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Towards a better understanding of ungulate diets: a methodological approach
Holá, Michaela ; Červený, Jaroslav (advisor) ; Stádník, Luděk (referee)
Populations of European ungulates have grown substantially over recent decades, resulting in considerable environmental and socio-economic impacts. Availability and quality of natural and supplemental food sources are among the main factors driving their population dynamics. Detailed knowledge of feeding strategies of management-targeted species is therefore of primary importance for their successful management. Over time, methods to study the feeding strategies of animals have also evolved considerably but each has its advantages as well as limitations. This doctoral thesis uses a combination of traditional methods (i.e. stomach content analysis) and novel methods (i.e. stable isotope analysis, near infrared reflectance spectroscopy) to achieve a better understanding of feeding strategies of two important ungulate species (i.e. wild boar and red deer) in the Czech Republic, where their populations are on the rise and supplementary feeding is rampant. Next, this dissertation aims to introduce and to establish a basis for these novel methodological approaches for the study of free-ranging individuals. In this respect, it also addresses methodological issues related to their application in this field.
The diet composition of wild boar was investigated by examining stomach contents in order to identify their dependence on food resources of human origin (i.e. agricultural crops and supplemental foods). Foods of human origin were the dominant diet type and constituted the bulk of the diet of wild boar throughout the year. A necessary prerequisite for application of stable isotope analysis is the trophic discrimination factor (i.e. systematic difference between the isotopic composition of the consumer tissues and that of the diet), which was experimentally determined for stable carbon and nitrogen isotopes, the two most commonly used in ecology, in hair tissue of wild boar and red deer. Furthermore, possible sources of variation (such as sex, age, body weight, and lactation) on isotopic discrimination were investigated. The results of the experiments provide a starting point for the successful use of stable isotope analysis in field studies on wild boar and red deer. Finally, application of near infrared reflectance spectroscopy was proven to be useful in measuring faecal indices of food quality for red deer. The results of this thesis will contribute towards efficient management of wild boar and red deer in the Czech Republic.
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