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ŠUMARSKI LIST 3-4/2020 str. 29     <-- 29 -->        PDF

Morfometrijska i morfološka analiza lista crne topole (Populus nigra L.) u plavnim i neplavnim područjima sliva Dunava
Morphometric and morphological analysis of Populus nigra L. leaves in flooded regions
Danijela Miljković, Dijana Čortan
Human activity induced global changes in nature, particularly the flooding regime, which is a stress factor affecting wetland ecosystems. Knowledge of plant strategies of wetland vegetation across a range of flooding gradients is therefore very important. Natural flooding events are increasing as a consequence of constant climate changes. This research was focused on the area of Special Nature Reserve “Gornje Podunavlje” which represents a complex of peculiar marshland, originating from former vast inundated parts of the Danube basin. We have selected samples located on both sides of the embankment in the defended and in the flooded area. The main aim is the assessment of Populus nigra L. riparian tree leaf morphological traits variability (centroid size, shape, developmental instability, specific leaf area and petiole lenght) between two habitats (flooded and not flooded). The geometric morphometry methods were applied to provide visual representation of differences in the leaf shape. We employed leaf composite index indices of fluctuating asymetry as a measure of developmental instability. A statistically ­significant impact of flooding was obtained only for the leaf geometric size and shape, so these traits could be an indicator of flooding as suboptimal environmental conditions.
Key words: riparian tree species, Populus nigra L., leaf developmental instability, leaf shape, flooding tolerant, Danube basin.
The management of river flows has altered flooding patterns and reduced their frequency and duration in many European floodplains (Hughes et al., 2000). Riparian tree species are heavily dependent on the floods, both for providing new sites for their natural regeneration from seed and as well as for recharging water table levels in the rooting zone. These species may tolerate weeks and even months of flooding, however Populus nigra L. cannot withstand flooding longer than 60 days (Herpka, 1963). A decrease in the number of floods has led to loss of the natural corridor that facilitates gene flow for many riparian species (Storme et al., 2004), with early successional riparian tree species being particularly adversely affected (Hughes et al., 2000). River damming and water diversion, by reducing the opportunities for regeneration of these pioneer species, contributed to the collapse of riparian pioneer populations along many river valleys, which threatens the stability of this vulnerable