Claudio Prigioni

ESTIMATION OF EUROPEAN OTTER (LUTRA LUTRA) POPULATION SIZE BY FECAL DNA TYPING IN SOUTHERN ITALY

Abstract Population size of European otters (Lutra lutra) was estimated in Pollino National Park (southern Italy) by genetic typing of fresh feces collected in the field. Of 187 fecal samples gathered, 185 (98.9%) yielded otter DNA, 77 (41.2%) were successfully typed, and 23 different genotypes were identified. A nonlinear regression between the number of typed spraints and the cumulative number of identified genotypes was repeated after randomization of the sample until it gave an estimated otter population of 34–37 animals (0.18–0.20 otters/km of watercourse). The applied method represents a valuable conservation tool, combining the advantages of an indirect survey with the accuracy of an exhaustive census.

Altitudinal gradient of Eurasian otter (Lutra lutra) food niche in Mediterranean habitats

The effects of geographical factors, such as latitude and altitude, on climate are known to influence the food habits of predator species distributed over a broad distribution range. A sharp latitudinal gradient in the diet of the Eurasian otter (Lutra lutra (L., 1758)), that is an increase of trophic diversity from temperate to Mediterranean Europe, has been described recently. Altitude, affecting the diversity of fish assemblages and hence prey availability for otters, could also be a key factor influencing otter diet. With the aim of testing for the presence of an altitudinal gradient in otter diet in the Mediterranean area, we assessed the composition of diet at 24 sampling reaches spread in three main river catchments of southern Italy. The analysis of 1885 spraints revealed that fish were the main prey of otters, followed by amphibians, while other food items were of lesser significance, although crustaceans could be locally important. The altitude of the sampling station was negatively correlated w...

Food habits of genetically identified pine marten (Martes martes) expanding in agricultural lowlands (NW Italy)

We assessed the diet of pine marten (Martes martes) expanding in the heavily human-altered agricultural plain of the River Po, northern Italy. Between February 2008 and November 2009, surveys were carried out twice a week during seasonal sampling sessions of three to four consecutive weeks. To distinguish the faecal samples from those of sympatric carnivores, a polymerase chain reaction-restriction fragment length polymorphism method was applied. The availability of small mammals was assessed by the analysis of 59 barn owl (Tyto alba) pellets. A total of 109 pine marten faeces were analysed. Its diet consisted of fruit, rodents, lagomorphs and birds. Seasonal variation occurred for fruit, which prevailed in summer, and rodents, which were more preyed upon in autumn. In winter, the diet of the pine marten was almost totally based on vertebrates, and lagomorphs were the main source of protein in summer. Use of small mammals differed significantly from their availability, voles, particularly bank vole Myodes glareolus, being preferred to mice (Apodemus sp.) and rats (Rattus sp.). Medium-size mammals formed about 18% of pine marten diet, a value generally reported for high-latitude habitats. In agricultural areas, the pine marten proved to be an opportunistic predator, able to face the reduced availability of small mammals by preying upon medium-size prey and fruit.

Distribution and sprainting activity of the Otter (Lutra lutra) in the Pollino National Park (southern Italy)

From March 2001 to December 2002, 32 stretches (sampling stations, mean length 673 m) distributed on 17 watercourses of the Pollino National Park (southern Italy) and the surrounding area were searched monthly for otter Lutra lutra signs, mainly spraints. All the watercourses were positive for otter with a mean percentage of 82.2%, indicating a stable presence of otters, mainly on Sinni and Mercure-Lao catchments (central-northern part of the park). Mean sprainting activity was 12.8 sprainting sites/km and 31.7 spraints/km, and showed a seasonal variation only in 2001 with two peaks, in May-June and in October. Sprainting activity was positively correlated with the percentage of positive stretches on watercourses, confirming that spraint density can represent an indicator of the population size of otters. A preliminary evaluation of the relationship between fish availability and otter marking intensity was performed along 39 km of the River Sinni on one day. A positive correlation was found between sprainting intensity (spraints/km) and the number of suitable sites for fish, such as pools or stretches of streams with good vegetation cover. Sprainting activity seemed to be linked to the distribution of fish availability. Since the Pollino National Park occupies a strategic position within the Italian otter range, an accurate management plan is needed to improve the quality of riverine ecosystems and to conserve otters.

Differential use of food and habitat by sympatric carnivores in the eastern Italian Alps

In an Alpine area, scat analysis and marking activity were used to assess the feeding habits, habitat preference and the degree of overlap of trophic niche and habitat use in sympatric carnivores: the red fox (n = 133 faecal samples), the badger (n = 177), the pine and the stone marten (Martes sp., n = 382). Fruits were the main trophic resource for all species. The diet of martens differed from those of the red fox and badger by means of a higher consumption of garbage and non‐Rosaceae fruits. The red fox preyed on more lagomorphs and roe deer and relied almost exclusively on two fruit species, rose‐hips and whitebeam berries. Badgers ate few invertebrates, with cultivated fruits and pine seeds forming the bulk of their diet. On the whole, trophic niche overlap was kept low by the exploitation of different species of berries and mammals and, secondly, by seasonal differences in the use of same items by the three carnivores. Badger trophic niche overlapped to a wider extent than those of the other two predators in summer, when fruit availability is higher. Foxes used all habitats according to their availability, except for villages, which were avoided. Badgers used mainly open habitats, particularly Alpine meadows, avoiding villages and mixed woods. Martens selected the habitats avoided by the other two predators and avoided all the others. The narrow range of habitat used by martens and diet evidence suggest that, within the context of interspecific competition, they could play the role of sub‐ordinate species, segregating in fox‐free urban environments.

