Noninvasive genetic assessment of brown bear population structure in Bulgarian mountain regions

The Balkans are one of the last large refugia for brown bear (Ursus arctos) populations in Europe, and Bulgaria, in particular, contains relatively large areas of suitable brown bear habitat and a potential population of more than 600 individuals. Despite this, the majority of brown bear research remains focused on bear populations in Central and Western Europe. We provide the first assessment of genetic population structure of brown bears in Bulgaria by analysing tissue samples (n = 16) as well as samples collected with noninvasive genetic methods, including hair and faecal samples (n = 189 and n = 163, respectively). Sequence analysis of a 248 base pair fragment of the mitochondrial control region showed that two highly divergent mitochondrial European brown bear lineages form a contact zone in central Bulgaria. Furthermore, the analysis of 13 polymorphic microsatellite markers identified 136 individuals and found substantial genetic variability (H_e = 0.74; N_A = 8.9). The combination of both genetic markers revealed the presence of weak genetic substructure in the study area with considerable degrees of genetic admixture and the likely presence of migration corridors between the two subpopulation in the Rhodope Mountains and Stara Planina as evidenced from the genetic detection of two male long-distance dispersers. A detailed assessment from densely collected samples in the Rhodope Mountains resulted in a population size estimate of 315 (95% CI = 206–334) individuals, indicating that not all available habitat is presently occupied by bears in this region. Efficient management plans should focus on preserving connectivity of suitable habitats in order to maintain gene flow between the two Bulgarian brown bear subpopulations.     

On the association of giant short-faced bear (Arctodus simus) and brown bear (Ursus arctos) in late Pleistocene North America

Climate change and human impacts are often implicated in Quaternary megafaunal extinctions. The discovery of associated remains of extinct giant short-faced bears (Arctodus simus) and invading brown bears (Ursus arctos) raises the possibility of competition as another potential factor. We describe fossil remains of both genera from Pellucidar Cave, Vancouver Island, Canada. Analyses of ancient mitochondrial DNA support the identifications of post-cranial brown bear specimens and assign these bears to Clade 4. Our results are consistent with the migration of brown bears from Eastern Beringia to the contiguous United States before the Last Glacial Maximum (LGM) and to Vancouver Island as environmental conditions became favorable after the LGM. Radiocarbon age estimates on these specimens indicate the presence of giant short-faced bears approximately 13.5 thousand calibrated years before present (cal. ka BP; uncalibrated 11,775 ± 30, 11,720 ± 50, and 11,615 ± 30 BP) and of brown bears immediately preceding (～14.5 cal. ka BP; 12,440 ± 35, 12,425 ± 30 BP) and following this time (～13 cal. ka BP; uncal. 11,100 ± 30 BP), suggesting niche partitioning to reduce competition among these species. We suggest that shifts in food availability or quality due to post-glacial vegetation and faunal changes were probably of primary importance in the arrival and the disappearance of giant short-faced bears on Vancouver Island. This study focuses on a key time period and geographic location that is useful in understanding Pleistocene extinctions in North America.     

Cranial distinctiveness in the Apennine brown bear: genetic drift effect or ecophenotypic adaptation?

Molecular studies highlighted a strong genetic affinity between the remnant and isolated population of the Apennine brown bear and other southern European populations. Despite this genetic closeness a recent morphometric study revealed a marked phenotypic distinctiveness of the Apennine population, supporting the reinstatement of a distinct taxon (Ursus arctos marsicanus). By building upon previous morphological analyses, we adopted geometric morphometrics to better investigate the skull morphology of the Apennine brown bear with reference to the other, closely related southern European populations. Both skull shape and size differences confirmed the strong divergence of U. arctos marsicanus. In particular, the Apennine bears are characterized by an enlargement of the supraorbital apophysis and a larger distance across the zygomatic arches. Furthermore, our analyses highlighted significant shape differences of the first upper molar in the Apennine bears. Our results suggest that the Apennine bears underwent a rapid morphological change, possibly driven by genetic drift and local selective pressures. Because the greatest morphological differentiation is likely to be related to the muscles involved in mastication, we hypothesize that local selective pressures might be related to a shift in food habits, with highly reduced depredation and feeding on large carcasses in favour of vegetation and hard mast (beech nuts and acorns). These results suggest an adaptive distinctiveness of the Apennine bears, which should be carefully considered in any management and conservation action addressed to this highly endangered population. Although more in‐depth molecular studies are required to better assess the taxonomic and genetic status of the Apennine brown bear population, our study emphasizes the importance of morphological analyses as a complementary tool for a more thorough characterization of variation and divergence in endangered taxa. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ?? , ??–??.     

