Space use patterns of mountain hare (<Emphasis Type="Italic">Lepus timidus</Emphasis>) on the Alps

Populations on the limits of species’ distribution can show different behavioral adaptations to strong ecological pressure than in the central part of the range. We investigated space use patterns of alpine mountain hare (Lepus timidus) at two areas on the southern edge of the species’ range. We monitored 34 hares between 2005 and 2008, estimating home range size, overlap, and site fidelity, and compared our results with space use in Scottish and North-European populations. Home ranges of mountain hares did not differ between two study areas with different habitat types. Subadult animals used larger ranges than adults and both age groups reduced home range size in autumn, a period that might be critical for hares due to changes in diet and/or high energy expenditure during the previous breeding season. Home ranges in these alpine populations were smaller than in Scandinavian populations but within the range of populations in different habitat types in Scotland. Seasonal home ranges overlapped considerably, but differed among the sexes: male–female overlap was higher than same sex (male–male and female–female) spatial overlap. Seasonal shifts of home ranges were small, and site fidelity remained high over the seasons, suggesting that resource distribution remained constant throughout the year and that the knowledge of an intensively frequented area is an important element of habitat quality. We concluded that habitat structure and availability of mates interact in affecting mountain hare space use in alpine habitats.     

The effects of seed availability on habitat use by a specialist seed predator

Space-use patterns of seed predators are strongly affected by spatiotemporal variation in the abundance of different tree seeds, their major food source. However, most studies have measured relationships between overall food availability and space use, and there are few cases where effects of different food resources have been explored. We studied the effects of two food resources, Norway spruce and silver fir seeds, on space and habitat use in red squirrel in a subalpine conifer forest from 2000 to 2006. Fir seeds disperse in the autumn of the year they are produced, spruce the following spring. We estimated spruce and fir seed availability within individual home ranges and monitored home-range size using radiotelemetry. Males had larger home ranges than females and the sexes responded differently to variation in food and density. Spruce seed availability negatively affected home-range and core-area sizes of males in spring–summer. Space use was not affected by fir seed availability. Squirrels positively selected spruce for foraging and spruce was always preferred over fir. Our results showed that spruce, but not fir, affected space and habitat use of squirrels, suggesting they do not behaviourally respond to early seed dispersal in fir.     

Spacing behaviour and habitat use of rock ptarmigan (Lagopus mutus) at low density in the Italian Alps

Studies of rock ptarmigan Lagopus mutus in northern latitudes have shown that, in the breeding season, the majority of cocks pair monogamously and defend small territories, whilst in most populations, a small proportion of cocks are polygynous or remain unmated. Little is known, however, on spacing behaviour and habitat use of alpine rock ptarmigan populations occurring at low densities at the southern edge of the species’ range. From 1995 to 1997, we trapped, radio-tracked and observed birds in the Central Italian Alps (elevation 2,000–3,000 m) in order to investigate spacing behaviour and habitat use in alpine landscapes where habitats offering rich food and cover are patchy. Both sexes were selective in their habitat use, and cocks did not establish territories on bare ground, artificial or nutrient rich grasslands or bogs. In the breeding season, cocks had larger home ranges than hens (cocks 99 ± 57 ha, hens 50 ± 25 ha) that overlapped with the ranges of neighbouring cocks and hens. Cocks were monogamous and defended relatively large territories (core areas of home ranges: cocks 37 ± 26 ha, hens 24 ± 12 ha), which corresponded with low spring densities (0.47–2.29 cocks km⁻² and 0.35–1.60 pairs km⁻²). Territory size of individual cocks was negatively correlated with the amount of high quality habitat in the core-area. Our results suggest increased home ranges and large breeding territories in low density alpine rock ptarmigan populations, compared to populations occurring at higher densities in the central and northern alps, and on subarctic and arctic grounds at northern latitudes, confirming the predictions of models on food-based territoriality.     

