Environmental, Spatial and Structural Components in the Composition of Mountain Forest in the Bavarian Alps

• Published in: Folia geobotanica Vol. 49; no. 3; pp. 361 - 384
• Main Authors: Fischer, Hagen S., Michler, Barbara, Ewald, Jörg
• Format: Journal Article
• Language: English
• Published: Dordrecht Institute of Botany, Academy of Sciences of the Czech Republic 01.09.2014; Springer Netherlands
• Subjects: Biomedical and Life Sciences; Climate models; Coniferous forests; Datasets; Forest soils; Life Sciences; Montane forests; Ordination; Plant Ecology; Plant Sciences; Plant Systematics/Taxonomy/Biogeography; Soil composition; Statistical variance; Understory; Vegetation; Forest management; Species composition; Constrained ordination; Environmental gradients; Variance partitioning; Bavarian Alps
• ISSN: 1211-9520; 1874-9348
• DOI: 10.1007/s12224-013-9185-x

A combined systematic and stratified sampling design was conducted in mountain forests of the Bavarian Alps to find the principal dimensions of compositional variation of vegetation and their environmental drivers. In 1,505 plots species composition, forest types and soil profiles were recorded. Data from 14 climate stations were included. As we hypothesized that the tree layer is more influenced by management than the understorey and that the former modifies the habitat of the latter, the two matrices were analysed separately and the species composition of the tree layer was used as a structural predictor variable for the understorey. We applied constrained ordination to reveal the main gradients in floristic composition and variance partitioning to examine the portions of climatic, edaphic, spatial and structural components. Ellenberg indicator values and a generalized linear model were used to test whether a significant spatial gradient exists from east to west, the main spatial extent of the investigation area. Forest types were used as an overlay to assess the underlying environmental factors. It turned out that explained variance of the tree layer was considerably lower than in the understorey. Tree layer composition was more influenced by climatic variables than by soil. In the understorey, edaphic and climatic variables contributed almost equally to explained variance, but the tree layer had an additional explanatory power. No continentality gradient could be detected within the investigation area. Plant communities were well separated along gradients of acidity, moisture, nutrients and climate, which broadly confirms the known gradients for montane and subalpine zonal forests in the region. The study provides a quantitative synthesis of the knowledge on a diverse set of community types, which has so far been subject to disparate and sectorial treatment in the Bavarian Alps.