The complex Gymnadenia conopsea s.l. represents a very problematic group in terms of taxonomy, showing a wide morphological, phenological, genetical and cytogenetical variability. The aggregate G. conopsea encompasses a range of taxa, two of which, G. conopsea (L.) R. Br. s.s. and G. densiflora (Wahlenb.) A. Dietr., have been acknowledged as beeing a species level. Individual taxa cannot be safely distinguished on the basis of morphological characteristics in all cases. Recently, there has been a lot of discussion concerning the taxonomical value of taxons within the G. conopsea complex. The complex is represented by a variety of cytotypes, while the major tetraploid cytotypes represent the above mentioned G. conopsea and G. densiflora taxa, that are easily distinguishable by means of flow cytometry. The taxonomical classification of minority cytotypes is not clear. For these reasons, to be able to obtain more detailed information, an application of different approaches from the field of morphology, cytogenetics and molecular genetics is suitable when evaluating the populations. In this thesis, morphological characteristics, AFLP and an analysis of microsatellites along with a measurement of ploid level using FCM have been used for evaluation. On the basis of evaluating a multidimensional cluster analysis and a dendrogram created by the UPGMA method combining these data, a specific dissimilarity of the G. densiflora and G. conopsea taxon has been confirmed. Based on the comparative analysis of microsatellite loci and overlapping morphometric characteristics of tetraploid and octoploid G. conopsea cytotype it can be assumed that the octoploid cytotype is a separate chromosomal aberration of tetraploid plants.

Reproductive isolation can be achieved through multiple types of barriers and is essential for speciation. In flowering plants, pre-pollination barriers (e.g. differentiation in pollination niches) are believed to be the most efficient at preventing gene flow across species boundaries. In closely related species that come into secondary contact, such barriers can evolve to prevent competition for pollinator service and/or interspecific pollen transfer, which can have fitness costs. Hence pollination niche differentiation should be stronger in sympatric populations than in allopatric populations (i.e. character displacement). To investigate the differences in pollination niches and to see if it is consistent with a hypothesis of character displacement, I used the two closely related and phenotypically similar orchid species, Gymnadenia conopsea and G. densiflora. I sampled mixed and pure populations of G. conopsea and G. densiflora on Öland during the summer of 2020. In these populations, I used video cameras and pollinator catches to record pollinator activity and characterize the composition of pollinator communities. Estimation of pollinator efficiency was also assessed by analyzing the number of pollinia carried by each pollinator. Contrary to my expectations, I found that both orchids had their visitation peak during the night and that the most frequent and efficient pollinators were Autographa gamma or Deilephila porcellus for both of them. Furthermore, no increased differentiation between the two species was found in mixed compared to pure populations. My results suggest that plant-pollinator interactions do not act as efficient pre-pollination barriers in these two orchid species, and that competition for pollinator service and through interspecific pollen transfer seem to be too weak to drive pollination niche partitioning.

The subject of this diploma thesis was the research of vegetation at localities in the Protected Landscape Area Bohemian Paradise. There were choosen areas: Natural Monument Podloučky and Protected Area Fialník, where grows an orchid Gymnadenia conopsea subsp. montana. There were made 60 phytocenological samples, and described: biotop, altitude, slope, huminidy and exposure. There were found four orchid species in the localities. Phytocenological samples were compared with each other. It has been shown that differences between localities are greater than the differences between orchid and non-orchid samples. Significant differences were also found in comparing the coverage in the floor between locations and abundace of species in each floor.

A wide majority of orchid populations are decreasing due to habitat fragmentation and to changes in land management. Population size, density and habitat quality are factors that are expected to be positively related to the viability and future growth of a population. We evaluated if population size, density and soil organic matter were good predictors of growth, survival, flowering, recruitment, and growth rate in 18 populations of the long-lived orchid Gymnadenia conopsea. We followed the populations for four years. Recruitment in 2020 increased with population size, and survival in 2018 was higher in denser populations. However, flowering probability and number of flowers both decreased with population size in 2018. Soil organic matter did not significantly influence any vital rate. In total, the studied population factors could explain very little of the variation in demography. The matrix modelling showed that 14 of the 18 populations had a positive stochastic growth rate, even with an increased probability of summer drought (scenario with 50% of the years equal to the dry summer of 2018). In the populations with negative growth rate, the probability of quasi-extinction in the next 50 years varied from 90 to 100%. Declining populations were characterized by low survival following the dry year. In sum, population size, density and soil organic matter did not convincingly explain variation in growth rate of G. conopsea, suggesting that other environmental factors are responsible of governing variation in vitals rates and population dynamics.