Effect of environment on distributions of rock ferns in the Mediterranean climate: The case of the genus Asplenium in Montenegro

The aim of this study was to explore the way in which environmental aspects influence distributions of rock flora of the Mediterranean basin, using the genus Asplenium as a study system. Using the most comprehensive dataset to date built with the data from museum collections and those obtained in the course of a field survey, we identified patterns of species richness, carried out multivariate analysis, and fitted generalised linear models to the presence/pseudo-absence and abundance data of the three wide-spread taxa. We complemented the information on climatic preferences of the Asplenium ferns by phytosociological data. Based on their distributions in the ecological space defined by temperature- and precipitation-related variables, the Asplenium ferns known for Montenegro were assigned to the three groups: coastal species, generalist, and highland species. Within these groups, no further niche differentiation could be detected given the available environmental factors. Phytosociological information from herbarium specimens was consistent with the results of the multivariate ecological analysis. Non-climatic environmental factors were limiting the distributions of the Asplenium ferns on the country-size scale, but were not statistically significant in separating niches among the species. Our results showed a significant impact of water deficit on the distributions of the two morphologically distinct and locally abundant species; these species can be recommended as potential indicators of the increasing water deficit stress in the European Mediterranean climate. Species richness patterns of the spleenworts of Montenegro suggested that the whole country was important for maintaining the diversity of this group of plants. This study demonstrates the value of natural history collections combined with field data to inform ecological research. For the first time, a numerical analysis of the data concerning distribution and abundance of the most common and wide-spread European ferns of the genus Asplenium in an area with the typical Mediterranean climate was carried out. (C) 2015 Elsevier GmbH. All rights reserved.