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Oxbow lakes are specialised standing water bodies that often support unique macrophyte and animal communities. Between 2015 and 2016, we assessed the diet composition of adult rudd (Scardinius erythrophthalmus) in one such macrophyte-rich lake. Over 2016, we also undertook a series of feeding behaviour tests under artificial conditions, the aim being to assess whether adult rudd represent a threat to the endangered sharp-leaved pondweed (Potamogeton acutifolius). In total, we examined 100 digestive tracts of rudd feeding under natural conditions and 100 from rudd feeding under artificial conditions. Our results show that i) P. acutifolius is deliberately consumed by rudd, and ii) pondweeds, periphyton and invertebrates were the dominant dietary components in the diet. A reluctance to consume cleaned P. acutifolius suggests a link with periphyton and invertebrate consumption. While rudd clearly consume P. acutifolius, we found no evidence of any negative impact on either pondweed development or on the macrophyte community as a whole.
In the last decades European roe deer (Capreolus capreolus) expanded its range, recolonizing also highly anthropized areas. In northern Italy this species recently reached the Po Plain, suggesting the possibility for the future settlement of a metapopulation in the whole plain. In this process, a key role may be played by internal source areas, such as Ticino Natural Park, where roe deer was reintroduced in 1990s. We carried out drive counts and surveys in a sample area of Ticino NP, in order to investigate about the current status of this population. Population Viability Analysis (PVA) was applied to infer about the population viability and its potentiality as source for dispersals. Our results showed a high-density population (30.7 ± 4.1 individuals per km2), with quite low proportion of juveniles (10.7 %), litter size (1.35 fawns/mother) and proportion of successful breeding females (24.6 %). Considering the high density of this population, its low productivity is most likely due to the onset of density-dependent factors and the approach to the carrying capacity. Neverthless, the PVA showed that in the next 30 years this population is likely to remain viable, representing an important potential source for a roe deer expansion in the fragmented lowland area of northern Italy.
A water vole Arvicola amphibius population inhabiting midfield ponds was studied by live-trapping, radio-telemetry and with camera traps. Within the midfield ponds, water voles did not prefer any particular type of littoral vegetation and avoided open water areas within the ponds. The mean distance of daily movements was 118 m for males and 53 m for females. The maximum distance between two locations of a radio-tracked individual within its home range during the whole study period was 450 m. Water vole movements between the studied ponds were very limited. Most of the hiding places were located in the areas around ponds. Water voles were active mostly during the night.
Invasive alien species, once introduced, may affect local biodiversity, both directly (e.g. by predation) and indirectly (e.g. by reducing the vegetation cover). Among those, rats (Rodentia, Muridae) are listed among the most invasive species, exerting strong impacts particularly when introduced to island ecosystems. Accordingly, black rats Rattus rattus have been eradicated from a number of islands in the Mediterranean basin to protect breeding seabirds. Where the larger Norway rat Rattus norvegicus is present, extent of damage may be even higher. In our work, we present the results of the first eradication program dealing with Norway rats in a small Mediterranean island (Isola delle Femmine, Sicily, Southern Italy). The eradication took place in 2007-2008 and, since then, no rat has been observed on the island, thus proving the success of the management action. Vegetal cover increased on the island after rat eradication. Furthermore, the Sardinian warbler and the blackbird started to breed on the island.
A study on group size and composition in Siberian ibex (Capra sibirica) was conducted in the Eastern Tien-Shan Mountains. We found that small groups (1-5 individuals) were most common for this species. Generally, mixed-sex groups were larger than male and female groups. Since males have more ability for fiber digestion, because of their larger body size than females, they are less selective in food quality. Due to this, males gathered into larger single-sex groups in August-September, when forage was at its maximal biomass, and into smaller groups when the amount of food was limited (winter-early-spring). During birthing period, pregnant females typically separated from groups to give birth, returning to the female groups in May-June, when high-quality food was at its maximal availability, making female groups largest in this period. Similar to other sexually dimorphic species, Siberian ibex females and males stayed together in mixed-sex groups during rutting season, demonstrating sexual segregation outside of the rutting season, particularly during summer. Nevertheless, there are still a significant number of males and females that stay in mixed-sex groups throughout the year. In conclusion, the grouping pattern and social organization of Siberian ibex were closely correlated to the availability and quality of their food supply and yearly breeding cycle. Accordingly, Siberian ibexes changed their feeding strategy: being mixed feeders they behaved similar to concentrate selectors when food was scant and preferred small sized groups; while they enlarged their group sizes during seasons when the enriching of forage conditions allowed them to do that. However, group enlarging happened in different months depending on group typology (i.e. mixed-sex, male or female groups) depending on the feeding strategy of their individuals.
Earthworms are an important food resource for a large number of mammals and one of the most largely used method to assess their contribution to mammals' diet is the search for chaetae in faecal samples. Nevertheless, the observation and the identification of these bristles often require properly trained operators and suitable instruments, since their detection can be difficult and time-consuming. We tested the “standard” method for chaetae detection by washing 1046 scats – belonging to four mammal species of the Western Italian Alps (Vulpes vulpes, Martes spp., Lutra lutra, Sus scrofa) – through three sieves differing in mesh size (1.00, 0.54 and 0.21 mm). Mesh size significantly affected the detection of earthworm chaetae, suggesting that the use of three sieves should be recommended in faecal analyses. Moreover, both earthworm size and mean number of chaetae per individual should be assessed in each study area prior to diet analysis.
The phylogeographic analyses of the common hamster revealed the existence of five mitochondrial DNA (mtDNA) lineages. However, the analyses did not include Ukraine and the area outside Carpathian arch located in Romania that is important for the species as presumably refugial territory. We investigated both areas and described phylogeographic relationships of the populations on the basis of a partial cytochrome b (cytb, 904 bp) region of the mtDNA. Haplotype network and gene tree analyses did not produce a clear phylogeographic pattern for investigated territories that is typical for refugial populations. The highest diversity was found at the left bank of the River Dnieper and the area was called the Dnieper Lowland Refugial Area. Moreover only three from five described phylogeographic lineages (North, Pannonia and Caucasus) were fully separate on the network and gene trees. The haplotypes of other two lineages described previously from Eastern Europe (E1 and E0 lineages) mixed together with haplotypes from Ukraine and Moldovian Plateau. This study highlights the need for a re-examination of the phylogeography divisions of the common hamster.
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