Małgorzata Wrzesień

The importance of field-margin location for maintenance of food niches for pollinators

Abstract Understanding the factors that have an impact on the diversity of forage flora in the agricultural landscape is a key issue in the maintenance and control of food niches for pollinators. Field margins are common linear structures in the agricultural landscape. In the present study, we evaluated the factors that exert an impact on the forage flora composition and on the diversity in field margins. The study was conducted in the 2010 - 2011 time period across the agricultural landscape on the Lublin Upland of SE Poland. Data on the forage flora were obtained while making floristic charts along 45 transect plots x 300 m; the total length being 13500 m. Multivariate ordination techniques (PCA and RDA) were employed to analyse forage-flora characteristics. Field margins represent valuable refuge areas for forage-species richness, but not for the abundance of forage species. On field margins, forage-species diversity benefits from the location of natural habitats (forests or meadows), primarily if the distance from these habitats is <1000 m or the field acreage is <10 ha. The shift from heterogeneous habitats to a more homogeneous landscape causes a reduction of forage floral diversity. Due to lack of dense forage-species patches, the promotion of sowing nectariferous and/or polleniferous species seems to be a reasonable management method to enhance the quantitative food niche on field margins and to support the conservation of pollinators in the areas surrounding farms.

Railway embankments - a refuge areas for food flora, and pollinators in agricultural landscape

Abstract In a modern agricultural landscape the assurance of food resources is a key issue in the maintaince and control of food niche for pollinators. In the present study we evaluated bee forage flora composition and diversity within railway embankments located in the agricultural landscape, SE Poland. We also analysed the abundance of pollinators that use food resources along railway embankments and recognized insect visitors preference for selected plant species. Railway embankments represent valuable refuge areas for bee forage flora (307 species, i.e. 76.1% of total flora) and pollinators (in total 4172 insect visits from 9 taxonomic groups). However, the richness and abundance of bee forage flora significantly differed between types of the railway distinguished by traffic volume. The highest diversity of bee forage flora is noted along the railway with intermediate traffic volume. Approx. 25% and 40% less bee forage species was identified along railways with low and high traffic volume. Likewise, bee forage flora differed considerably between microhabitat types, i.e. top vs. slope vs. bottom of the embankment. Providing support (e.g. mowing) seems to be an important management type in order to strengthen the native bee forage flora particularly on railway embankments along low and high traffic volume tracks. Such activity is crucial to counteract the spread of aggressive non-forage species (e.g. Calamagrostis epigejos, Artemisia vulgaris, Phragmites communis) and invasive species (e.g. Bunias orientalis, Solidago gigantea).

The effect of Agricultural Landscape Type on Field Margin Flora in South Eastern Poland

Abstract Plant species diversity is threatened in many agricultural landscapes due to the changes it has to undergo. Although the modification of the agricultural landscape pattern is observed across Europe, both extensive and intensive agricultural landscapes still co-exist in Poland. The objective of the study was to examine the flora in field margins in intensively and extensively managed agricultural landscapes, located across three regions in SE Poland. The flora was compared with respect to species richness, diversity, and evenness indices. Detrended correspondence analysis was employed to characterise variation in species composition. Agricultural landscape type made a higher contribution than the topography or geology to species richness and composition in field margins. Field margins function as important habitats for general vascular plant species diversity and are useful for the conservation of rare, threatened, endangered or bee plants. A significant decline in species diversity was observed over a distance of 1000 m from the habitat elements. Plants growing on field margins are mainly perennials; however participation of annuals clearly increases in intensive landscapes. The participation of wind-dispersed species decreased in an open-spaced intensive landscape. Animal-dispersed plants predominated in an extensive landscape with forest islands. Irrespective of landscape type, native species predominated. However, these habitats create the biota and corridors for alien-invasive species as well.

