Relief and changes in the vegetation cover and the flora of the Zadroże Dune near the city of Toruń: Comparison of the conditions in 1948 and 2009

Abstract

The relief of the Zadroże Dune was described, as well as the comparison was done on its vegetation cover and the flora in its two phases of the development, i.e. before the afforestation of the dune and approximately 60 years after reconstruction of the forest. The first state was described in the paper dated 1949. During that period the dune constituted the first common study area for the research team consisting of ecologists and geographers from the Nicolaus Copernicus University. Our contemporary scientific studies were carried out in 2009. In the comparative analysis, a particular attention was paid to the distribution, the number and the size of heath patches with Arctostaphylos uva-ursi. In the description of the contemporary state of vegetation, the structure and the biomass of tree stands were included. The GIS and GPS technologies were applied in the comparative analysis of the vegetation, in the comparison of the former and contemporary cartographic materials, aerial and satellite images, as well as in the development of a digital elevation model. As a result of comparisons of the vegetation cover, it was found that the surface area of heaths decreased from 59.21 ares in 1948 to 2.96 ares in 2009. As a result of comparisons of the flora, it was found that 7 and 26 species of lichens occurred in 1948 and 2009 respectively, 5 and 42 species of mosses, 0 and 7 species of liverworts, as well as 102 and 204 species of vascular plants. The number of families, within which the species of vascular plants are classified, increased from 31 to 52. The compared floras have only 66 species in common. The percentage contribution of geographical and historical groups has undergone only inconsiderable changes during the 60-year period. Contribution proportions of non-synanthropic spontaneophytes and apophytes has changed slightly. Whereas, the contribution of alien species, mainly kenophytes and ergasiophytes significantly increased. This paper discuss the significance of natural and anthropogenic factors, which brought about this considerable range of transformations in the species composition and in the contribution of alien species.