The alpine-boreal plants which have survived in Central European lowlands during glacial periods depend both on the preservation of their refugial habitat, and their capability for vegetative and generative reproduction and dispersion. Pulsatilla vernalis (L.) Mill. is a model species which occurs throughout most of the European alpine system, as well as in isolated populations in the lowlands. At present, the relict lowland localities of this species often have a historic character. In the Polish lowlands, only the population located in Rogowiec is characterized by effective recruitment. It presents a large number of rosettes and a diversified demographic structure, with plants in all stages of development. The study examines the population in Rogowiec from 2002 to 2008 with regard to the number of flowering and fruiting shoots, new seedlings, and loss of juvenile rosettes, and the obtained data are correlated with climatic conditions. Three years were found to demonstrate effective recruitment, with numerous seedlings and little loss of juvenile rosettes. No significant relationship was found between seedling dynamics and the flowering-fruiting process. However, correlations were found between effective renewal and some climatic factors. Temperature, water balance, and solar radiation were found to have a limiting effect on the reproduction and regeneration of the analyzed relict population. Due to the longevity of the rosettes, favorable climatic conditions occurring every few years are sufficient for survival of the species in this location. However, serious threats are posed by the climate change trends expected in Europe over the coming decades, and the fact that due to its small-scale dispersal ability, the analyzed species occupies only a small area in Rogowiec.

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Species distribution models need adequate sets of data, particularly in the case of range‐restricted species. The problem faced in the modeling of rare species is twofold: a small sample size and the occurrence of sampling biases. The present analysis combines spatial‐ and habitat‐thinning approaches to improve maximum entropy models based on geographically incomplete data of relict and subendemic Festuca amethystina L. grass on Polish territory. The results show that models based on strongly incomplete historic data did not predict the occurrence of all important areas where the species was found in the following decades. However, the introduction of species‐specific thinning allows for more precise prediction of the species range, i.e., the detection of suitable areas on a more local scale. The introduction of habitat thinning caused the diversity of important predictors in model to increase, but spatial thinning decreased the number of significant predictors and made interpretation easier. Additionally, a combination of thinning techniques allowed significant improvements to be made to the model predictions after the experimental addition of a lower number of localities to regions which had previously been poorly recognized. It can be concluded that in the case of incomplete data, the above corrections allow the true range of the species to be predicted after the discovery of a lower number and relatively dispersed new localities.

BackgroundPolyploid specimens are usually characterized by greater exuberance: they reach larger sizes and/or have a larger number of some organs. Festuca amethystina L. belongs to the section Aulaxyper. Based on morphological features, four subspecies of F. amethystina have been already identified. On the other hand, it has two cytotypes: diploid and tetraploid. The main aim of our study was to distinguish morphological differences between the cytotypes of F. amethystina, assuming that its phenotype differs significantly.MethodsThe nuclear DNA content was measured by flow cytometry in dry leaves from specimens originating from 13 populations of F. amethystina. Several macrometric and micrometric traits of stems, spikelets and leaf blades were taken into account in the comparative analysis of two cytotypes.ResultsIn the case of cytotypes, specimens of tetraploids were larger than diploids. The conducted morphometric analysis of leaf cross-sections showed significant differences between the cytotypes.DiscussionThe research has confirmed for the first time that in the case of F. amethystina the principle of greater exuberance of polyploids is true. Differences between the cytotypes are statistically significant, however, they are not enough to make easy the distinction of cytotypes on the basis of the measurements themselves. Our findings favor the rule known in Festuca taxonomy as a whole, i.e. that the ploidy level can be one of the main classification criteria.

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