Early successional pathways in the Tatra Mountains (Slovakia) forest ecosystems following natural disturbances

Large scale windstorms disturbed forest ecosystems in the Tatra Mountains in 2004, and were followed by a severe fire in 2005. A long-term study on the vegetation successional dynamics of the area was launched immediately after the 2005 event. Relevé plots were established under five different disturbance and management treatments: windthrow left, windthrow removed, hydrologically managed, burnt and reference. We used weighted Ellenberg’s indicator plant values for ordination analyses of the following environmental gradients: light, temperature, continentality, moisture, acidity, nitrogen. Successional patterns depended on the management treatment. Heavily burnt areas were colonized by plants disseminated by airborn diasporas, mainly by Chamaerion angustifolium , less burnt or unburnt localities were settled by plants germinating from the soil seed bank or by plants surviving by root system. Nitrophilous weed vegetation invaded plots with increased moisture (fallen or standing overstory vegetation or irrigated by man-made system) and nitrogen (burnt or windthrow removal). The felled-area species were recorded in each plot. Abundant natural regeneration was observed in plots with increased moisture. The moss layer disappeared soon after the disturbance events. The results presented here refer to a very early successional stage, new insights into initial successional paterns are gained.