The dietary habits of the Brown bear (Ursus arctos) in western Greece

Knowledge of the dietary habits of an endangered species is essential to its management and conservation. The brown bear (Ursus arctos) exists in two isolated population in Greece, but only initial management actions have been taken to improve the habitat of this species. To improve our understanding of the ecology and habitat requirements of this species, we examined the dietary habits of the brown bear in the Panagia-Grevena region, of Macedonia, Greece. In total, 360 scats of brown bear were collected between 2002 and 2004 during spring, summer and autumn months. Scats were analyzed by their frequency of occurrence, volumetric and dry weights, and their importance values. Microhistological analysis was applied to estimate the proportion of wild and cultivated plants in the diet. The most important type of food in the spring was green vegetation, while, in the summer, fruits of Pyrus sp., Morus sp., Prunus sp. and Rubus sp. were important food items. In autumn, hard masts, mainly oak (Quercus sp.), were essential foods for the brown bear. The frequency of vertebrates in the diet was higher in the summer and autumn while that of invertebrates was higher in the spring. In summary, the brown bear is an omnivorous species that lives in Greece and adapts its diet according to food availability and human activities in its habitat. For this reason, human activities in the study area must take the needs and requirement of brown bears into consideration.     

Biomechanical consequences of rapid evolution in the polar bear lineage

The polar bear is the only living ursid with a fully carnivorous diet. Despite a number of well-documented craniodental adaptations for a diet of seal flesh and blubber, molecular and paleontological data indicate that this morphologically distinct species evolved less than a million years ago from the omnivorous brown bear. To better understand the evolution of this dietary specialization, we used phylogenetic tests to estimate the rate of morphological specialization in polar bears. We then used finite element analysis (FEA) to compare the limits of feeding performance in the polar bear skull to that of the phylogenetically and geographically close brown bear. Results indicate that extremely rapid evolution of semi-aquatic adaptations and dietary specialization in the polar bear lineage produced a cranial morphology that is weaker than that of brown bears and less suited to processing tough omnivorous or herbivorous diets. Our results suggest that continuation of current climate trends could affect polar bears by not only eliminating their primary food source, but also through competition with northward advancing, generalized brown populations for resources that they are ill-equipped to utilize.     

Both genetic and dietary factors underlie individual differences in DNA damage levels and DNA repair capacity

The interplay between dietary habits and individual genetic make-up is assumed to influence risk of cancer, via modulation of DNA integrity. Our aim was to characterize internal and external factors that underlie inter-individual variability in DNA damage and repair and to identify dietary habits beneficial for maintaining DNA integrity.Habitual diet was estimated in 340 healthy individuals using a food frequency questionnaire and biomarkers of antioxidant status were quantified in fasting blood samples. Markers of DNA integrity were represented by DNA strand breaks, oxidized purines, oxidized pyrimidines and a sum of all three as total DNA damage. DNA repair was characterized by genetic variants and functional activities of base and nucleotide excision repair pathways.Sex, fruit-based food consumption and XPG genotype were factors significantly associated with the level of DNA damage. DNA damage was higher in women (p = 0.035). Fruit consumption was negatively associated with the number of all measured DNA lesions, and this effect was mediated mostly by β-cryptoxanthin and β-tocopherol (p < 0.05). XPG 1104His homozygotes appeared more vulnerable to DNA damage accumulation (p = 0.001). Sex and individual antioxidants were also associated with DNA repair capacity; both the base and nucleotide excision repairs were lower in women and the latter increased with higher plasma levels of ascorbic acid and α-carotene (p < 0.05).We have determined genetic and dietary factors that modulate DNA integrity. We propose that the positive health effect of fruit intake is partially mediated via DNA damage suppression and a simultaneous increase in DNA repair capacity.     

