Comparison and integration of different techniques for the estimation of the minimum number of the brown bear (Ursus arctos, L.) in a peripheral and low density population

The north east of the alps (Friuli Venezia Giulia region) represents a peripheral area of the presence of the Dinaric population (for the north Dinaric population, 400-450 individual estimated) of the Brown Bear and in the last years some individuals from Trentino population (40-45 individuals estimated) have started to move to east and to use this areas. From 2004 to the 2013 in mountains areas of the Friuli Venezia Giulia has been studied (2000 km2) the presence of the Brown Bear with different techniques: the genetic sampling (by opportunistic and systematic methods), photo interpretation and behavioral analysis and radiotelemetry. The genetic samplings have been obtained by the hair traps (50 permanent hair traps plus 70 temporary and moving hair traps) and by opportunistic sampling. The success of the single hair traps have been studied in relation to the geomorphology and habitat characteristics and in respect to the year and season. The photos and videos (over 1000 samples considered) have been recorded, by infrared cameras (University of Udine and Regional Forestry Service, Hunters n=50), on the site of genetic monitoring and near the places of presence, like site of depredation or along the path. The video and photo has been analysed by Image J program to calculate some indexes derived from some measures of the head, body and color; the measures and indexes have been successively analyzed by multivariate analysis to distinguish different animals. The videos have been also analyzed to classify different behavior of the single animals. The classification with photo interpretation have been compared to classification obtained with genotyping. The success of the hair traps depends from the localization and habitat characteristics, with an evident effect of the year and season. The genetic analysis has detected the presence, from 2004, of 20 different genotypes (4 from Trentino 16 from the Slovenian population, 3 of them studied by telemetry), 15 of them in the last 3 years and 8 in the 2013; instead the analysis of photos and videos and behavior pattern has permitted to estimate the presence at least of 25 different individuals (11 in 2003). This fact confirmed that sometimes the hair traps are not useful because of the repeated use from the same individuals. Over the 70% of the hair sampling (with out any screening with photo and behavior analysis) obtained with the traps, comes from only 5 individuals. The phototrapping integrated to the hair traps can be useful to correct the minimum number of individuals and reduce the quantity of sampling to analyze. The choice of the location and distribution of the hair traps, integrated with photocameras and telemetry data, can reduce the research effort and can give some useful information on the ecology of the species.