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Od trusu k prostřenému ubrusu. Molekulární analýza potravy raka signálního
ŠKRABÁNEK, Jan
This thesis aimed to determine the diet of the signal crayfish in Křesánovský brook in 2020. In addition to that, we aimed to find and test suitable markers for the diet analysis of signal crayfish, which are described in the thesis. We analyzed the crayfish diet by examining DNA from faecal pellet samples collected monthly from April to September. By using group-specific DNA markers, we targeted the main dietary groups such as Heptagenidae (markers Hpt28Sf + Hpt28Sr), Ephemeroptera (Epa28Sf + Epa28Sr), Integripalpia and Spicipalpia (Inspi18Sf + Inspi18Sr), Plecoptera (Ple-gen A269 + Ple-gen S268), Chironomidae (Chiro18Sf + Chiro18Sr), and Gammaridae (Gamae28Sf + Gamae28Sr). We also focused on representatives of macrophytes Characeae (CHA677 + CHA1681R) and Eudicotyledons (MYR152F + MYR1696R). The results showed that the crayfish's diet varied during the sampling season. Gammaridae was the most common food item, found in 54.1% of the samples of faecal pellets. Heptagenidae, Integripalpia, and Spicipalpia were also significant, present in 31.3% of the samples. Plecoptera appeared in 20.8% of the samples, while Chironomidae and Characeae were found in 10.4%. Eudicotyledons were detected in 8.3% of the samples. Ephemeroptera were the least common food group, detected only in 2.1 %. Gammaridae were the most significant component of the crayfish diet in April (found in 7 samples), while Heptagenidae were the second most abundant component. The diet was more diverse in May, but Gammaridae remained the primary food source, followed by Integripalpia and Spicipalpia (in 5 samples). In June, Gammaridae was present in all samples, while Heptagenidae and Integripalpia/Spicipalpia were significant. In July, Heptagenidae was the most common food group (found in 5 samples), with Gammaridae found in 4 samples. No food items were detected in the samples from August and October, and only one sample contained Gammaridae in September. Overall, this study provides insights into both the seasonal variations in the diet of signal crayfish and markers suitable for its analysis.
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Alcathoe bat (Myotis alcathoe) in the Czech Republic: distributional status, roosting and feeding ecology
LUČAN, Radek
Between 2001 and 2008, we recorded Myotis alcathoe at nine sites within three distant areas in the Czech Republic. The species identification was confirmed with cyt b sequences and four distinct haplotypes were identified. All the localities exhibit surprisingly uniform habitat characteristics: (1) old full-grown oak-hornbeam forests, with (2) numerous large trees in advanced stages of decay are present, and (3) a very small to large water bodies and/or patches of riparian vegetation surrounded by the forest. Using radiotracking techniques, we discovered 27 day roosts of M. alcathoe, located mostly in big oak, birch and lime trees inside extensive forest stands. All roosts were fissures or small cavities in a tree trunk and in branches in the canopies, some 16 m above the ground. Bats preferred trees that were higher, had higher canopy and canopy basement and had larger diameter at breast height than other available trees. Roost trees were surrounded by lower trees with lower canopy basements than available trees. Roost trees were in a poorer condition than other available trees. Roosts were occupied by up to 83 individuals in July but usually single individuals were found in the roosts in September. In contrast to syntopic M. mystacinus and M. brandtii, M. alcathoe has never been found in an anthropogenic roost (except for a fissure in concrete electricity pole). Preliminary analysis of the diet showed that nematoceran flies were the most important prey item along with spiders, caddis flies, small moths and neuropterans. In the observed ecological characteristics, M. alcathoe markedly differs from other European species of the genus Myotis. Its restricted habitat requirements are perhaps responsible for an islet-like pattern of its distribution and suggest an essential conservation value of the habitats of its occurrence.
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