Where the bears roam in Majella National Park,Italy

The Brown bear (Ursus arctos Linnaeus, 1758) occupies contiguous areas in Eastern and Northern Europe. In Western Europe, the largest remnant populations occur in Cantabria, Spain and the Apennines, Italy. Under Italian law the bear and its occupied range are protected. The occupied range of the Apennine brown bear includes Majella National Park. However, information on the distribution within Majella NP is extrapolated and inconsistent, thus precluding evidence-based protected area and species management. To address this lack of information, bear presence records (1996–2010) were collated and corrected for observational bias. Multiple Species Distribution Models (SDMs) were created at 800 m resolution to predict year-round and seasonal bear distribution. A hierarchical, stepwise maxent SDM approach was applied using climatic, terrain, vegetation, and anthropogenic predictors of bear distribution. Occupied ranges were identified by point density analysis of bear presence. Our climate-only SDMs predicted bear presence in areas with relatively low snowfall and temperate temperatures. Year-round bear distribution was also accurately predicted by using temperate-montane elevations and mesic, mesotrophic vegetation substrates, irrespective of vegetation. Ski-resorts were negative predictors of year-round bear occurrence. Bears were predicted in autumn and winter by beech forest, in spring by meadows and in summer by a variety of vegetation categories. The regional and our local models predicted bear throughout the south. However, our predicted and occupied range in the north includes the Orta valley and exclude alpine heights, contrary to the regional models. Only our summer bear range is similar to a regional SDM. We demonstrated that multiple maxent SDMs using a modest number of observations and a comprehensive set of environmental variables may generate essential distributional information for protected area and species management where full wildlife and food source censuses are lacking.     

Limited survey on aflatoxin contamination in rice

Aflatoxins (AFS) are toxic and carcinogenic fungal metabolites. Aflatoxin B1 is the most toxic and has been classified as a Group I carcinogen by the International Agency for Research on Cancer (IARC). Samples of imported rice were analyzed for their AFS content. Finley ground rice subsamples were extracted with water/methanol (100:150 v/v) followed by purification with Immunoaffinity columns (IAC). AFS purified from extracts were determined with RP-HPLC-FLD using post column electrochemical derivatization with a Kobra Cell. Concentrations of aflatoxin B1 and total AFS in test rice samples were ≤0.123 and ≤2.58 µg/kg, respectively. Tween 80 improved recoveries (86 and 106%) of aflatoxin B1 and aflatoxin G1 from brown rice. Recoveries of Aflatoxin B2 and aflatoxin G2 were substantially reduced (non-detected to 27%) by Tween 80 used in IAC cleanup of brown rice extracts. Visible dense growth of Aspergillus parasiticus (food isolate) occurred at 25 °C but higher aflatoxin B1amounts (23.9–39.3 µg/kg) accumulated when the mold grew at 37 °C in rice seeds stored for three weeks. It could be concluded that levels of aflatoxin B1 and total AFS in rice samples were within the permissible amounts of the EU and other international legislations.     

Spatial patterns in brown bear Ursus arctos diet: the role of geographical and environmental factors

• 1 We reviewed worldwide spatial patterns in the food habits of the brown bear Ursus arctos in relation to geographical (latitude, longitude, altitude) and environmental (temperature, snow cover depth and duration, precipitation, primary productivity) variables.
• 2 We collected data from 28 studies on brown bear diet based on faecal analysis, covering the entire geographical range of this widely distributed large carnivore. We analysed separately four data sets based on different methods of diet assessment.
• 3 Temperature and snow conditions were the most important factors determining the composition of brown bear diet. Populations in locations with deeper snow cover, lower temperatures and lower productivity consumed significantly more vertebrates, fewer invertebrates and less mast. Trophic diversity was positively correlated with temperature, precipitation and productivity but negatively correlated with the duration of snow cover and snow depth. Brown bear populations from temperate forest biomes had the most diverse diet. In general, environmental factors were more explicative of diet than geographical variables.
• 4 Dietary spatial patterns were best revealed by the relative biomass and energy content methods of diet analysis, whereas the frequency of occurrence and relative biomass methods were most appropriate for investigating variation in trophic diversity.
• 5 Spatial variation in brown bear diet is the result of environmental conditions, especially climatic factors, which affect the nutritional and energetic requirements of brown bears as well as the local availability of food. The trade‐off between food availability on the one hand, and nutritional and energetic requirements on the other hand, determines brown bear foraging decisions. In hibernating species such as the brown bear, winter severity seems to play a role in determining foraging strategies. Large‐scale reviews of food habits should be based on several measures of diet composition, with special attention to those methods reflecting the energetic value of food.

