Indicating Soil Acidity Using Vegetation Relevés in Spatially Limited Areas – Case Study from the Považský Inovec, Slovakia

Abstract

A fine-scaled approach for predicting soil acidity using plant species in a spatially limited area (Čepúšky Nature Reserve, Slovakia) is presented here. This approach copes with some specific limitations: i) a limited pool of vegetation data may make the predictions too sensitive to the lack of species information, and ii) the predictions may be sensitive to the narrow pH gradient. Vegetation relevés and soil reaction (pH-H 2 O and pH-CaCl 2 ) were systematically recorded. A set of species indicator values and amplitudes was calibrated with physical pH data using the Weighted Averaging (WA), HOF modelling and Non-Metric Multidimensional Scaling (NMDS) methods, along with Ellenberg indicator values. Two prediction methods were tested: i) WA and ii) Amplitude Overlap (AO). WA prediction with Ellenberg's and WA-calibrated species indicator values were the most powerful technique (R 2 =68.4-68.7% and 53.4-59.1% for pH-CaCl 2 and pH-H 2 O, respectively). WA-prediction with HOF-based indicator values was less effective (R 2 =61.7% and 50.7%) due to the decrease in species' information because with HOF modelling many species are assumed indifferent or too rare. The NMDS method does not bring any significant gain to the calibration, though it avoids the lack of species information. The AO method was proven to be less powerful under studied circumstances, because it is sensitive both to the lack of species' information and to the truncation of species responses. The results prove that a spatially explicit approach can provide significant indices to estimate changes in soil acidity -pHCaCl 2 better than pH-H 2 O.

Experience with using Ellenberg’s R indicator values in Slovakia: Oligotrophic and mesotrophic submontane broad-leaved forests

“…ad hoc optima and tolerances. As shown by Balkovič et al (2010), the WA prediction method is quite resilient to this limitation. It is also resilient to initial assumptions about evenly distributed IVs.…”

“…Species with type I curve were considered indifferent. The R h value is defined as the pH scale value where the area under the curve reaches half its maximum (Balkovič et al 2010). Species tolerance (T h ) was defined as the interval where the area under the curve contains 80% probability of species occurrence (Gégout & Pierrat 1998).…”

Changes of forest abiotic environment in the Western Carpathians assessed using phytoindication

“…A particular approach to environmental monitoring that does not rely on specialist equipment and expensive analyses (Diekmann 2003) and which makes it possible to obtain data with high spatial resolution (Balkovič et al 2010) is to use phytoindication. Under this approach repeated sampling of phytosociological permanent plots is performed, and observed shifts in the vegetation composition are interpreted in terms of environmental change by referring to the changes of average Ellenberg's Indicator Values (AIVs).…”