ABSTRACT
The Orchidaceae, which is one of the most interesting families of angiosperms, contains a large number of rare species. Despite their acknowledged importance, little attention has been paid to the study of orchids distributed in northern territories. In this study, we determined the syntaxonomical diversity and ecological parameters of orchid habitats in two of Europe's largest protected areas, the Pechoro-Ilychsky Reserve and the Yugyd Va National Park (northeastern European Russia), and then compared our findings to those in other parts of orchid distribution ranges. For this purpose, we studied 345 descriptions of plant communities (releves) containing species from Orchidaceae and defined habitat parameters using Ellenberg indicator values with the community weight mean approach, nonmetric multidimensional scaling (NMS), and relative niche width. We found that orchids were distributed in eight habitat types and 97 plant associations. The largest number of orchid species is found in forest communities. Half of the orchid species under study occur in the mires and rock habitats with open vegetation. Several orchids consistently occur in areas disturbed by human activity. In addition, our study indicates that the main drivers of orchid distribution across the vegetation types are light and soil nitrogen. Our analysis of the ecological parameters of orchid habitats indicates that some orchid species can be classified as habitat specialists that are confined to a relatively narrow ecological niche in the Urals (e.g., Goodyera repens, Cypripedium guttatum and Dactylorhiza maculata). Several other species (e.g. Neottia cordata and Dactylorhiza fuchsia) grow under diverse ecological parameters.
ABSTRACT
The Ural Mountains (the Urals) are a mountain range on the border between the continents of Europe and Asia. The Urals extend about 2500 km from north to south and run from the coast of the Arctic Ocean to the steppe of northwestern Kazakhstan. In terms of mycorrhizal traits, the vegetation of the Urals has not been studied absolutely compared with the other mountain systems of Europe. Detailed research of vegetation at the Telpos-iz Ridge (Northern Urals, Russia) allowed us to analyze changes in mycorrhizal status (obligatory mycorrhizal, OM; facultative mycorrhizal, FM; non-mycorrhizal, NM) and type (arbuscular, AM; ectomycorrhiza, ECM; ericoid, ERM; ORM, orchid mycorrhiza; NM) both in the main vegetation types and the individual communities along the elevation and ecological gradients based on 165 releves. This is the first attempt to describe the mycorrhizal status of plant communities across different elevations and ecological conditions outside Europe and North America. OM species were most diverse in all vegetation types. Maximal share of NM species was found in the mires and may be explained by over logged and unfertile soils of these habitats. Arbuscular mycorrhizas dominated across all vegetation types except for mires, where specific ecological conditions result in the prevalence of ECM and NM species. We analyzed the mycorrhizal status and type of plant communities along the main ecological gradients and found a decisive role of elevation and soil nitrogen content. At the same time, it remains unclear which factor determines the distribution of ECM and AM communities which are most represented in the vegetation of the study area.