     

Brown bear reintroduction in the Southern Alps: To what extent are expectations being met?

Large carnivores, such as brown bears (Ursus arctos), are flagship species for the conservation of biodiversity and their reintroduction represents a strong challenge. However, the results of reintroductions have only recently been documented in the literature. Given the global decline of large carnivores, documenting the results of such attempts is crucial for future conservation management. Here we examined the reintroduction of brown bears into the Italian Alps. The majority of bears released (10 individuals) adapted well to the release area and this resulted in the increase of the brown bear population. At the end of 2012, the area with a stable presence of females was around 1250 km² (minimum density = 3 bear/100 km²). Between 2002 and 2012, 34 reproductive events occurred and a total of 74 cubs were born, thus reaching a minimum population size of 47 individuals. No less than 21 young males dispersed into adjacent Italian regions or into other countries, such as Switzerland, Austria, and Germany. However, despite a high mortality rate and at least two cases of illegal killing reported in the last 2 years (2013 and 2014), a remarkable population growth rate (current level of 15.6%) has been observed.The damages correlated with bear population size (F = 17.922, p < 0.01) were primarily inflicted on beehives (39%) and livestock (26%), with an economic relevance of € 41,374 per year for compensation and € 23,527 per year for prevention. The only case of injury to humans ever since the beginning of the project was recorded in 2014, when a female defending her two cubs inflicted minor physical injuries to a man. And yet, public opinion changed radically, from a widespread acceptance of bears at the beginning of the project to an opposition to their presence, the increase of their population, and the new translocations aiming at replacing problem bears that had previously been removed. According to the present trend, the population may reach a range of 60–94 individuals in 2017. Therefore, a proper management of problem bears should be considered a key factor for the restoration and improvement of the social acceptance of this species.     

青藏高原可可西里地区藏棕熊暖季食性及采食行为模式

藏棕熊(Ursus arctos pruinosus)是青藏高原特有的棕熊亚种,作者曾对该地区藏棕熊夏季食性进行了初步报道(Xu et al,2006),然而,藏棕熊的采食行为模式一直未见报道。2009年7-8月,作者又对可可西里地区藏棕熊食性及采食行为模式做了补充调查研究,对两次考察所获得的数据进行了整合分析,研究结果表明,该地区藏棕熊主要以动物性食物为主,其中,高原鼠兔(Ochotona curzoniae)的相对频次为37.3%和干物质量为44.7%,下同);野牦牛(Bos grunniens)分别为18.7%和30.2%;藏羚(Pantholops hodgsoni)分别为15.0%和16.2%。藏棕熊在可可西里地区有两种采食行为模式:主动捕食高原鼠兔和采食藏羚、藏原羚和野牦牛尸体。观察期间藏棕熊约用10%的时间挖掘高原鼠兔的洞穴捕捉高原鼠兔,但未见藏棕熊主动捕食大型哺乳动物。粪样分析结果发现,藏棕熊主动捕食的高原鼠兔和喜马拉雅旱獭(Marmota himalayana)和通过食腐方式获得的藏羚、藏原羚和野牦牛的生物量基本相等。     

The brown-world role of insectivores: Frogs reduce plant growth by suppressing detritivores in an alpine meadow

