Bryophyte responses to a moisture gradient within two different spatial scales in mown meadows and mesic pastures

Abstract

Soil moisture is one of the most important environmental factors that affects species composition patterns in herbaceous plant communities. Changes in bryophyte cover along moisture gradient were recorded at two spatial scales in the vegetation of mown meadows and mesic pastures (Molinio‐Arrhenatheretea class). The Slovak national dataset (SK) of 1183 vegetation plots and a local subset of 160 plots on the Muránska planina Mts (MP) were analyzed. The main compositional gradient was determined by detrended correspondence analysis and was interpreted using Ellenberg indicator values for vascular plants. Variations in species composition in both datasets were similarly driven by moisture. The most common bryophytes at the national and local scales were the pleurocarpous mosses Brachythecium rutabulum (Hedw.) Schimp., Calliergonella cuspidata (Hedw.) Loeske, Climacium dendroides (Hedw.) F. Weber & D. Mohr, Plagiomnium affine agg. (Blandow ex Funck) T. J. Kop. and Rhytidiadelphus squarrosus (Hedw.) Warnst. A general linear model using bryophyte cover as a dependent variable was significant for all five taxa in the SK dataset and for four taxa in the MP dataset (except for C. dendroides). The highest explained variation was found for C. cuspidata (8.4% SK; 7.1% MP), R. squarrosus (7.2% SK; 12.5% MP) and P. affine agg. (4.6% SK; 23.2% MP). The shape of the bryophyte cover‐moisture relationship was analyzed for all five mosses using only plots in which they were present. Regression analysis was significant for two mosses at both spatial scales; a monotonic negative trend was found for R. squarrosus and a positive trend for P. affine agg.