The invasion and spread of non-native species of many different kinds of organisms is of increasing interest to researchers. Invasions by microscopic organisms, however, are poorly understood, and their impact on the environment is probably underestimated. We collected available data on nonnative and invasive/expansive algae and cyanobacteria in the Czech Republic; we mapped their distribution and assessed their impact on local species and other real or potential risks resulting from their spread. The list of alien species in the Czech Republic contains 10 species of cyanobacteria, 9 species of Bacillariophyceae, 1 species of Dinophyta, 1 species of Ulvophyceae, 2 species of Chlorophyceae, and 1 species complex of Zygnematopyceae. The literature on the worldwide occurrence of these taxa is also reviewed.

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Domestic gardens supply pollinators with valuable habitats, but the risk of exposure to pesticides has been little investigated. Artificial nesting shelters of a red mason bee species (Osmia bicornis) were placed in two suburban gardens and two commercial fruit orchards to determine the contamination of forage sources by pesticides. Larval pollen provisions were collected from a total of 14 nests. They consisted mainly of pollen from oaks (65–100% weight/sample), Brassicaceae (≤34% w/s) and fruit trees (≤1.6% w/s). Overall, 30 pesticides were detected and each sample contained a mixture of 11–21 pesticide residues. The pesticide residues were significantly lower in garden samples than in orchard samples. The difference was attributed mainly to the abundant fungicides pyrimethanil and boscalid, which were sprayed in fruit orchards and were present on average at 1004 ppb and 648 ppb in orchard samples, respectively. The results suggested that pollinators can benefit from domestic gardens by foraging from floral sources less contaminated by pesticides than in adjacent croplands.

Palaeolimnological reconstruction of the aquatic environment in Lake Komořany, based on sedimentology, geochemistry, and diatom and macrofossil analyses in the littoral part of the basin, reflects the mid‐Holocene history of the profile from its origin c. 9100 cal. a BP to its final transformation into an alder carr c. 4100 cal. a BP. The existence of the littoral zone can be best explained by increased precipitation during the studied interval. A stable diatom community, diatom‐inferred total phosphorus (50–80 μg L−1) and pH (~7.6), along with stable concentrations of elements associated with changes in its watershed indicate a long‐lasting, balanced aquatic environment with no major shifts attributable to external factors, including climate change. From c. 4700 cal. BP, there started a transition to terrestrial conditions, caused by either natural infilling processes or decreased precipitation. Alternation of remarkable dry/wet phases was not detected, in contrast to numerous analogous central European and supraregional records. Potential human impact was revealed through increases of Corylus and Populus pollen in the Neolithic. These anthropogenic changes in the lake surroundings had no detectable influence on the lacustrine environment. The gathered data suggest undramatic, balanced mid‐Holocene environmental and climatic settings for this central European locality, in direct contrast to numerous analogous studies from the region emphasizing fluctuations and shifts found in the sediment record.