Predators of plant-suppressing herbivores have long been known to indirectly enhance plant biomass, while more recent work has revealed that predators of plant-facilitating detritivores can have the opposite effect on plant biomass. Generalist predators, such as frogs that typically facilitate plant growth in green food webs, may potentially negatively affect plant growth by consuming prey from brown food webs. In a marshy Tibetan alpine meadow, we tested the hypothesis that the locally abundant frog Rana kukunoris could negatively affect plant growth through suppression of dung-decomposing detritivores that promote plant growth by enhancing nutrient recycling. We conducted a factorial experiment (presence/absence of predators × presence/absence of dung) using replicate field enclosures over a growing season. Where dung was present, frogs significantly reduced the number of dung-feeding beetles and dung-feeding flies (including fly eggs and maggots) per dung pat, thereby decreasing dung mass loss and, indirectly, aboveground plant biomass (by 22%) surrounding dung pats. Where dung was absent, frogs did not affect plant biomass. Moreover, the number of dung beetles was positively associated with dung mass loss and soil soluble N concentration (but not total N concentrations), which in turn positively correlated with aboveground plant biomass. These results indicate that a generalist predator species standing in green food webs may play a contrasting role in brown food webs and indicate that a more nuanced appreciation of the functional role of predators in tri-trophic systems is required to accurately predict their cascading effects. Future studies must assess the relative strength of cascading effects mediated through brown and green channels in order to assess the net cascading effects of generalist predators in natural food webs.     

Spotted hyena (Crocuta crocuta) coexisting at high density with people in Wukro district,northern Ethiopia

We surveyed density and abundance of spotted hyena (Crocuta crocuta) in the highly degraded and prey depleted Wukro district, northern Ethiopia, with a human population density of 98 persons per square kilometer. A total of 117 spotted hyenas responded to callups, giving a hyena density of 52 hyenas per 100 km² or a total population of 535 hyenas in the district. We quantified the economic impact of spotted hyena predation on livestock using semi structured interviews with randomly selected households. Respondents indicated a total loss of 203 domestic animals to hyena depredation over the past five years. Average annual depredation per household was 0.13 livestock worth US$ 6.1. The diet of spotted hyenas was assessed in three sub-districts by scat analysis and showed 99% prey items of domestic origin, only three of 211 scat contained hair of Ethiopian hare (Lepus fagani) and porcupine (Hystrix cristata). We conclude that hyenas in northern Ethiopia live at high density and eat almost exclusively anthropogenic food and are not dependent on conservation areas.     

Alternative procedures for the cryopreservation of brown bear ejaculates depending on the flexibility of the “in cooling” period (5 °C)

The adaptability of cryopreservation protocols for brown bear spermatozoa collected under field conditions and frozen in a nearby laboratory (transported for a few hours) or shipped to a reference laboratory for sex sorting (transported for a few days) was evaluated. Forty-nine electroejaculates from 15 mature brown bears were extended to 100 × 10⁶ sperm/mL in a TES-Tris-Fructose based extender and cryopreserved (−20 °C/min to −100 °C and stored at −196 °C). After thawing, the quality of the seminal samples was assessed for total (TM), progressive (PM) motility and kinetic parameters – by CASA –, and viability (VIAB), viable and non-apoptotic status (YOPRO−), high membrane mitochondrial potential (MIT) and intact acrosomes (iACR) – by flow cytometry –. In Experiment 1, we assessed different storage times (0, 0.5, 1 – control –, 4–5, 7–8 and 11–12 h) at 5 °C from final dilution to freezing. After thawing, non-equilibrated samples (0 h) showed lower values of iACR, TM and PM. No significant differences were found for the different periods of equilibration tested. In Experiment 2, we evaluated three long-term storage times (24, 48 and 72 h) at 5 °C before freezing using storage for 1 h as control. The post-thawing quality of brown bear spermatozoa declined markedly after 48–72 h of pre-freezing. In conclusion, our findings suggest the possibility of extending the pre-freezing cooling period up to 24 h post-collection without freezing. This knowledge should enable the adaptation of the freezing protocols for when a special handling conditions are required such as the shipment of seminal samples to technological centers for the pre-freezing application of enhancer spermatic biotechnologies.     

