Orchids of Russia and Crimea: herbarium collections provide sufficient data to recover the distributional changes with time

Abstract

Monitoring the distributional changes of native vascular plants over time is an important task both from the scientific and conservation point. However, numerical data for such studies are often missing, especially for countries lacking national biodiversity datasets, such as Russia. The main aim of this study was to assess whether direct data from herbarium collections are sufficient to recover the distributional changes effectively. The object of this study was the orchid family, a conservationally important group of plants, in the Flora of Russia and Crimea. Primary source of the data were georeferenced herbarium labels from 59 herbarium collections. The distributional changes were assessed by comparisons between the numbers of grid cells with records in different time intervals, taking into account the variation of recording intensity with time.The method proved to be applicable to 108 out of 135 species of orchids occurring within the studied territory. For many of them, reliable changes in the number of localities were confirmed. Among widely distributed orchid species constant negative change was detected for Anacamptis coriophora, Calypso bulbosa, Coeloglossum viride, Cypripedium guttatum, C. macranthos, Gymnadenia conopsea, Herminium monorchis, Neotinea ustulata, Orchis militaris, Platanthera hologlottis; constant positive change was recovered for Dactylorhiza baltica and D. fuchsii only. In many species, trends over time were uneven. The direction of change proved to be generally consistent for a given species across the whole studied territory, suggesting the principal influence of general factors, such as climate change and general eutrophication of the environment. The direction of change is consistent with type of geographic distribution of plants.Although the method used in the current study for recovering distributional changes has limitations, it may be further recommended for use with other taxa.