Kinga Kostrakiewicz-Gierałt

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

Abstract 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 habitat conditions on the performance of two invasive, annuals — Impatiens glandulifera and Bidens frondosa

The investigations of habitat conditions on the variability of selected population features in the two invasive, annuals with different life-history traits were conducted in the years 2008–2010, in the Polish part of the Carpathian Mountains in communities characterized by the gradual decrease of light availability. The individuals of Impatiens glandulifera were surveyed along roadsides, in willow thickets, as well as inside and along the edges of the riparian forest, whereas the individuals of Bidens frondosa were observed in riverside gravels characterized by a different species composition. Each year, the number and density of individuals (stems) occurring in the particular sites were examined, as well as the height and the fruit production in 30 randomly chosen stems were surveyed. Moreover, the number of seeds per fruit, the diaspore dimensions and the seedling recruitment in laboratory conditions were examined during each season. As the values of height of individuals, number of fruits per stem, number of seeds per fruit, as well as the seedling abundance in some groups were not consistent with the normal distribution and the variances were not homogeneous, the non-parametric Kruskal-Wallis test was used in statistical analyses.Much greater number and density of individuals of Impatiens glandulifera were found in riparian forest, than in willow thickets and along the roadsides. In all sites the number and density of individuals increased steadily in consecutive seasons. The great number and density of Bidens frondosa individuals observed in shady and partly shady sites during the first year of studies raised in the second year and subsequently dramatically decreased in the third season. The lowest number and density of individuals noted in the first season in unshaded site raised substantially in subsequent years. The height of stems, as well as seed and fruit production of both taxa diminished with a decrease of height of neighboring plants. The seed dimensions presented the spatial and temporal variability, whereas the number of seedlings among consecutive years and in successive sites did not differ.The considerable height of the individuals of Impatiens glandulifera, high production of large fruits and seeds in open and dry roadside areas can contribute to more effective ballistic dissemination, while substantial seedling recruitment enables the colonization of new, perhaps more advantageous sites. On the other hand, lower individual height, as well as fruit and seed production and considerable seedling emergence allow the population to last and to gradually extend the area in forest communities. The considerable abundance of the high-statured Bidens frondosa individuals, substantial production of large capitula and achenes contribute to long persistence of populations in open and sun-lit sites. The gradually decrease in the height of the stems, achene number and size observed in partly-shaded and shaded places might allow to long-distance dispersal of seeds by animals, while substantial seedling recruitment might contribute to establishment in new areas.

Are Deschampsia caespitosa (L.) Beauv. Tussocks Safe Sites for Seedling Recruitment in the Succession of Wet Meadows

ABSTRACT: In stressful and harsh environments, safe sites for seedling recruitment may be created by nurse plants, which accumulate propagules and subsequently facilitate the establishment of individuals. The main goal of the presented studies focused on observations of seedling recruitment in small and large tussocks of Deschampsia caespitosa derived from patches of unmanaged Molinietum caeruleae meadows situated along the successional gradient and dominated by small meadow species (Patch I), by macroforbs (Patch II), or overgrown by trees and shrubs (Patch III). The studies showed that, irrespective of patch character, Serratula tinctoria, Selinum carvifolia, Lysimachia vulgaris and Filipendula ulmaria are among the best colonizers of Deschampsia caespitosa tussocks. The gradual decrease in number of species and offspring abundance along the successional gradient may be connected with a prolonged period of water stagnation accelerating the development of fungal pathogens, a major cause of mortality for buried diaspores. The growing frequency of species present in standing vegetation and the gradually rising contribution of swamp and forest taxa in consecutive patches may be due to the production of non-persistent diaspores by early successional species, as well as reduced seed immigration from neighboring sites. The obtained results included evidence that, regardless of patch character, the percentage of seedlings representing species present in and absent from existing vegetation as well as taxa with various vegetation types is similar in small and large tussocks. Furthermore, in small tussocks, regardless of patch character, anemochorous and hydrochorous taxa dominated, the frequency of endo- and epizoochorous taxa was much lower, while the percentage of species characterized by other modes of diaspore dispersal attained the lowest rates. In large tussocks, anemochorous and epizoochorous species prevailed, the share of endozoochorous and hydrochorous taxa was lower, and the contribution of species characterized by other modes of dissemination was very scarce. On the basis of these studies it might be concluded that, despite the successive decrease of species and seedling abundance, and along with the increase in the recruitment of taxa resident in standing vegetation, especially woody species, the tussocks of Deschampsia caespitosa are reservoirs of meadow species even in advanced successional stages and may play a significant role in the process of long-term species turnover.

