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PajÄ ki potencjalnymi zapylaczami gatunkĂłw inwazyjnych? WpĆyw aktywnie polujÄ cych i sieciowych pajÄ kĂłw na sukces reprodukcyjny inwazyjnej tawuĆy kutnerowatej (Spiraea tomentosa)
Intra- and interspecific pollen morphology variation of invasive Reynoutria taxa (Polygonaceae) in their response to different habitat conditions
Although understanding the relationship between the reproductive mode and mass-dispersal potential of plants is crucial for studying invasion phenomena, the morphological features of invasive speciesâ pollen are not well understood. This study examined the pollen morphology and variability of three Reynoutria (knotweed) taxa (R. japonica, R. sachalinensis, R. Ă bohemica) invasive in Europe, and their reaction to different habitat conditions within seven distinguished habitat types. The pollen was sourced from 95 sites from the taxaâs invasive range in Central Europe. In total, 2850 pollen grains were measured and analysed for 11 quantitative and qualitative features. The pollen of R. sachalinensis was distinguished from that of the other two taxa (reticulate perforate) based on its rugulate and fossulate perforate exine ornamentation. The pollenâs response to various habitat conditions, which was most marked in R. Ă bohemica, was reflected by pollen size and exine thickness. Our research indicates that pollen availability is not a limiting factor for the sexual reproduction of knotweeds in Central Europe, including Reynoutria japonica, long considered male sterile. The observed presence of male-fertile specimens of R. japonica may enhance the efficiency of generative reproduction in this species throughout its invaded ranges. This finding should be considered when planning actions to control the population of these transformer plant species.
Nowe stanowiska roĆlin naczyniowych Polski, 4
W pracy przedstawiono nowe stanowiska 15 rzadkich w skali kraju lub regionu roĆlin naczyniowych, tj. <i>Allium scorodoprasum</i>, <i>Ambrosia artemisiifolia</i>, <i>Blechnum spicant</i>, <i>Carex bohemica</i>, <i>Dactylorhiza incarnata</i> subsp. <i>incarnata</i>, <i>Dianthus superbus</i>, <i>Epipactis albensis</i>, <i>E. purpurata</i>, <i>Fritillaria meleagris</i>, <i>Lycopodiella inundata</i>, <i>Ophioglossum vulgatum</i>, <i>Oxytropis pilosa</i>, <i>Rubus laciniatus</i>, <i>R. praecox</i>, <i>Trapa natans</i> oraz pierwsze stanowisko <i>Verbena bonariensis</i> w Polsce.
Nowe stanowiska roĆlin naczyniowych Polski, 5
W pracy przedstawiono nowe stanowiska 18 rzadkich (lub regionalnie rzadkich) roĆlin naczyniowych w Polsce, tj. <i>Abutilon theophrasti, Aquilegia vulgaris, Carex bohemica, C. tomentosa, Crocus speciosus, Erechtites hieraciifolia, Lathyrus nissolia, Lunaria annua subsp. annua, Lycopodiella inundata, Myricaria germanica, Nymphaea candida, Ophioglossum vulgatum, Potentilla indica, Pulicaria dysenterica, Rubus kaznowskii, Scilla sardensis, Solidago Ăniederederi</i> oraz <i>Veratrum lobelianum</i>.
Phenological gap in fruiting period and dispersal of seeds from alien fleshy-fruited plants by medium-sized carnivores in temperate forests of Central Europe
Some biological differences between native and alien plants are relevant to their dispersal mechanisms. One of them is the fruiting period: it is shifted in time, peaking later than in natives. Here we report the case study showing the temporal distance in fruiting phenology between native and alien plants and their seed dispersal via carnivorous mammals. From 2009 to 2011, scats of badgers Meles meles, foxes Vulpes vulpes, martens Martes spp. (M. martes and M. foina) and possibly also raccoon dogs Nyctereutes procyonoides (N = 820) were collected along transects totaling 30.4 km in length each month from June to November. We analyzed the frequency of occurrence of seeds (FO%) and the seed load in sampled scats; 61.7% of the sampled feces contained seeds of 18 fleshy-fruited native and alien plant taxa, and the most abundant seeds were from species with multi-seeded fruits such as Vaccinium myrtillus (94.6%), Rubus sp. (2.0%), and drupes of Prunus serotina (1.0%). The structure of dominance was characterized by seeds of Vaccinium myrtillus (15.0%), Pyrus sp. (14.8%) and Prunus serotina (13.0%) with aliens reaching high frequency of occurrence (FO%). The shares of seed FO% in the samples differed between alien and native plants. For seed load there were also significant interactions between the status of the seeds (alien or native) and the month of the vegetation period. Our data show the coincidence of two factors â the late fruiting period of alien plants and the decreasing availability of native fruits during the vegetation period. Such a set of factors may promote the dispersal of alien plant seeds by carnivorous mammals, which, unlike migrating birds, are constantly present in autumn. The limited availability of native fruits after their fruiting period, creating a phenological gap, makes alien plants the main source of fleshy-fruits at the end of vegetation period in forest ecosystems; this is expressed in high proportion of alien plants in seed FO%, and in significant interactions in the seed load in carnivore scats.
