Our goal is to explore spatio-temporal patterns in forest plant species and communities at various scales. The target area is Moravia – the eastern part of the Czech Repubic. The study period is the past 70-80 years as far as field data sampling is concerned, and the past ten thousand years regarding indirect evidence and cooperation with other disciplines in the project.
Various aspects of diversity of plant species and their communities are related to important environmental factors. The focus is on herb layer species and site conditions, such as soil chemistry, management intensity, structure of woody overstory and light availability. The diversity of the herb layer can vary from zero to one hundred of species in an area of 400 m2 (the typical size of sampling plots), whereas tree species diversity reaches much lower values (up to 5-10 species per plot).
The principal data source is vegetation plots. Samples available from species-plot databases are combined with environmental data sources such as climate, soil, geology etc. This information is compared with spatially relevant palaeoecological and historical data in order to reveal historical analogues of recent vegetation.
On a regional scale, the main approach is the resampling of vegetation plots from the 1940s to the 1960s. Resampling is an effective tool to study vegetation and environmental changes in forests during the 20th century, a period marked by profound changes in forest management and environmental impacts, such as nitrogen deposition and climatic warming. Our work is based on a dataset of several hundred resurveyed plots from a number of regions collected in lowland forests. Plots at higher elevated areas enable us to understand processes along the main natural gradient in the study area, i.e. from lowland to mountainous forests.
The other main approach uses permanently fixed plots. The sampling methodology is similar to the resampling of historical plots. The difference is in the intensity of temporal coverage and the precision of vegetation and environmental data. Data on soil chemistry, light availability and tree species composition are systematically sampled. The project benefits from over four hundred standardized permanent plots that our research team established in lowland forests in 2008-2013. As an extension, detailed information on woody layer structure, forest interior temperature and nitrogen mineralization under different management regimes are continuously monitored.