The otter Lutra lutra in Albania

Abstract During a survey in Albania we found signs of otters at 17 (54·8%) of the 31 stations investigated. Otters were widespread in much of the country, and healthy populations were localised in rivers and marshes in the north-west and in the south. Average sprainting activity was 1·7 positive sites per 200 m and 3–6 spraints per 200 m. Frogs, probably Rana ridibunda , as well as fish, appeared to be important prey for otters. In the coastal plains, several rivers were grossly polluted and the growing agricultural and industrial development may endanger the survival of otters.

Percentage of protein, lipids, and carbohydrates in the diet of badger (Meles meles) populations across Europe

Although originally evolved as predators, several species of mammalian carnivores exhibit a great trophic diversity, ranging from hypercarnivory to a high consumption of vegetable food. Habitat characteristics influence food availability and consequently could affect the nutritional composition of the diet of generalist species. By reviewing the available literature, we tested the hypothesis that intraspecific differences in the food habits of badgers (Meles meles) living in different habitats across Europe could affect the percentage of macronutrients (i.e., protein, lipids, and carbohydrates) in their diet. Notwithstanding the different composition of the diet, the percentage of protein and lipids fed by badgers did not vary among temperate forest-pasture mosaics, Mediterranean woodlands, or scrublands and arable lands, suggesting a certain form of regulation of the diet balance. The percentage of carbohydrates was similar in the first two habitats, while it was fivefold higher in arable lands, where cereals were the main food of badgers and were consumed throughout the year. Earthworm consumption by badgers was positively related to the latitude, while the lack of any latitudinal or altitudinal pattern in protein consumption reflected the absence of a gradient in carnivory. A slight inverse latitudinal gradient in lipids consumption probably depended on the use, in southern Europe, of vegetal foods rich in lipids. We hypothesize that in agricultural landscapes dominated by crop cultivations, the decline of animal prey (i.e., earthworms, insects, and vertebrates) due to habitat loss forced badgers to increase the percentage of protein in their diet by over-eating cereals, with the consequence of a disproportionate increase in carbohydrate consumption.

Scent Marking of Key Food Sources in the Eurasian Otter

In the context of intraspecific competition, the distribution of key resources within a territory could influence the spatial patterns of scent deposition by territory owners, in order to maximise the defensibility of resources and reduce the costs of their defence. We investigated the pattern of spraint deposition by the Eurasian otter (Lutra lutra) in Mediterranean rivers of southern Italy, testing the hypothesis that spraints are concentrated around deep pools bordered by riparian vegetation because these represent important patchy sources of food. Otters strongly selected pools throughout the year, marking the largest ones which probably supported the highest fish biomass. Sprainting sites at pools were also marked more consistently than sites elsewhere on watercourses. A positive correlation between the percentage of spraints next to pools (pool markings) and overall volume of the main prey in otter diet confirmed the importance of pools as sources of prey. These results are consistent with the idea that territory owners should concentrate scent marks on key resources, as an adaptation to the constraints of defending long and narrow territories, which follow the shape of the rivers. Pool marking increased in the warm season and in December–January, but was not correlated with monthly consumption of the main prey, raising the hypothesis of an additional, reproductive function of scent marking. In the absence of specific data on reproduction or births in our study area, this hypothesis needs further investigation.

Feeding ecology of Leuciscus cephalus and Rutilus rubilio in southern Italy

The diet and feeding relationships of two cyprinids, the Italian orange‐fin roach Rutilus rubilio and the chub Leuciscus cephalus, were studied in southern Italy by the analysis of 189 gut contents. Fish species were sampled in conditions of sympatry/hybridisation in the River Sinni, and allopatry in the River Mercure‐Lao (roach) and in the River Raganello (chub). The diet of both fish species included both plant material and invertebrates. The broad spectrum of prey eaten showed that both fish species looked for invertebrates along the whole water column and particularly on the surface. For the River Sinni a high dietary overlap was found. The high contribution of plant material in the overall diet of roach in the presence of other cyprinids species, compared with the almost equal importance of plant material and animal food in allopatry, suggested that competition could be the cause of roach dietary shift towards suboptimal food sources. For the river Raganello, the high proportion of vegetation in the diet of chub, compared to the River Sinni, was explained as a consequence of habitat degradation caused by anthropogenic activities. Our results confirmed the generalist and opportunistic foraging behaviour of both fish species.

Range of the Eurasian badger (Meles meles) in an agricultural area of northern Italy

From June 2000 to December 2003 a low-density badger (Meles meles) population was studied by radiotelemetry in an area of agricultural lowland in northern Italy. Four badgers, one male (M1) and three females (F1, F2, F3) were caught but only three of these were radio-tracked for 8–12 months because the transmitter attached to F3 failed. Tracked animals showed considerable home range overlap, with an overall mean size of 3.83 km2 (M1 = 3.22 km2, F1 = 2.39 km2, F2 = 5.87 km2, Minimum Convex Polygon of 100% of the locations). In the study area 10 setts (mean number of entrances = 2.1) were detected. Each radio-collared badger used 2–3 setts, occupying one sett from 1 to 8 months (mean = 3.7 months, SD = 3.06) before moving to another one. All badgers shared, although in different periods, one main sett located in the inner part of their ranges. Considering this evidence and additional data about badger translocation from neighbouring areas, the social structure badgers in northern Italy is discussed.