The Effect of Neighbouring Plant Height, Disturbance Level and Gap Size on Spontaneous Recruitment of Large-Seeded And Small-Seeded Species in Molinietum caeruleae Meadows

ABSTRACT: The seed size is considered as a key feature, which effects both: colonizing and competitive abilities of species. The disturbance dependent small-seeded taxa are regarded as superior colonists, whereas the large-seeded taxa are considered as best competitors able to survive the competition from adjacent plants and negative effect of litter. The impact of character of standing vegetation, disturbance level and size of gaps on spontaneous recruitment of seedlings of selected light-seeded species (Gentiana pneumonanthe L., Dianthus superbus L.) and heavy-seeded taxa (Serratula tinctoria L., Gladiolus imbricatus L.) were conducted. The investigations were carried out in two areas (A and B). Both of them were consisted of three adjacent patches of Molinietum caeruleae: dominated by small meadow species (labeled MC), prevailed by large-tussocks grasses (labeled GR), and overgrown by willows (labeled SA). In the year 2007, in all patches, ten permanent experimental plots were randomly arranged. In Area A, plots were divided in four square-shaped, neighboring subplots subjected to: no treatment; the removal of litter and moss layers; the removal of litter, bryophytes, and above-ground parts of plants; the removal of litter, moss and the plants, as well as top soil stripping. In the Area B, plots were divided into four subplots measuring from 0.16 m2 to 0.01 m2. In each of them the litter and above-ground part of plant biomass were clipped and removed. The recruitment of seedlings was monitored from 2007 through 2010. In both studied areas, regardless of seed mass, the greatest abundance of seedlings were found in patches MC, and decreased gradually in sites GR and SA. Irrespective of seed size, in subplots where plant cover and litter stayed intact no new genets was noted, moderate appearance of seedlings was observed in subplots without plant necromass, whereas the greatest number of generative progeny was found in subplots without necromass and aboveground parts of plants. The lower abundance of seedlings in subplots without litter, plants and topsoil might have been caused by depletion of seed bank reserves. Moreover, in all patches the number of seedlings of small- and large-seeded taxa increased significantly with augmentation of gap size. In light of performed studies it might be concluded, that the disturbances might play very important role in active protection of studied taxa. The positive impact of disruption diminishes with increasing of plant canopy height. The removal of plant cover and litter contributes to the greatest seedling recruitment but its beneficial effect diminishes with decreasing of opening size.

The influence of standing vegetation height on the reproductive allocation In populations of Serratula tinctoria L. (Asteraceae)

ABSTRACT: The advantage of the clonal plants over the nonclonal species in colonization of all biomes and biogeographical regions primarily is due to occurrence of two modes of reproduction. The creating of vegetative propagules with high vitality and survivability, enables the spread in the newly colonized site, while seed production increases the chances for successful recruitment of seedlings, ensuring the genetic diversity of the population. The differences in allocation into vegetative reproduction and generative propagation in relation to rising height of adjacent plants was investigated in populations of Serratula tinctoria L., occurring in Molinietum caeruleae meadows localized in Southern Poland. Each locality was represented by randomly established three permanent study plots: dominated by small meadow species (LOW), prevailed by large-tussock grasses (INTER) and overgrown by shrubs and trees (HIGH). In the years 2009–2011 the number of leaf rosettes and length of the longest leaf in rosette (as a measure of allocation in vegetative propagation), as well as height of generative stems, number of capitula per stem and number of seeds per capitulum (as indicators of investment in generative reproduction) were observed. The allocation in vegetative reproduction decreased along the gradient of vegetation height. The gradually decline of number of rosettes might be caused by lack of free space suitable for establishment of new ramets, whereas the small leaf size could be due to drastically augmentation of shading. The allocation in generative reproduction increased along the gradient of vegetation height. The placement of structures necessary for generative propagation in higher layers of herbaceous canopy, as well as considerable number of capitula and seed production might increase the chances for successful recruitment of seedlings. On the basis of obtained results combining with published data it should be assumed, that the substantial allocation in vegetative reproduction and the slight investment in generative propagation seems to be sufficient for persistence of Serratula tinctoria populations in patches dominated by small meadow species, while the considerable allocation in generative reproduction could be crucial for maintenance of population viability under competitive conditions.

The Variability of Selected Features of Gladiolus imbricatus L. in Relation to Successive Stages of Meadow Communities Following the Mowing Cessation

