The effectiveness of asexual and sexual reproduction in clonal species Dianthus superbus L. in different site conditions : the consequences for population development

The effectiveness of asexual and sexual reproduction of rare, clonal species Dianthus superbus L. were conducted in the years 2008-2010 in Kostrze (Southern Kraków). The observations were carried out in Molinietum caeruleae patches dominated by small species creating delicate, erect or procumbent stems (MC), prevailed by tall grasses (GR), and overgrown by willows (SA). The number of above-ground units per ramet cluster were much greater in MC patch, than in sites GR and SA. Controversially, the number of fruit per generative shoot and seed production were greater in GR and SA patches, than in MC patch. The highest seedling recruitment, occurring only in artificially created gaps in plant canopy and litter was noted in patch MC, while the decline of genet emergence were found in SA and GR patches. In light of performed studies, it should be concluded, that population established in patch dominated by small meadow species has the greatest chance for survival, whereas populations inhabiting sites prevailed by tall grasses or overgrown by willows have much lower possibilities of persistence in occupied places

The effect of succession stage on seed rain and seedling recruitment in overgrown Molinia caeruleae meadows

Investigations into the effect of succession stage on seed rain and seedling recruitment were conducted in Kraków-Kostrze (southern Poland) in 2014 and 2015. Observations were carried out in Molinia caeruleae meadows representing early (Patch I), temporary (Patch II) and advanced (Patch III) stage of secondary succession. Patch I was dominated by meadow species creating delicate stems, Patch II abounded in large tussock grasses and tall-growing rhizomatous grasses and Patch III was overgrown by willow shrubs and bordered by trees. The number of seeds and taxa in the seed rain decreased gradually in the successive study sites. Species resident in the standing vegetation were the most abundantly represented in the seed rain and their share augmented remarkably in Patch III, most likely due to its spatial isolation by the surrounding shrubs and trees. The share of seedlings and taxa in artificially made gaps in the plant cover and litter decreases along the successional gradient. The majority of taxa appearing in the seedling pool of all the patches occurred in the seed rain, while the taxa in the soil seed-bank reserves were modestly represented only in Patches I and II. Combining the obtained results and published data, it can be stated that, being abundant in the seed rain, the best colonizers show the greatest germination capability. Although the best colonizers are meadow taxa, fast-growing weeds, trees as well as alien, invasive species also appeared in the seedling pool

The variability of Gentiana pneumonanthe L. subpopulations in different habitat conditions

The impact of habitat conditions on the spatio-temporal variability of abundance and structure of subpopulations of Gentiana pneumonanthe L. was investigated in the years 2013-2015 in patches of abandoned Molinion caeruleae meadows in different stages of successional overgrowing (Patches I-III), as well as in a patch of willow thickets (Patch IV). The height of the standing vegetation and soil humidity increased in successive patches, while the light intensity at ground level diminished gradually. Performed observations showed that abundance of subpopulations decreased from Patch I to Patch IV. Seedlings, juvenile and dormant individuals were not found in all subpopulations, whereas the share of vegetative and generative adults differed significantly. The total number of above-ground units per individual, as well as the height of vegetative stems, increased in consecutive years; moreover, it augmented from Patch I to Patch III and it diminished in Patch IV. The height of flowering stalks rose in consecutive years and in successive patches. The numbers of flowers and fruits in consecutive years were rather constant, whilst in successive study sites they augmented gradually.In light of the performed studies, it might be concluded that the subpopulation occurring in Patch I presents the best state, whereas the subpopulation occurring in Patch IV shows the worst condition and, in the near future, might be eliminated from the colonised site

The impact of disturbance intensity on spatial variability of habitat conditions and seedling recruitment of selected rare, medicinal plants in Molinion patches

The investigations were conducted in two Molinion patches dominated by small meadow species (ME) and overgrown by tall-growing macroforbs (MAC). Observations were carried out in systematically arranged permanent experimental plots divided in experimental subplots. The subplots were subjected to: I) no disturbances; II) low level of disturbance, corresponding with trampling consisting of the litter and moss layer removal; III) intermediate level of disturbance, corresponding with mowing consisting of the litter, moss, and above-ground part of plants removal; and IV) high level of disturbance, corresponding with rooting by wild mammals consisting of the litter, moss and the plants removal, as well as top soil raking with a metal scraper about 7 cm deep. The light availability was greater in Patch ME, while the soil humidity achieved higher values in Patch MAC. At the same time, the light availability increased in consecutive subplots, whereas the soil humidity showed a reversed trend. The cumulative number of seedlings Betonica officinalis and Succisa pratensis in Patches ME and MAC was similar, while Sanguisorba officinalis recruited more abundantly in Patch ME. The greatest number of offspring of all studied taxa was noticed in subplots III and IV. The obtained results might contribute to creating of succesful plans of enlargement of natural resources of medicinal plants in Molinia meadows-one of most valuable semi-natural communities in Europe

