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Abstract

This paper reports the results of observations of the abundance of population Succisa pratensis Moench, as well as temporal and spatial variabilities of chosen traits such as the number of rosettes, number of leaves per rosette, number and height of flowering stems, number of flower heads per generative stem and number of seeds per fruit. Investigations were conducted in the years 2009−2013, in six patches of Molinietum caeruleae with different dominant species, unmanaged from 10 to 22 years. On the basis of studies performed, the state of populations and chances for maintenance in the colonised site were evaluated.

Abstract

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

Abstract

This paper evaluates the selected population-biological characteristics and size structure of invasive neophyte Asclepias syriaca in three habitat types (abandoned vineyards, grassland and road side) in the district of Veľký Krtíš in Central Slovakia. Three permanent research plots (1 m × 1 m) were established and monitored during the growing season in 2012. The density of the population at the end of the growing season ranged from 15 to 29 stems per m2. The greatest average plant height was recorded in the roadside plot (129 cm) and the lowest in the abandoned vineyard (92 cm). Main stem thickness reached 1.5-2.0 cm at the base. The highest number of main stem leaves was recorded at the end of June and July (from 24 to 27). The number of inflorescences varied from 1.6 to 3.4 and the number of fruits ranged from 1.2 to 3.8 per generative stem. Statistically significant differences were found in the plant height, thickness of the main stem and the number of fruits at the three different locations.

Abstract

The investigations presented here were carried out in years 2013-14, in a Molinietum caeruleae meadow with interrupted plant cover caused by animal activity (patch I); abandoned Molinietum caeruleae meadows with untouched plant canopy, dominated by species with considerable height of the above-ground parts (patches II-VI); as well as the edge (patch VII) and the interior (patch VIII) of a birch woodlot. The height of standing vegetation and soil moisture increased in subsequent patches, whereas the light availability at ground level showed inverse tendency. The abundance of Trollius europaeus subpopulations in all studied patches was rather low. In patch I, juvenile individuals dominated, while in other stands - flowering adults prevailed. The lack of temporal variability in the number of basal leaves observed in patches III, IV, V, VI and VII might be due to lack of available area necessary for clonal proliferation of ramets, while the increase of basal leaves number in other sites might suggest unlimited iterative growth. The dimensions of basal leaves in consecutive years were constant in majority of subpopulations, while they showed strong spatial variability increasing gradually from patch I to patch VII and, subsequently, decreasing in patch VIII. The substantial dimensions of basal leaves may enable better light capture in sites with great level of lateral shade, while smaller dimensions in patches located within a woodlot may be due to shade from above created by trees. Lack of temporal variability and presence of substantial spatial variability in the number and height of generative stems, as well as flower production might enhance chances for successful pollination in a competitive environment. Significant changes of follicle number in time and space suggest successful process of pollination in all patches excluding patch VIII. The weak condition of the ramet clusters in patch I is not compensated by considerable seedling recruitment, whereas the satisfactory state of the ramet clusters in patches II-VIII may not suffice for the long-term maintenance of populations in colonized areas.