Effects of spatial variation in food availability on spacing behaviour and demography of Eurasian red squirrels

In heterogeneous habitats with limited resources, spacing behaviour will affect individual variation in breeding success and density of populations, and is thus of general interest to ecologists. We investigated how red squirrels Sciurus vulgaris adapt their social organisation to tine‐grained heterogeneity in habitat quality, studying spacing behaviour, habitat use and population dynamics in a forest in north Italy, characterised by a mosaic of high‐quality (chestnut‐pine) and poor‐quality patches. We compared the data with those from more homogeneous broadleaf and mixed woodlands with similar overall tree seed abundance (“stable” habitats). Squirrels lived at lower densities (pre‐breeding density 0.39‐0.58 ha^‐1) than in “stable” habitats, although breeding rate was not reduced. Female breeding success was related to being primiparous as yearlings, and increased with body mass and proportion high‐quality habitat in the home range. Persistency rate of females was as in stable habitats, It was higher than male persistency, but immigration and recruitment rates were male biased, resulting in even sex‐ratio. All residents occupied high‐quality patches, and no subadults established a permanent home range in poor‐quality habitat. Home range and core‐area size was typically larger in males than in females and a male's core‐area overlapped those of other males and of females. Female core‐areas were overlapped by males but not. or very little, by other females (intrasexual territoriality). Home ranges, or core‐areas, were not smaller than in “stable” habitats, nor did we find a higher degree of core‐area overlap. We conclude that in patchy habitats dominant, resident red squirrels exclude dispersing animals from preferred, high‐quality habitat, producing a spacing pattern referred to as ideal despotic distribution, and that poor patches were only used temporarily by transient individuals, resulting in a reduction of density in comparison to populations in “stable” habitats.     

Invading parasites: spillover of an alien nematode reduces survival in a native species

Biological Invasions - It is widely assumed that spillover of alien parasites to native host species severely impacts naïve populations, ultimately conferring a competitive advantage to...     

New enrichment method for isolation of pathogenic Yersinia enterocolitica serogroup O:3 from pork

A new enrichment medium for the recovery of pathogenic Yersinia enterocolitica serogroup O:3 from naturally infected meat products based on three selective agents, Irgasan, ticarcillin, and potassium chlorate (ITC), was compared with several other one- or two-step enrichments. Y. enterocolitica serogroup O:3 was recovered from 96.5% of 29 pork tongues, 24% of 50 ground pork samples, 16% of 25 masseter muscle samples, and 61% of tonsils. ITC was by far the most sensitive method for the recovery of Y. enterocolitica O:3, especially from ground meat and masseter muscles, while cold and two-step enrichments yielded better results for nonpathogenic strains. Plating of ITC enrichments onto SS-deoxycholate-calcium agar gave overall better results than plating onto cefsulodin-Irgasan-novobiocin agar for serogroup O:3.     

Nickel tolerance and accumulation by bacteria from rhizosphere of nickel hyperaccumulators in serpentine soil ecosystem of Andaman, India

Rhizosphere microorganisms harboring nickel hyperaccumulators, Rinorea bengalensis (Wall.) O. K. and Dichapetalum gelonioides ssp. andamanicum (King) Leenh. endemic to serpentine outcrops of Andaman Islands, India, were screened for their tolerance and accumulation of Ni. The rhizosphere soils from both the plants were rich in total and available Ni along with Co, Cr, Fe and Mg but poor in microbial density and were dominated by bacteria. Out of total 123 rhizosphere microorganisms (99 bacteria and 24 fungi), bacteria were more tolerant to Ni than fungi. Viable cells of selected Ni-tolerant bacterial isolates (MIC = 13.6–28.9 mM Ni) belonging to Pseudomonas, Bacillus and Cupriavidus were capable of accumulating nickel (209.5–224.0 μM Ni g⁻¹ protein) from aqueous solution. Cupriavidus pauculus KPS 201 (MTCC 6280), showing highest degree of nickel tolerance (MIC 28.9 mM Ni) and uptake (224.0 μM Ni g⁻¹ protein, 60 min) was used for detailed study. Kinetics of nickel uptake in C. pauculus KPS 201 followed a linearized Lineweaver-Burk plot. The K _m and V _max for nickel uptake by minimal medium grown-cells approximated 1.5 mM Ni and 636.9 μM Ni g⁻¹ protein, respectively. The uptake process was inhibited by Co, Cu, Cd, Mg, Mn and Zn, however, complete inhibition was not achieved even in presence of 500 mM Mg. Metabolic inhibitors, sodium azide (1.0 mM) and carbonyl cyanide m-chlorophenylhydrazone (0.4 mM) strongly inhibited nickel uptake suggesting the process as an energy dependent one. The present study clearly shows that bacteria in the rhizosphere of Ni-hyperaccumulators are capable of tolerating high concentration of Ni and also possesses nickel uptake potential. The Ni-hyperaccumulators in combination with these Ni-resistant bacteria could be an ideal tool for nickel bioremediation.