Anna Kowalska

Abstract This paper has sought to point to past-present differences in the nature and spatial distribution of plant communities, as well as to determine the general directions to the environmental transformations taking place along the Middle Vistula Valley. The research has concerned the 50-year period 1949-2001, with changes registered cartographically. At the landscape level, vegetation together with relief, water and soil conditions is a major deciding factor where the shaping of the environment is concerned. Vegetation offers direct indication as regards present-day landscape structure, as well as the most sensitive indication of both system dynamics and changes in the landscape, be these either natural or anthropogenic. Modifications of vegetation usually represent the first signs of environmental change. For these reasons, a knowledge and understanding of the factors and processes leading to the present state of vegetation provide for a determination of the potential effects of planned activities, and their influence on the natural environment. Over 35% of the area was found to have experienced changes in vegetation, though these changes varied in character and intensity from one part of the valley to another. Above all, however, the results of the analysis reflected changes in practices as regards agricultural land-use, this being particularly visible in the way that the area of segetal communities has declined markedly, in the wake of increases in the area of grassland, forest and scrub. Grassland communities themselves manifested two opposing directions to changes: on the one hand an intensification of meadow and pastures use leading to the decline or even disappearance of extensively-used meadows, and on the other the overgrowth of many abandoned grasslands by shrubs and trees. Similar processes have in fact been observed in other parts of Poland too (Herbich, 1994; Kucharski, 1999, 2000). Further detected changes in plant communities are indicative of a lowering of the water level or a change in the horizontal movement of water. The processes ongoing entail an evolution from communities with a high (or fluctuating) water level, often with stagnant water (e.g. Carex meadows, Molinia meadows and alder carr) to those characteristic of less moist habitats or those with running water (Arrhenatherum or Caltha meadows, ash-alder forests and ultimately oak-lime-hornbeam forest). This type of change has mostly been brought about by agricultural drainage. Other important processes observed in the valley as a whole entailed changes in aquatic habitats leading to the aggradation and overgrowth of river-channels and bodies of water. Indeed, the area encompassed by waters actually decreased by more than 32% during the study period. Aggradation of river-beds resulted from current concentration (via hydro-engineering construction) and the intensified accumulation of sediment. Overgrowth in bodies of water (mainly ox-bow lakes) in turn reflected embankment construction limiting the influence of flooding. There was a general increase in anthropisation of the landscape, though in some parts of the valley (e.g. the Wilga area) it was restoration processes that dominated - mainly due to land-cover changes, but also to modifications in plant communities that did not change their overall character (in that land-use forms remained the same), but did lead to changes as regards both structure and biodiversity. These changes above all involved the evolution of meadows into other grassland types subject to more intensive use, or else processes of degeneration in forests. The increasing anthropisation of vegetation was also a product of increases in the areas covered by ruderal vegetation or orchards.

Keywords: Dolina Środkowej Wisły, analiza historyczna, zmiany roślinności, użytkowanie ziemi, numeryczne mapy roślinności

Anna Kowalska [aniak@twarda.pan.pl], Institute of Geography and Spatial Organization Polish Academy of Sciences, Twarda 51/55, 00‑818 Warszawa, Poland

Citation

APA: Kowalska, A. (2009). Zmiany charakteru i rozmieszczenia zbiorowisk roślinnych w dolinie środkowej Wisły w drugiej połowie XX wieku (odcinek Annopol–Góra Kalwaria). Przegląd Geograficzny, 81(3), 347-364. https://doi.org/10.7163/PrzG.2009.3.2
MLA: Kowalska, Anna. "Zmiany charakteru i rozmieszczenia zbiorowisk roślinnych w dolinie środkowej Wisły w drugiej połowie XX wieku (odcinek Annopol–Góra Kalwaria)". Przegląd Geograficzny, vol. 81, no. 3, 2009, pp. 347-364. https://doi.org/10.7163/PrzG.2009.3.2
Chicago: Kowalska, Anna. "Zmiany charakteru i rozmieszczenia zbiorowisk roślinnych w dolinie środkowej Wisły w drugiej połowie XX wieku (odcinek Annopol–Góra Kalwaria)". Przegląd Geograficzny 81, no. 3 (2009): 347-364. https://doi.org/10.7163/PrzG.2009.3.2
Harvard: Kowalska, A. 2009. "Zmiany charakteru i rozmieszczenia zbiorowisk roślinnych w dolinie środkowej Wisły w drugiej połowie XX wieku (odcinek Annopol–Góra Kalwaria)". Przegląd Geograficzny, vol. 81, no. 3, pp. 347-364. https://doi.org/10.7163/PrzG.2009.3.2