Fine-scale genetic structure suggests low levels of short-range gene flow in a wolf population of the Italian Apennines

Abstract

International audienceWe investigated local gene flow in a high-density wolf () population of the Italian Apennines, where no effective barrier to wolf dispersal was present. From 1998 to 2004 we examined wolf carcasses and non-invasively collected samples, focusing on three mountain districts, separated by two valleys, where wolf packs showed high spatial stability. Using nine autosomal microsatellites we successfully genotyped 177 samples, achieving the identification of 74 wolves. Genetic relatedness steeply decreased with increasing distance between sampling areas, thus suggesting that short-distance interpack migration is infrequent in this population. In addition, no individual from a central pack under intensive monitoring was sampled in the range of the surrounding packs over a 4-year period. The limited short-distance gene flow resulted in a cryptic genetic structure, which was revealed by Bayesian analysis. A different genetic cluster was found in each of the three mountain areas, and a small proportion of first-generation immigrants was detected. Overall, the present study suggests that local genetic differentiation in Italian wolves might arise from high spatial stability of packs and can be favoured by a combination of long-range dispersal, the attitude to mate between unrelated individuals and a high young mortality rate

An improved procedure to estimate wolf abundance using non-invasive genetic sampling and capture–recapture mixture models

“…Moreover, in winter the detection probability is not so dependent on the social role of individuals, because on the snow it is possible to find scats of all individuals of a pack (Mech and Boitani 2003). Additionally, weakly detected individuals showed an annual survival rate (0.66) significantly less than highly detected individuals (0.75), which could be explained by the higher mortality of pups and yearlings (Chapron et al 2003;Mech and Boitani 2003;Scandura et al 2011). These estimates are concordant with wolf survival rates in the western French Alps (Cubaynes et al 2010).…”

“…The P L individuals (low capturability) showing higher detection probability in winter, could be pups, yearlings and subordinates, whose winter survival is usually much higher than during spring and summer, and that can be sampled only after the breeding period, or migrants that can generally disperse after the winter, about 10 months after their births (Fuller 1989;Boyd and Pletscher 1999;Chapron et al 2003;Mech and Boitani 2003;Marucco et al 2009). This hypothesis is further confirmed by the high percentage (64%) of carcasses belonging to previously unsampled individuals, and concurs with data about wolf mortality already reported in the northern Apennines (Scandura et al 2011). In contrast, the P H individuals (high capturability), corresponding to individuals detected throughout all the year, could be territorial adults and dominants that frequently mark their home ranges (Vila et al 1994;Mech and Boitani 2003).…”

Efficient, Noninvasive Genetic Sampling for Monitoring Reintroduced Wolves

“…The wolf is the only large carnivore in the area, otherwise populated by wild ungulates such as the ubiquitous wild boar Sus scrofa and roe deer Capreolus capreolus, plus a limited number of red deer Cervus elaphus. Wolf presence in this area has been monitored since 1998, through summer sessions of wolf howling (Passilongo et al 2010), NGS (Scandura et al 2011) and, more recently, CT. In recent years, signatures of wolf-dog hybridization were detected in carcasses and non-invasively genotyped individuals (Iacolina et al 2010, Bassi et al 2017.…”

“…In the last decade, these methods have been adopted to assist in the management of the gray wolf Canis lupus in many regions (Stenglein et al 2010, Bohling and Waits 2011, Randi 2011, Scandura et al 2011, Caniglia et al 2012, Cohen et al 2013, Ražen et al 2016, Subba et al 2017. Despite their wide application, though, both methods have limitations.…”

One, no one, or one hundred thousand: how many wolves are there currently in Italy?

“…Short-time monitoring projects often used heterogeneous methods, producing data that are difficult to aggregate in coherent sets (Apollonio et al 2004;Fabbri et al 2007;Scandura et al 2011;Marucco and Boitani 2012). As a result, a comprehensive overview of the current population status at the national scale is still lacking, with the most recent population estimate tracing back to the 1970s (Zimen and Boitani 1975).…”