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Determination of family size of beavers by camera-traps
Pivrnec, Ondřej ; Vorel, Aleš (advisor) ; Lenka, Lenka (referee)
This diploma thesis concerns the methodology and subsequent analysis of the quantity of European beaver (Castor fiber) inside a beaver family.
These data were collected by using camera-traps. Collection was conducted from August 2015 to August 2016 in two areas. The first area was the Czech forest and the second area was Šumava. In these areas is a different degree of saturation of the beaver population.
The main objective of this study was to estimate the average size of a beaver family in two model areas using camera-traps. Suitable areas were Czech Forest and Šumava. Secondary objective was to design and test methodology and application of the camera-traps and design a way to evaluate data from the captured images.
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Cranial variability of Centra European beaver populations
Oberreiterová, Veronika ; Vorel, Aleš (advisor) ; Korbelová, Jana (referee)
Abstract:
European beaver population in Central Europe originated from several refugial populations. Although these populations are currently well-researched, but the manifestations that may reflect genetic variability, are not known.
In the Czech Republic there are beavers who spread from Saxony, from Magdeburg refugia, and other stocks that are created by beavers from Austria and Bavaria, or are the offspring of individuals coming from refuges in Poland, Russia, Norway and France. There are many indications that individuals from northern Bohemia (Elbe individuals of the population) have a considerable amount of differences.
The aim of this study was to determine the exact age of mortalities beaver from the collection of the Department of Ecology FES. The most accurate estimate of the age is the closing of the basal opening of the tooth root and the sum of cement layers molars, but this method is time-consuming and technically challenging and therefore the work of trying to find another reliable criterion to determine the age of mortalities in the form of intervals of specific characteristics for each age class (juvenil, subadult, adult). Using statistical analysis, I conclude that the most cranial size determination for individuals age the length dimension is LCB (condyobasal length of the skull) and LAZ (zygomatic width of the skull). The most appropriate metristic characteristic to estimate the age appeared weight.
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Longterm analysis of beaver foraging - Do beavers sawing off the branch on which they are sitting?
Bartoň, Marian ; Vorel, Aleš (advisor) ; Jarmila, Jarmila (referee)
This thesis is focused on the analysis of eurasian beavers foraging behaviour and their strategy of getting food in the long-term perspective.
First part (theoretical) of the thesis contains an explanation of the theory of the central place foraging, animal selective behaviour when food is selected and central place foraging influence on trees fertility. In this part is also mentioned the predation risk or how does the beaver perceives competitive pressure from other animals, and factors that can cause the change in population density of beaver colonies. The objective of this work is to determine the effect of long-term beaver populating on the volume of comsumed biomass and expanse of the territory, and a comparison of these results with one another in terms of different times of occupated territories.
The second part describes the methodical procedure of the field survey. Data I collected from the areas of Šumava, Český les and South Moravia. I tried to find out, how the beaver´s foraging behaviour is induced depending on time inhabiting the territory and on increasing distance from the shore. This research shows that the beaver trips for food increases with age of occupation in 7-10 years and then the distance of tree cuts declined again from the shore. The volume of consumed biomass in reliance of increasing time of beaver occupation also decline and the most favoured tree species was an oak tree for which beavers were willing to walk long distances. The results of the simple analysis are presented as a measurement for both the entire region and also for each territory.
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Is the fur good predictor of intoxification of European beaver (Castor fiber) populations?
Faltová, Karolína ; Vorel, Aleš (advisor) ; Korbelová, Jana (referee)
This thesis deals with the burden of European beaver (Castor fiber) populations with risk elements in three areas of the Czech Republic and one area in Slovakia. There were investigated concentrations of heavy metals (Cd, Zn, Fe, Cu, Pb and As) in the kidneys, livers, lungs, hearts, muscles and fur of 19 found dead beaver individuals. Furthermore, their food was analysed to determine the contamination of their areas of origin and discover, which organ reflects the observed concentrations of Cd the best. The main aim of the study was to determine whether the analysis of hair could be used as a non-invasive method to reflect the concentrations of heavy metals in beaver populations in future. The results were conclusive only for As, whose concentrations in the hair was the second highest and correlated with the content of As in the lungs, which contained the highest concentrations of arsenic. Cadmium in the fur showed a reverse structure compared to the content of Cd in kidney and liver. There were found significant differences in the contamination with heavy metals between beaver populations and their environments. Analysis of the fur is not proved for most of the elements and it is necessary to investigate further non-invasive methods to determine the load of toxic elements on beaver populations.
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Reflects chemical communication of Eurasian beavers density-dependence?
Kovář, Jan ; Vorel, Aleš (advisor) ; Jakubíková, Lada (referee)
Reflects chemical communication of the Eurasian beavers density-dependence?
Almost all studies about population density describe certain dependency: with higher population density increased intensity of chemical communication. This is provided by many authors on different animal species. However this study showed that chemical communication does not reflects density-dependence of the Eurasian beaver. Explained variability of final model was r2 = 0.02586101, but with no significance for both variables. However some relationships were tested. Correlation between biomass (amount of consumed woody resources) and number of shelters (beaver nests) was not significant, but correlation between number of shelters and distance was positively significant. This lead to test the alternative special model (mc) where dependency of number of lodges and its changing distance was tested. This model was significant (p = 0.007182) and was discovered new relationship in population parameters of beaver populations: with increasing distance increased number of shelters.
Main focus of thesis was to study how the distribution and intensity of the chemical communication is related to parameters of population density. The result was: with increasing distance the intensity of chemical communication doesnt increase.
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