of macrophytes were found within both studied biogeographical regions, while almost a third of them grew only in one from the regions. Species-environmental variables relationship was studied by Canonical Correspondence Analysis (forward selection), which revealed that three and seven environmental variables explaining 10.35% and 24.45% of variance of species data had significant effect on species composition of macrophytes in the Pannonian and Carpathian region, respectively. Flow regime and the portion of fine substrate on the bottom are the main drivers of species composition-environmental condition relationships and explained 3.57% and 6.21% of variance in the Pannonian and Carpathian region, respectively. However, the highest values of pure effect on species composition was detected in case of Altitude (Pannonian region; 3.81%) and Connectivity (Carpathian region; 3.19). Based on the variation partitioning, landscape variables (including geographical variables; Pannonian region; 6.8%) and hydrological variables (including morphological variables of the bottom; Carpathian region; 11.3%) explained a bigger portion of the variability of macrophytes in regions than the other groups of environmental variables. La relation entre les macrophytes et les conditions environnementales des habitats lotiques et lentiques a été étudiée dans deux régions biogéographiques distinctes (Pannonie et Carpates) représentées par deux zones modèles (la plaine Borská Nizina et le bassin kotlina Turčianska) en 2011. Au total, 72 taxons de macrophytes ont été trouvés dans les deux régions biogéographiques étudiées, tandis que près d’un tiers d’entre eux ne pousse que dans une seule des régions. La relation des variables espèce-environnement a été étudiée par analyse canonique des correspondances, qui a révélé que trois et sept variables environnementales expliquant 10,35 % et 24,45 % de la variance des données sur les espèces ont un effet significatif sur la composition des espèces de macrophytes dans les régions de Pannonie et des Carpates, respectivement. Le régime hydrologique et la portion de substrat fin sur le fond sont les principaux moteurs des relations environnement-composition spéc