Population traits of the rare plant species Succisa pratensis Moench. in meadow overgrowing

This paper examines the population traits of the rare plant species Succisa pratensis Moench. in the course of meadow overgrowing. The investigations were conducted in the years 2010-13, in Molinia caeruleae meadows situated in Kraków- Kostrze (southern Poland). The study sites represented the early (Patch I), medium (Patch II and III) and late (Patch IV) stages of succession. The abundance of subpopulations diminished from Patch I, via Patches II and IV, to Patch III. The increase in abundance in consecutive years was noticed in Patch I; an inverse tendency was found in Patches II and III, whereas lack of variability was recorded in Patch IV. The signs of senescence found in consecutive years in all subpopulations were mostly pronounced in Patches III and IV. The number of rosettes per ramet cluster did not show either temporal or spatial variability. The number of leaves per rosette diminished, while the dimensions of rosette leaves gradually increased in time and space due to diminishing light availability. The number and height of flowering stems, number of cauline leaves, as well as number of flower heads per flowering stem increased from Patch I to Patch III due to lateral shading, and then it diminished in Patch IV due to shading from above. The performed studies indicate that the subpopulation occurring in Patch I has the greatest chance for maintenance in the colonized sites, while the subpopulation occurring in Patch III is the most endangered by extinction

The effect of habitat conditions on the abundance of populations and selected individual and floral traits of Impatiens glandulifera Royle

The effect of site conditions on the abundance of populations of I. glandulifera, selected individual features (height and width of stems, number of whorls and side branches, flower production), and floral traits (total length of flowers, length and width of lower sepal, spur length) were investigated in years 2013-14. Observations were conducted on fallow land, at roadsides, along riverbanks and edges of a riparian forest as well as in a willow thicket and a riparian forest inside located in the Vistula River valley in southern Poland. In these stands, taken successively, light availability gradually diminished, while plant canopy height and soil moisture increased. The low abundance of the population on the fallow land may have been caused by low soil humidity triggering seedling mortality, whereas the low abundance in the interior of the riparian forest may have been due to seasonal water stagnation hampering the development of offspring. The increasing values of individual traits from the fallow land to riparian forest edge might be linked to growing lateral shade, whereas the much lower values in the willow thicket and forest interior might be caused by full shade. Individuals growing on the fallow land, at roadsides, and along riverbanks produced flowers with small total lengths and large lower sepals and spurs, whereas individuals occurring in willow thickets and riparian forests showed opposite tendency. The considerable stem dimensions and substantial production of large flowers may augment chances for successful resource capture and pollinator visits in open sites, while the reduced size of individuals and moderate production of small flowers may be sufficient for the maintenance of populations in closed habitats

The size structure of ramets in Dianthus superbus L. in mosaic meadow vegetation

The present investigations were carried out in the years 2010–2012 in Kraków-Opatkowice (Southern Poland). The observations were conducted in patches of abandoned Molinietum caeruleae meadows with different dominant species. Patch LM was dominated by low meadow species, forming small procumbent shoots and delicate belowground organs; patch TM was occupied by tall-growing taxa creating large tussocks or robust rhizomes; patch SH was overgrown by shrubs and trees with wide spreading roots. In all patches, the number of ramet clusters of Dianthus superbus was low and constant during the whole study period. All populations showed signs of advanced senility due to the absence of individuals in pre-reproductive stages and the occurrence of generative ramet clusters only. The total number of aboveground units per ramet cluster declined, while the leaf length, height of vegetative and generative stems as well as the size of inflorescences and flowers increased from patch LM to patch TM to patch SH. The presented results provide valuable data concerning the state of ramet clusters studied and their prospects for survival in inhabited sites

Effect of cold stratification on seed germination in Solidago × niederederi (Asteraceae) and its parental species

In this study, we investigated the influence of cold stratification on seed germination in S. × niederederi, a hybrid between the North American S. canadensis and the European S. virgaurea, using fruit samples collected in 2016 in Poland. We aimed to test the hypothesis that the low temperature exposure decreases the final percentage and speed of seed germination in the hybrid and its parental species. For each species, sets of 100 achenes in three replications were mixed with dry sand and stored in Petri dishes in darkness for 12 weeks, at -18 ^{\circ}C and + 4 ^{\circ}C, and + 25 ^{\circ}C. The seeds were incubated for 21 d at room temperature (+25 ^{\circ}C), under the 12 h photoperiod (630 lx). We showed a lack of significant differences in: (i) the final percentage of germinated seeds of studied species stored at the same conditions, (ii) the final percentage of germinated seeds between the applied stratification conditions in the hybrid and its parental species, and (iii) the mean values of Timson’s index, mean germination time, and coefficient of velocity of germination between the stratification conditions in each species. The statistically significant inter-specific differences in the mean germination time parameter after the +25 ^{\circ}C treatment suggest that the seeds of S. × niederederi are able to germinate faster than the seeds of its parental species. However, to improve our knowledge of naturalization and invasion abilities of S. × niederederi by sexual reproduction, the seed germination and seedling survival of the hybrid should be tested in the field

