engleski

Morphological variability of invasive macrophyte Elodea nuttallii (Planch.) H.St.John along habitat and species composition gradients

In period 2006-2009, the linear spreading of invasive macrophyte Elodea nuttallii was noted along the drainage channel system of Baranja (Croatia). To determine the morphological variability of invasive E.nuttallii in relation to habitat characteristics and species composition during its invasion phase, sites were monitored in a three year period with sampling in summer 2007 and spring and summer in 2008 and 2009. Multiple factor analysis shows that morphological variability of E.nuttallii is mostly linked to the species composition and partly to habitat conditions. In shallow waters, with free-floating vegetation and higher concentrations of nutrients, E. nuttallii had narrower and longer leaves and internodes and in deeper water, with submerged vegetation and lower concentrations of nutrients, it had broader and shorter leaves and internodes. The high morphological variability allows E. nuttallii to survive and establish in different environmental conditions and increases the potential of spreading in favourable conditions. Even in highly unfavourable conditions in free-floating vegetation, high morphological variability enables the survival of E. nuttallii. In our research the resistence of the ecosystem through the native macrophyte composition is highlighted as the main factor in decreasing impact of the invasive species.

morphological variability; invasive macrophyte; Elodea nuttallii; habitat gradient; species composition gradient

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