Ecological conditions of the vegetation and vascular plant species distribution in the selected forest seepage spring area (NE Poland) based on a fine-scale assessment

Abstract

The existence and functioning of spring ecosystems is determined by groundwater seepage or outflow. The water seeping through the ground surface triggers off the headward and deep erosion processes, which results in the channelled shape of the lowland rheocrenic springs. Spring areas significantly contribute to the floristic, phytocoenotic and landscape diversity. The literature on the vegetation cover of lowland spring ecosystems is scarce. Most papers refer to the identification of their flora and plant communities, less frequently – the relationships between habitat conditions and vegetation. The studies indicate that pH and moisture content are the main factors determining the composition and species diversity of ecosystems supplied by groundwater. My study presents a detailed geobotanical analysis performed on one forested spring area (together with an adjacent area) of 0.378 ha, which was divided into 945 study plots – squares with an area of 4 m2. Three zones were distinguished in the studied spring area: the bottom with a specific mosaic pattern caused by the presence of streams, water seepage sites and mineral islands, the steep slope and the surrounding area. A detailed map of habitats and the actual vegetation was prepared. A list of vascular plant species was compiled for each study plot, based on which maps with the distribution of mean Ellenberg’s indicator values were created. Statistically significant differences in the variance of Ellenberg’s indicator values between the distinguished zones were demonstrated (ANOVA), and the correlations between the ecological indicators within a given zone were calculated. CCA analysis of plant communities and the distinguished zones revealed that the occurrence of e.g. Carici remotae-Fraxinetum and non-forest plant communities of wet and moist habitats is associated with the bottom of the niche characterised by a high value of Ellenberg’s moisture indicator F. Whereas the Acer platanoides-Tilia cordata community and the Tilio-Carpinetum corydaletosum association develop on the slope with high values of the temperature indicator T. Furthermore, the CCA analysis performed on the plant species and the distinguished zones confirmed the above results. It has been shown that the species composition and the distribution of plant species and plant communities in the study area are mainly determined by soil moisture content, but also by light and temperature.