The impact of neighbourhood and gap character on seedling recruitment of Trollius europaeus L. and Iris sibirica L. in Molinietum caeruleae meadows

The observations were carried out in the years 2007-2010, in the Molinietum caeruleae meadows with different habitat conditions located in Kraków-Kostrze (southern Poland). The greatest number of seedlings of Trollius europaeus and Iris sibirica was recorded in patches dominated by low-statured species with delicate, procumbent stems or small-tussocks. The diminishing of offspring emergence in places prevailed by large-tussocks grasses, as well as in sites overgrown by willows could be a consequence of poor harvesting practices, as well as the stagnation of water in local depressions. Irrespective of patch charracter, the seedling recruitment did not occur in a fully compact plant canopy, the highest number of offspring was observed in gaps without moss and necromass layers, while the greatest abundance of genets was found in openings left after the removal of bryophytes, litter and above ground parts of plants. The decrease in offspring number noted in gaps resulted from the removal of living and died plants combined with top soil raking, which might caused the partial depletion of soil seed bank reserves. Regardless of the patch type, a significantly higher appearance of seedlings of Trollius europaeus and Iris sibirica was found in the largest gaps than in the smallest ones. In light of the performed studies, it might be concluded that gap creating seems to be a very effective way of active protection of Iris sibirica and Trollius europaeus populations

The influence of neighbouring species on ecological variation of the selected subpopulations of Iris sibirica L.

Ecological variation of the selected subpopulations of Iris sibirica L. were studied in the years 2011-2012, in the abandoned patches of Molinietum caeruleae dominated by small meadow species (Patch I), macroforbs (Patch II), largetussock grasses (Patch III), shrubs (Patch IV), as well as shrubs and trees (Patch V). The abundance of subpopulations and dimensions of aggregations of ramet clusters increased gradually from Patch I to Patch IV and subsequently declined in Patch V. During the whole study period, all subpopulations showed signs of senility due to the absence of individuals in prereproductive stages. The share of generative ramet clusters diminished, while contribution of senile and fragmentised ramet clusters increased substantially in consecutive patches. The dimensions of ramet clusters increased significantly in successive plots and years. The number and height of generative stems and production of flowers and fruits did not show the temporal variability. The abundance of generative stems was considerably lower in the plots dominated by small meadow species, than in the sites dominated by large-tussock grasses, shrubs or overgrown shrubs and trees. Both the height of flowering stems and production of flowers and fruits increased gradually from Patch I, via Patches II, III and IV, to Patch V. The augmentation of flower production might contribute to better visibility of inflorescences for pollinators, whereas an increase in the production of fruits may increase the chances for successful seed dispersal to new sites. This study results show that the I. sibirica subpopulations occurring in the site dominated by small meadow species and macroforbs were in unsatisfactory condition, those inhabiting the sites dominated by large-tussock grasses and shrubs were in a quite good condition, while the subpopulation inhabiting the plot overgrown by shrubs and trees showed the worst condition Ecological variation of the selected subpopulations of Iris sibirica L. were studied in the years 2011-2012, in the abandoned patches of Molinietum caeruleae dominated by small meadow species (Patch I), macroforbs (Patch II), largetussock grasses (Patch III), shrubs (Patch IV), as well as shrubs and trees (Patch V). The abundance of subpopulations and dimensions of aggregations of ramet clusters increased gradually from Patch I to Patch IV and subsequently declined in Patch V. During the whole study period, all subpopulations showed signs of senility due to the absence of individuals in prereproductive stages. The share of generative ramet clusters diminished, while contribution of senile and fragmentised ramet clusters increased substantially in consecutive patches. The dimensions of ramet clusters increased significantly in successive plots and years. The number and height of generative stems and production of flowers and fruits did not show the temporal variability. The abundance of generative stems was considerably lower in the plots dominated by small meadow species, than in the sites dominated by large-tussock grasses, shrubs or overgrown shrubs and trees. Both the height of flowering stems and production of flowers and fruits increased gradually from Patch I, via Patches II, III and IV, to Patch V. The augmentation of flower production might contribute to better visibility of inflorescences for pollinators, whereas an increase in the production of fruits may increase the chances for successful seed dispersal to new sites. This study results show that the I. sibirica subpopulations occurring in the site dominated by small meadow species and macroforbs were in unsatisfactory condition, those inhabiting the sites dominated by large-tussock grasses and shrubs were in a quite good condition, while the subpopulation inhabiting the plot overgrown by shrubs and trees showed the worst conditio