The habitat effect on the diversity of pollen resources in several Campanula spp. – an implication for pollinator conservation

Lack of pollen, a main protein source, is widely regarded as one of the causes of pollinator decline. This study investigated the potential mass of Campanula patula L., Campanula persicifolia L., Campanula glomerata L., Campanula bononiensis L., and Campanula trachelium L. pollen that can serve as food for insect visitors. Observations and measurements were made during the period 2006–2008 on two separate sites for each species (in natural or semi-natural vs. man-made habitats). The study site was situated in the agricultural landscape on the Lublin Upland, south-eastern Poland (51°18ʹ27ʹʹN, 22°26ʹ05ʹʹE). The total pollen yield was restricted by various biotic parameters (anther size and pollen viability) and abiotic factors (habitat and/or meteorological conditions). Therefore, the pollen production may differ considerably among species and the reward of the same species can be variable among habitats and growing seasons. The total pollen yield was higher on natural and semi-natural habitats (3.7–12.7 g per 10 m2 plot) compared to man-made habitats (2.9–4.8 g per 10 m2 plot). The main visiting insects are bees, although flies and beetles have also been recorded. Consequently, Campanula species are important in supporting general insect biodiversity within various ecosystems and indirectly influence pollination services and biocontrol in agroecosystems. To maximize the abundance and diversity of bees and other pollinators in the surroundings of agroecosystems, natural and semi-natural habitats with an adequate quantity of food supplementation, rather than man-made habitats, are indispensable. However, in the landscape context, the minimum size of high quality fragmented natural and semi-natural patches may differ considerably.

Validation of floral food resources for pollinators in agricultural landscape in SE Poland

BACKGROUND Proper management of bee pastures is considered an important activity for diversity of pollinators and conservation of the population size. In the present study, the floral composition and diversity, flowering spectrum and availability of food resources in natural and man-made habitats in four rural municipalities in Lublin Upland, SE Poland were evaluated. The connection between pollinator-friendly biotopes was also determined and some suggestions are made on creation/supplementation of bee pastures adapted to the arable land structure in eastern Poland (mean acreage 7.65 ha). RESULTS Forage species richness (S) differed among vegetation types: the highest S value was found in field margins, while mixed forests represented the lowest species richness (mean ± standard deviation = 37.8 ± 9.5 vs 16.5 ± 2.3). In all habitats, the most abundant flowering was recorded in May. Then the blooming abundance decreased until a complete decline at the end of summer. The mean distance between pollinator-friendly biotopes is 2.4 ± 1.53 km, which is out of the flying range/foraging distance of most pollinators. CONCLUSION Shortages of nectar and pollen resources in the agricultural landscape of SE Poland are evident. Therefore it is assumed that the landscape structure requires support in terms of food niches for pollinators and creation/supplementation of bee pastures is necessary, e.g. six to nine patches of 0.025-0.3 ha each within an area of 100 ha.

Availability of food resources for pollinators in three types of lowland meadows

The availability of floral resources is considered a key factor for the maintenance and conservation of pollinators. We compared the forage floral diversity of three types of lowland meadows (Molinia meadows, tall herb fringe meadows, and hay meadows) located in south eastern Poland. The total number of plant species was 125, including 84 species (67.2%) classified as plants visited by insects. The richness and diversity of forage flora differed between the types of meadow. The Molinia meadows and hay meadows were preferred by pollinators. However, different taxonomic groups of pollinators can respond to the variability and availability of floral resources in a different way. Molinia meadows are of particular importance for the abundance of Bombus spp., solitary bees, and flies. The RDA ordination model demonstrated that the floral community composition, plant species abundance, plant species richness, and floral attributes (size, shape, phenology) were all important for the abundance of insect visitors in the mosaic of meadows. The cluster analysis showed that most plant species were visited by similar groups of insects; however, their proportion differed considerably. Our results present arguments for inclusion of semi-natural meadows into conservation plans and for efforts of protection of highly effective floral resources aimed at maintenance of pollinators.