ABSTRACT: Molinietum caeruleae meadows belong to the most endangered plant communities in Central Europe, nowadays suffering due to the lack of management. The land abandonment promotes strong secondary expansion of macroforbs, sedges or willows, contributing to decrease of the species diversity. In light of these findings very interesting seems to be the evaluation of the variability of features of populations of rare meadow species. In Poland one of strictly protected plant is Gladiolus imbricatus L. It is a tuberous, clonal plant with sword-like leaves and tall stalks bearing purple flowers collected in one-sided inflorescence. The studies of spatio-temporal variability of selected features of subpopoulations of Gladiolus imbricatus were carried out in the years 2009– 2011 in Kraków-Kostrze (Southern Poland) in patches of Molinietum caeruleae with different species composition. In Patch I chiefly occurred small meadow species, Patch II was prevailed by shrub willow, Patch III was dominated by tall-growing macroforbs, Patch IV was characterized by substantial share of large-tussock grasses, while Patch V was overgrown by tall rhizomatous grass Phragmites communis. The plant canopy height and ground moisture raised from Patch I, via Patches II, III and IV, to Patch V. Moreover, in all sites the above mentioned parameters increased moderately in consecutive seasons. The decline of abundance of subpopulations observed in the consecutive years and in the successive patches might be caused by a mortality of individuals, a physical damage of tubers, as well as a prolonged dormancy of genets. The structure of developmental stages were similar in consecutive years but differed significantly among Patches. The increasing trend toward senility noted in successive sites could be an effect of lack of microsites suitable for seedling recruitment or absence of vegetative regeneration. The dimensions of leaf blades, flowering stalks and inflorescences remained similar in the subsequent seasons, but they augmented significantly in the successive patches. The length and the width of capsules did not change significantly between seasons and sites. Concluding, it might be assumed, that the perspectives for survivability of subpopulations diminish gradually from Patch I, via Patches II, III and IV to Patch V. Simultaneously, it should be pointed out that prospects for persistence in each place steadily decrease in effect of continuous deterioration of site conditions.

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

Abstract 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 riverbanksproduced 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 Impact of Succession Stage on Share and Traits of Clonal Plants in Abandoned Molinion caeruleae Meadows

The impact of succession stage on the share of clonal plants in the plant cover, seed rain and seedling pool has been studied in the years 2014 and 2015. The investigations were carried out in abandoned Molinion caeruleae meadows dominated by small-statured species (Patch I), tall growing large-tussock grasses (Patch II) and shrub-willows (Patch III). Although the clonal taxa dominated in the plant cover, seed rain and seedling pool, their share in subsequent study sites was quite different. The spectra of life-history traits relevant to clonality in the plant cover and seed rain were similar and did not vary significantly among subsequent locations, while they mostly differed as observed in the seedling pool. The various spectra observed in seedling pool in subsequent study sites might be due to fact that the seed germination and recruitment of offspring are strongly influenced by habitat conditions which varied remarkably in the successive Patches.

Variability of Morphological Traits of the Rare Plant Species Angelica palustris (Apiaceae) in Managed and Abandoned Meadows: Effect of Mowing

ABSTRACT The effect of meadow management type on selected population traits of the rare plant Angelica palustris was examined. The study was carried out in a regularly mown meadow (Plot I), an abandoned meadow with medium high plants (Plot II) and an abandoned meadow with high plants (Plot III) situated in southern Poland (Proszowice Plateau). Observations conducted in the years 2010 and 2011 showed greater abundance of A. palustris in Plot I than in Plots II and III. This pointed to the significance of disturbance caused by mowing, which creates gaps in the plant cover and litter layer that become safe sites for A. palustris seedling recruitment and their subsequent growth. In the abandoned meadows a diminishing share of vegetative individuals and a reduction in the number of flowering stems in generative individuals were found. The height of generative stems in the abandoned meadows was higher than in the mown one as a response to the height of neighbouring plants. The number of umbels per stem and number of umbellets per umbel were positively correlated with the height of the stem. In light of our investigations, it can be stated that regular mowing has a beneficial effect on the state of populations of A. palustris. On the other hand, the formation of highly productive generative stems with substantial numbers of inflorescences and infructescences in abandoned meadows may promote successful seed dispersal and an escape from an unfavourable site.

The Influence of Vegetation Structure on the Composition of the Seed Rain and Seedling Pool in Abandoned Molinion caeruleae Meadows

ABSTRACT The investigations of the effect of different habitat conditions on the composition of the seed rain and seedling pool were conducted in the years 2014 and 2015 in abandoned patches of Molinion caeruleae dominated by small-stature meadow taxa (patch I), tall-growing grasses (patch II), as well as shrubs and trees (patch III). Observations showed that along the successional gradient the seed rain and seedling pool diminishes. The prevalence of perennials and native taxa in the seed rain and seedling pool occurred in all the study sites. Moreover, in the propagule and seedling pools of all the patches hemicryptophytes and meadow taxa prevailed but their number decreased in successional sites. Also, the abundance of ruderal and grassland taxa decreased gradually, at expense of number of forest species. Zoochorous species prevailed in the seed rain and seedling pool of all patches. Number of hydrohorous species decreased in successional patches, while the abundance of species with other dispersal modes were similar. Irrespective of patch character, the species producing propagules with medium size dominated in the seed rain and seedling pools, whereas a significant decrease of number of small-seeded species was noticed only in the seedling pool. Despite the diminishing of the seed rain and seedling pool along the successional gradient, the gap creation might be a very effective way of active protection of Molinion caeruleae meadows. However, the gap colonisation requires permanent monitoring to avoid further spreading of undesired taxa.