Associations between oral hygiene habits,diet, tobacco and alcohol and risk of oral cancer: A case–control study from India

ObjectiveThis study examines the association between the incidence of oral cancer in India and oral hygiene habits, diet, chewing and smoking tobacco, and drinking alcohol. We also assessed the effects of oral hygiene habits with oral cancer risk among chewers versus never chewers.MethodsA hospital-based case–control study was conducted in Pune, India, based on face-to-face interviews, anthropometry, and intra-oral examinations conducted for 187 oral cancer cases and 240 controls.ResultsPoor oral hygiene score was associated with a significant risk of oral cancer (adjusted OR = 6.98; 95%CI 3.72–13.05). When stratified by tobacco-chewing habit, the poor oral hygiene score was a significant risk factor only among ever tobacco chewers (adjusted OR = 14.74; 95%CI 6.49–33.46) compared with never chewers (adjusted OR = 0.71; 95%CI 0.14–3.63). Dental check-ups only at the time of pain by ever-chewers with poor oral hygiene was associated with an elevated risk (adjusted OR = 4.22; 95%CI 2.44–7.29), while consumption of green, yellow, and cruciferous vegetables and citrus fruits was protective. A linear dose–response association was observed between oral cancer and chewing tobacco in terms of age at initiation, duration, and frequency of chewing per day (P < 0.001). Smoking more than 10 bidis/cigarettes per day (adjusted OR = 2.74; 95%CI 1.28–5.89) and for a duration >25 years (adjusted OR = 2.31; 95%CI 1.14–4.71) elevated the risk of oral cancer.ConclusionGood oral hygiene habits – as characterized by healthy gums, brushing more than once daily, use of toothpaste, annual dental check-ups, and a minimal number of missing teeth – can reduce the risk of oral cancer significantly. In addition to refraining from chewing/smoking tobacco, a diet adequate in fruits and vegetables may protect against the disease.     

International variability in diet and requirements of manganese: Causes and consequences

Manganese (Mn) is an essential trace element that is critical for human health and development. At the turn of the century when diets were based on whole grains, cereals and other traditional foods, Mn intakes (8–9 mg/d) were much greater than that prevalent today (2 mg/d). As societies have developed, diets have shifted as part of a nutrition transition, to those that are high in processed foods, fat, and sugar. These foods are virtually devoid of Mn. Thus, dietary Mn has declined substantially throughout the world, as confirmed by several wide-scale, total diet studies.International variability in dietary Mn is considerable, due to tremendous diversity in food and culture. In countries where fruit and vegetable intake may be limited, i.e. the United Kingdom, populations may ingest much lower levels of Mn (1.4 mg/d) as compared to Asian cultures (4 mg/d) which have an abundance of plant foods in their food supply and cuisine. The bioavailability of Mn must be considered, including chemical form, oxidation state, mineral-mineral interactions, presence of dietary components and traditional food processing techniques (milling, germination, malting, fermentation). Manganese toxicity is a public health problem that results from exposure to a naturally high water source or contaminated environment of the soil and/or drinking water. In contrast, inadequate intake is associated with adverse health effects such as diabetes, metabolic syndrome, poor birth outcomes and possibly, cancer. Future studies are recommended to set dietary standards for this mineral in countries that lack recommendations to help achieve optimal health.     

Calidad de la alimentación de adultos mayores de Santiago de Chile

IntroductionWith the increase in the elderly population of Chile, it is very important to evaluate the quality of food of this age group using simple and quick tools.ObjectiveTo compare the food quality of the elderly, according to gender and age.Material and methodsA cross sectional study was conducted on 458 elderly subjects ≥ 60 years-old of Santiago de Chile. Each one of them were interviewed in their home using the Food Quality Survey for Elderly (FQSE). The objective of this survey is to measure the quality of the food and preparations considered healthy and/or unhealthy for elderly. Weight and height, was obtained from the control document of the elderly.ResultsMen consume a higher number of unhealthy foods compared to women (P = .01). On comparing ages, those over 80 years-old consumed less unhealthy foods (P = .01). The elderly obese showed a lower score in unhealthy eating habits and total intake score.ConclusionWomen eat healthier compared to men, and better eating habits are observed at an older age, especially in men. Finally, on comparing nutritional status, the elderly obese are those who eat in the most inadequate form.     

