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Possible solutions to the restoration of overmature forest stands in the Lány game enclosuregame-park
Ambrož, Robin ; Vacek, Stanislav (advisor) ; Igor, Igor (referee)
Possible solutions to the restoration of overmature forest stands in the Lány game enclosure -- this is a problem that generations of foresters in the Křivoklátsko region have been faced with. The restoration has often been postponed; as a result, there has been a remarkable increase in the number of such stands in the game enclosure. Currently, almost a third of the game enclosure is covered by stands, predominantly beech, older than 160 years, and the suggestions on how to restore these stands are by no means unified, not only within the framework of the relevant authorities, but also among the management of the Lány forestry administration. In the past, the disintegration of stands in the highest age class was dealt with by a massive planting of large-sized plants in the whole area of the game enclosure, which has brought and will continue to bring about a remarkable increase in the forest protection costs. The aim of this PhD thesis is to answer the questions concerning the restoration of the local beech stands and to propose a solution that would be efficient in the long term. The basic questions have been phrased as follows: In what condition are the extensive large-sized plant plantings? What is the number of overmature forest stands in the Lány game enclosure and what will their future development be? Are these stands still capable of producing a sufficient number of beech seeds to ensure successful natural regeneration? In what way should we restore these overmature forest stands? How should we protect them from the game damage? It was necessary to find some of the answers within the framework of intermediate scientific tasks; however, the finding of a conceptual solution to the restoration of the game enclosure remained the main goal of this work. To fulfil the goals of this thesis, it was necessary to perform the inventory of large-sized plant plots; it was found out that the total number of individuals planted in the Lány game enclosure until the end of 2011 was 28,994 at 840 plots. The plantings established in 2011 were surveyed as to their vitality and height increment between the years 2011 and 2014. In 2015, a sample was selected on which the condition of the root system was analysed according to the type of a container used for the raising of large-sized plants. It is evident from the results that despite considerable investment in fencing, the large-sized plant plantings are very often damaged by game and have to be repeatedly reinforced. The root system analysis revealed that a significant number of individuals show serious root system deformations. Consequently, the optimization of large-sized plant planting was proposed. The condition of the beech stands at PRP was ascertained with the aid of the FieldMap technology; the stand development prediction was carried out by the growth simulator SIBYLA. The verification of the fertility of the overmature beech stands took place at smaller plots demarcated within PRP. The results show that the occurrence of game eliminates natural regeneration in these stands; thus, it is necessary to find a way which will not be only efficient, but also economical. The fertility verification proved that despite their advanced age, the beech stands preserve their ability to produce seed material, which could be used for regeneration under a shelterwood. Finally, a model regeneration block presenting two possible reproduction methods (with maximum utilization of natural regeneration and accelerated one) was designed on the basis of both the differentiation of the game enclosure and the localization of stands with the highest degree of regeneration urgency.
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Molecular genetic characterization of vancomycin-resistant enterococci
Bubeníček, Karel ; Rada, Vojtěch (advisor) ; Igor, Igor (referee)
Summary
Objectives and hypothesis: This thesis concerns the study of plasmids of vancomycin-
resistant enterococci isolated from feces of American crows in the years 2012 - 2013 period.
The hypothesis is that, in various environments, there is one or more types of
epidemiologically significant vanA gene-carrying plasmids that are capable of horizontally
spread.
Methods: Based on PFGE method the number and size of plasmids were detected in selected
isolates of vancomycin-resistant E. faecium. Using PCR method the isolates were subjected
to detection of genes of replicases, relaxases and toxin-antitoxin system of plasmid-bound
resistance genes. Using 19 primers were characterized types of Tn1546.
Results: Of the 12 tested vancomycin-resistant isolates of E. faecium the following number
and size of plasmids was proven using PFGE method: 2 isolates contained two plasmids
(17%), 3 isolates contained three plasmids (25 %), 5 isolates contained four plasmids (42 %)
and 2 isolates contained five plasmids (17 %).
All isolates (n = 12) were then subjected to the detection of genes of replicases, relaxases and
toxin-antitoxin system for typing of plasmids from each plasmid families.
RepA_N family of plasmids:
genes characterizing plasmids related to pRUM: rep17 in 11 isolates (92 %),
gene Axe-Txe was detected in 5 isolates (42 %)
genes characterizing plasmids related to pLG1: rep20 in 7 isolates (58 %)
genes characterizing plasmids related to pAD1: relpAD1 gene was detected in one isolate (8 %)
Inc18 family of plasmids:
genes characterizing plasmids related to pIL501: rep1 gene detected in one case (8 %)
genes characterizing plasmids related to pRES25: rep2 gene in 2 isolates (17 %)
genes characterizing plasmids related to pEF1: relpEF1 detected in 11 isolates (92 %)
pHTB family of plasmids:
genes characterizing plasmids related to pHTB: rep22 gene was detected in 4 isolates (33%) and in 2 isolates gene relpHTB was detected (17%)
RCR family of plasmids:
genes characterizing plasmids related to pRI: positive detection of Rep14 gene in 8 isolates (67%) and in 4 isolates relpRI gene was detected
Small theta-replicating plasmids:
genes characterizing plasmids related to pEF418 plasmids: rep18a gene in 2 isolates (17%)
genes characterizing plasmids related to pB82: rep18b gene was detected in one isolate (8%)
genes characterizing plasmids related to pCIZ2: relpCIZ2 gene was detected in 9 isolates tested (75%)
Types of transposon Tn1546
Using the PCR method types of Tn1546 were characterized. In 4 isolates (n = 12; 33 %)
Tn1546 was characterized as a F3 type. In one isolate (8 %) Tn1546 was characterized as a
type F5, in one isolate (8 %) as a type PP-16. In 6 isolates Tn1546 was untypeable. Most
likely these are new, yet unknown types.
Conclusion: This is the first study of plasmids of vancomycin-resistant isolates E. faecium
isolated from feces of American crows. These results emphasize not only a high proportion of
plasmids in individual isolates, but also a high proportion of genes with horizontal transfer.
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