Analyse van de reproductiviteit bij everzwijnen in Vlaanderen op basis van cameravalbeelden
De Clercq, F. (2022). Analyse van de reproductiviteit bij everzwijnen in Vlaanderen op basis van cameravalbeelden. MSc Thesis. KU Leuven, Faculteit Industriële Ingenieurswetenschappen: Leuven. 60 pp.
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Document type: Dissertation
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| Keywords |
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| Author keywords |
Sus scrofa, monitoring, litter size, MRAI, temporal variation |
| Abstract |
Wild boar numbers are rising across the whole of Europe. The same is true for the region of Flanders where increases in both quantity as distribution can be observed. This can be explained by the moderate climate and abundancy of food (mast and crops) which characterize the region of Flanders. However, this strong increment in population gives rise to wild boars causing human-wildlife conflicts. An example of this phenomenon are wild boars eliciting traffic accidents and causing damage to agricultural crops. Additionally, wild pigs are well-known vectors of many diseases such as African swine fever (ASF), which could cause great economic losses for livestock owners if transmitted to domestic pigs. Preceding issues are making clear that it is necessary to start monitoring the existing populations.Nonetheless there are no validated methods for doing so to date. There are, however, some methods that show promising results. One of these is the use of camera traps. In this master thesis attempts were made to create an image of the reproductive parameters of wild boar populations in the complex Meerdaalwoud-Heverleebos-Dijlevallei (MHD) and Hoge Kempen National Park (NPHK) during the years 2018-2021 and 2017-2021 respectively. The pictures, taken by the camera traps placed in both study areas, where processed using the Agouti platform whereby, among other things, the age of the observed animals was estimated. In this way it was possible to calculate the monthly relative abundance index (MRAI) of each age class over different years. Furthermore, efforts were made to determine the litter size and whether reproduction took place throughout the whole year.Our data showed that juveniles were the most-observed and second-most-observed age category in MHD and NPHK (not including the category with wild boars of which the age could not be determined). Subsequently, the results displayed that the populations in both areas had a whimsical structure whereby the shares of different age classes could fluctuate strongly each year. It was striking that the presence of juveniles peaked during late spring-summer (May-July) whereafter it reached a minimum during the winter months (November-February). The calculated average litter size turned out to be lower in comparison with the average litter sizes found in other European studies. This could be explained by the fact that other research papers calculated average litter size based on embryo counts and did not take the possibility of embryo loss during pregnancy and/or postnatal mortality into account. Though, when comparing our results with the hunting statistics -where an average litter size was calculated for each age class- we noticed that our results matched with the average litter size of juvenile sows.Furthermore, in 2021 in MHD, juvenile animals that clearly were of young age (recognisable by their small posture, longitudinal pale stripes and/or red fur) were additionally marked with the term of ‘pig’. As a result it was possible to detect that pigs were observed all year round. This could be a possible indication of the fading of seasonal reproduction.Previous shown results seem to point out that populations of wild boar in Flanders are characterised by a abundancy of juvenile animals, which possibly means that reproductivity is high. It is important to note that this master thesis only offers an explorative look in the use of camera traps. However, in doing so, it shows that camera trapping can be a useful asset in monitoring trends in population structure and reproductivity. |
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