The european wildcat (felis silvestris silvestris) : study for a functional method of population research

Abstract

The wildcat is one of the most elusive mammalian carnivores in Italy. It is a species protected by the EC (Habitat Directive) and the efforts for its conservation are strictly related to a sound knowledge of its population parameters and genetic status. The different biological, genetic, taxonomic, phylogeographic and legal issues related to this species should all be considered in order to get to correct conclusions about its conservation status and the actions that should be applied. In this context I carried out my PhD thesis which has been developed through the collaboration between the Science Department of Roma Tre University, the Foreste Casentinesi National Park and the conservation genetics laboratory of ISPRA in Ozzano dell’ Emilia. This work took into account three main objectives : 1. Evaluate a standardized integrated protocol for non-invasive monitoring applying a methodology that integrating the different non-invasive techniques allowed us to improve the collection of diversified data (genetic, ecological, ethological, photographic, etc. ..) exploiting the least possible sampling effort. In this work we developed a protocol in which the sampling campaign was stratified simultaneously into three different layers: the camera-trapping layer, the scat-surveying and the hair-traps sprayed with valerian tincture (Valeriana officinalis). Using this method we were able to associate the genetic datum to the photographic one, identifying wildcats individuals, detecting hybridization traces, assessing the invasiveness of domestic cats and studying the reactions to the attractor. Alongside it was possible also to take advantage of the versatility of the camera-trapping in order to observe some aspects of the wildcat behaviour and the relationships with some potential competitors. This protocol has been chosen by the Biodiversity Department of the State Forestry Corps operating in the Foreste Casentinesi National Park as a tool for investigating the European wildcat in the integral Natural Reserve of Sasso Fratino. 2. Study more efficient genetic markers for assessing admixture and introgression between wildcat and domestic cat. In the second section, taking advantage of a fruitful collaboration with a ISPRA researcher, we performed a wide genetic investigation of novel loci to establish a set of diagnostic tools suitable for accurately detect levels of introgressive hybridization between European wildcats and domestic cats. 150 samples (including putative European wildcats, captive and putative hybrids and domestic cats) from 15 different European countries and previously analysed at 31 microsatellites loci were analysed with an Illumina Infinium iSelect 63K Cat DNA Array from which SNPs were selected the 151 most informative. Results from Bayesian model-based computations of simulated and empiric genotypes showed that the entire set of 151 markers provided successful estimates of admixture, correctly assigning all parental, F1-F2 hybrids and first and second generation backcrosses. A direct comparison between most informative SNPs and STRs proved the outperforming power of SNPs on admixture detection and inferring admixed ancestries. To increase the temporal depth of such analysis and check for a possible hidden introgression were also analysed a total of 1269 bp of mtDNA (a coding portion of ND5 containing 7 putative diagnostic mutation and the Region of Control) and two markers on the Y chromosome (SMCY STR-7 and a SNP on the SRY gene). These markers allowed us to draw a phylogenetic history of the samples from which emerged two possible different transmission events that led to a mitochondrial haplotypes sharing between the wild and domestic population opening the way for further studies to better understand the phenomenon. Results were organized in a manuscript that is currently under preparation: 3. Clarify the phylogeographic history of the species in Europe. The second work mentioned above has shown how different haplotypes characterized by typical domestic polymorphisms appeared with good frequency in the wild population. So in this last one part we provided the preliminary results of a phylogenetic and phylogeographic analysis sequencing 669 bp of the subunit 5 of NADH dehydrogenase of 717 samples of European wildcats, domestic cats and putative hybrids collected from 14 different locations in Europe previously analysed using 31 microsatellite loci. In this work, we have deepened the phylogeography of wildcat in Europe and shed light on the causes that led to the cytonuclear discordance on several individuals. Further analyses are underway for the definition of effective sample size and migration rates between the groups identified In conclusion, this work aimed to propose a multidisciplinary approach to deal with the problems of conservation of the wildcat defining the most efficient and standardized tools possible that could mediate a reasonable operational effort with a high quantity and quality of data.