The natural diet of the mud crab Scylla olivacea (Herbst, 1896) in Pichavaram mangroves,India

Food and feeding habits of mud crab Scylla olivacea (Herbst, 1896) in Pichavaram mangroves was investigated quantitatively and qualitatively for a period of two years from June 2010 to May 2012. Gut contents from 1737 specimens comprising 843 males and 894 females in the size range between 45 mm and 148 mm were examined. Crustaceans form the predominant food item in a majority of size groups in terms of percentage wet weight and frequency of occurrence, while molluscs showed a preference in few size groups. The other dietary items includes fishes, detritus, mud and sand and miscellaneous. Gut content analysis revealed no significant variation between the quantities of food consumed by both sexes. Feeding intensity was higher in juveniles and subadults of both sexes than that of adults, revealing a greater preference to feed on fast moving prey such as crustaceans and fishes. The results of the present study indicate that S. olivacea in Pichavaram mangroves exhibited a clear preference for crustaceans.     

Responses of wolf feeding habits after adverse climatic events in central-western Belarus

Many studies have investigated the ecology of wolf populations of Eurasia, showing that although wolves are mostly opportunistic in seeking meso-large enough mammalian prey, they can also be selective, depending on local availability of prey and their population biomass. Yet prey preferences of the wolf have been poorly evaluated in situations of complex predator/prey systems because such ecological situations are extremely rare in Europe. In particular, the role of beaver is poorly known due to the extreme decline in its range and population over the last few centuries.We conducted a 15-year study (1999–2014) of wolf Canis lupus diet in the Naliboki forest of central-western Belarus to determine the dietary responses of the wolf population in a context of a rich prey supply (beaver 650 inds/100 km², elk 47 inds/100 km², red deer 98 inds/100 km, roe deer 398 inds/100 km², wild boar 234 inds/100 km²). The bison, although present, is not preyed on. We compared the seasonal and annual diet variations of both wolf adults and pups, by scat analysis and hair identification. In winter 2012–2013, the winter was quite harsh with a long period of snow, which severely affected the roe deer and wild boar populations. Five severe summer droughts also occurred (1999, 2001, 2002, 2004 and 2013), greatly decreasing the water level in rivers and canals. We took advantage of these stressful events to evaluate the diet responses of the wolves.In “normal” years, we identified 11 food categories, essentially beaver and medium-sized ungulates (66%), and large ungulates to a lesser extent (9% in summer, 20% in winter). The adults were found to selectively supply pups with beaver, probably because of its easy transportability. Beaver consumption also increased during summer droughts when water levels were very low. After the harsh winter of 2012–2013, which was followed by a sharp decline in medium-sized prey, we observed a shift in the winter diet breadth of the wolves towards greater consumption of both large wild ungulates and small carnivores. We concluded that:1. Beaver is a functional element in wolf ecology, as a primary food for adults and pups;2. A large range of available prey species is important to maintaining a viable wolf population in cases of extreme climatic events.     

Feeding enrichment in an opportunistic carnivore: The red fox

In captive carnivores, species-specific behaviour is often restricted by inadequate feeding regimens. Feeding live prey is not feasible in most places and food delivery is often highly predictable in space and time which is considerably different from the situation in the wild. As a result, captive carnivores are often inactive, show little behavioural diversity and are prone to behavioural problems such as stereotypic pacing. Using artificial feeding devices to substitute for natural food resources is a way to address these problems. In a group of four red fox (Vulpes vulpes), we compared a conventional feeding method to four different methods through the use of feeding enrichment that were based on natural foraging strategies of opportunistic carnivores. Feeding enrichments consisted of electronic feeders delivering food unpredictable in time which were successively combined with one of the three additional treatments: a self-service food box (allowing control over access to food), manually scattering food (unpredictable in space), and an electronic dispenser delivering food unpredictably both in space and time. The aim of administering feeding enrichment in this study was to stimulate appetitive (food searching) behaviour and to increase time spent in feeding. Compared to conventional feeding, diversity of behaviour and overall activity were significantly enhanced in the presence of electronic feeders in all four foxes (EF > CON1 = CON2, EF + SF > CON1 = CON2, EF + MS > CON1 = CON2, EF + ED > CON1 = CON2). Behavioural diversity was highest when the foxes had control over access to food (EF + SF), while the manual scattering of food (EF + MS) and the electronic dispenser (EF + ED) enhanced food searching behaviour. These results indicate that in opportunistic carnivores natural foraging and feeding behaviour can be stimulated by simple feeding enrichment strategies, and that foraging behaviour is stimulated most when food delivery is unpredictable both in space and time.