Topographic attributes and ecological indicator values in assessing the ground-floor vegetation patterns

The paper discusses the question whether geographical information systems (GIS) and digital elevation models (DEM) are useful tools for studying correlations between topographic attributes of a given area, and vascular flora requirements reflected by ecological indicator values (EIVs). The model object was a 4-km-long gorge section of the Sopot river valley (80.5 ha), the Central Roztocze Highlands, South-East Poland. Species lists for 40 ca. 200-m-long and 100-350-m-wide sections, according to the river course, separately for the left and right riverbanks, were made. The analysis of the area was based on a 3-meter resolution DEM. We applied primary topographic attributes: slope, and planar, vertical, and total curvatures and also secondary topographic attributes: solar radiation (SRAD) and topographic wetness index (TWI), as well as other terrain characters: denivelation, total, flat and upslope area of each section. Using the multivariate analyses, we analysed relationships between weighted averages of EIVs for each species and topographic attributes.

The GIS and DEM became useful tools for the detection of patterns of species with different habitat requirements. The species number correlated positively with the total and flat area of a section and the TWI, while the denivelation, mean slope and upslope area had a reverse vector. Among the most frequent and abundant herb species, we found several spatial patterns of distribution, namely those of: Maianthemum bifolium, Carex remota, C. acutiformis, Filipendula ulmaria, Dryopteris filixmas, and Urtica dioica. The rarest species represented Ajuga genevensis, Scorzonera humilis, and Stachys palustris patterns.