The impact of spatio-temporal changes in flora attributes and pollen availability on insect visitors in Lamiaceae species

Abstract There is growing evidence that food, in particular pollen, limitation is the strongest factor in pollinator decline. We have considered the potential effects of diversity in plant-community attributes as well as variations in the pollen and energy amount on the abundance and frequency of insect visitors to the Lamiaceae species Salvia pratensis L., S. verticillata L., Thymus serpyllum L., Betonica officinalis L. syn. Stachys officinalis (L.) Trevis., and Origanum vulgare L. The species were grown in two different habitat types (dry grassland vs. railway embankment) in the Lublin Upland, Poland. We found significant inter-species, inter-habitat, and inter-year disparities in the pollen mass and total energy amount per unit area. Canonical correspondence analysis (CCA) revealed that the blossom cover, species richness, and diversity noted at the plant community level significantly influenced the distribution of insect visitors to Lamiaceae species. The pollen caloric value and pollen abundance (but not the protein content in the pollen) had a considerable impact on the abundance and frequency of honeybees, bumblebees, and solitary bees in Lamiaceae flowers. Butterflies, beetles and flies did not respond to these factors. The model including all variables explained 66.4% of the observed variance. The studied Lamiaceae species, due to abundant flowering and good pollen nutritional value should be considered in the protocols to improve food resources, especially for social bees; however, disparities in pollen quantity and energy amount should not be ignored.

Factors responsible for the distribution of invasive plant species in the surroundings of railway areas. A case study from SE Poland

Abstract Invasive plant species are a growing concern in global biodiversity management. In this study, we tried to determine whether invasive plants could spread from railway track into the surrounding areas and focused on the factors responsible for the invasive plant species composition, richness, and abundance. We sampled invasive species along transects located outside a railway route and recorded the invasive species richness and abundance at a distance of < 5 (control), 5–10, 10–15, and > 15 m away from the railway edge in three geographical regions in SE Poland. We revealed that the mechanism allowing alien species to invade was complex. Canonical correspondence analysis (CCA) explained 30.9% of variance. On a regional scale, the invasive flora composition in the surroundings of railway habitats was determined by abiotic environment diversity (mean annual air temperature, mean annual precipitation), but not habitat-related factors (soil type, soil properties). On a spatial scale, the traffic volume, the distance from the railway area, the distance from build-up areas, and the interaction of these factors affect the invasive species composition away from railway areas. The invasive species spread from railways to the surrounding vegetation, therefore, regular monitoring of railway areas should be a framework for assessing the risk of invasive species.

Morphology of Anemone sylvestris L. flower (Ranunculaceae)

Abstract During the monitoring of populations of Anemone sylvestris L. (Ranunculaceae), a protected species in Poland, we found that the seed set is impaired. The flower is considered an adaptation that has coevolved to achieve effective pollination and successful fertilization. Therefore we have focused on the morphological and anatomical characteristics of the flowers of A. sylvestris L. as a prelude to the study of the species’ pollination biology and plant breeding system. The large size of the flower (50.6 ± 16.4 mm in dimensions) and its bowl shape fulfil both the biotic pollination syndrome and the aerodynamic requirements for pollen dispersal and capture. The opening and closing of the perianth provide a shelter for beetles. The odourless perianth, absence of nectar, scarcity of pollen (approximately 200 000 pollen grains per flower) and its traits - small size (axis P = 18.52 ± 1.0 μm; E = 16.59 ± 0.9 μm), lack of balsam on the exine surface, starch accumulation in more than 95% of pollen grains correspond to the specialization in anemophily. The stigma is papillous, the dense hairs are situated between single carpels indicating adaptation to capturing dry pollen and specialization in the wind pollination syndrome. The flower of A. sylvestris is an example for an intermediate form between entomophily and anemophily, i.e. a secondary and more advanced feature among Ranunculaceae.