Low Rate of Pre-Dispersal Acorn Predation by Eurasian Jays Garrulus glandarius during Non-Mast Years
Setts of European badger Meles meles in open habitats: trend or exception?
AbstractReports on the location of badger setts generally focussed on woodland habitats and paid little attention to open areas. There was a negative correlation between the number of setts in open landscape and the proportion of forest cover with an inflection point at 25â35%. A higher proportion of badger setts in open habitats is observed when forest cover is below the inflection point. The location of setts in the open landscape results from the dominance of these habitats and the low availability of woodland and that is a permanent aspect of badger behaviour and not a shortâterm trend.
Consequences of Spiraea tomentosa invasion in Uropodina mite (Acari: Mesostigmata) communities in wet meadows
AbstractVegetation cover has been consistently reported to be a factor influencing soil biota. Massive spreading of invasive plants may transform native plant communities, changing the quality of habitats as a result of modification of soil properties, most often having a directional effect on soil microorganisms and soil fauna. One of the most numerous microarthropods in the litter and soil is Acari. It has been shown that invasive plants usually have a negative effect on mites. We hypothesized that invasive Spiraea tomentosa affects the structure of the Uropodina community and that the abundance and species richness of Uropodina are lower in stands monodominated by S. tomentosa than in wet meadows free of this alien species. The research was carried out in wet meadows, where permanent plots were established in an invaded and uninvaded area of each meadow, soil samples were collected, soil moisture was determined and the mites were extracted. We found that Uropodina mite communities differed in the abundance of individual species but that the abundance and richness of species in their communities were similar. S. tomentosa invasion led primarily to changes in the quality of Uropodina communities, due to an increase in the shares of species from forest and hygrophilous habitats. Our results suggest that alien plant invasion does not always induce directional changes in mite assemblages, and conclude that the impact of an alien species on Uropodina may cause significant changes in the abundance and richness of individual species without causing significant changes in the abundance and diversity of their community.
Comparison of Pearsonâs and Spearmanâs correlation coefficients for selected traits of Pinus sylvestris L.
Abstract The Spearman rank correlation coefficient is a non-parametric (distribution-free) rank statistic proposed by Charles Spearman as a measure of the strength of the relationship between two variables. It is a measure of a monotonic relationship that is used when the distribution of the data makes Pearsonâs correlation coefficient undesirable or misleading. The Spearman coefficient is not a measure of the linear relationship between two variables. It assesses how well an arbitrary monotonic function can describe the relationship between two variables, without making any assumptions about the frequency distribution of the variables. Unlike Pearsonâs product-moment (linear) correlation coefficient, it does not require the assumption that the relationship between variables is linear, nor does it require that the variables be measured on interval scales; it can be applied to variables measured at the ordinal level. The purpose of this study is to compare the values of Pearsonâs product-moment correlation coefficient and Spearmanâs rank correlation coefficient and their statistical significance for six morpho-anatomical traits of Pinus sylvestris L. (original â for Pearsonâs coefficient, and ranked â for Spearmanâs coefficient) estimated from all observations, object means (for trees), and medians. The results show that the linear and rank correlation coefficients are consistent (as to direction and strength). In cases of divergence in the direction of correlation, the correlation coefficients were not statistically significant, which does not imply consistency in decision-making. Estimation of correlation coefficients based on medians is robust to outlier observations and factors that linear correlation is then very similar to rank correlation.