Rural populations of the red fox Vulpes vulpes show little evidence of reproductive senescence

The ageing theory predicts fast and early senescence for fast-living species. We investigated whether the pattern of senescence of a medium-sized, fast-living and heavily-culled mammal, the red fox (Vulpes vulpes), fits this theoretical prediction. We used cross-sectional data from a large-scale culling experiment of red fox conducted over six years in five study sites located in two regions of France to explore the age-related variation in reproductive output. We used both placental scars and embryos counts from 755 vixens’ carcasses aged by the tooth cementum method (age range: 1–10), as proxies for litter size. Mean litter size per vixen was 4.7 ± 1.4. Results from Generalized Additive Mixed Models revealed a significant variation of litter size with age. Litter size peaked at age 4 with 5.0 ± 0.2 placental scars and decreased thereafter by 0.5 cubs per year. Interestingly, we found a different age-specific variation when counting embryos which reached a plateau at age 5–6 (5.5 ± 0.2) and decreased slower than placental scars across older ages, pointing out embryo resorption as a potential physiological mechanism of reproductive senescence in the red fox. Contrary to our expectation, reproductive senescence is weak, occurs late in life and takes place at an age reached by less than 11.7% of the population such that very few females exhibit senescence in these heavily culled populations.     

Initiation of the breeding season in ewe lambs and goat kids with melatonin implants

Sixty-eight female and 4 male lambs of the Chios breed born in autumn (September–October) and 48 female and 4 male kids of the Damascus breed also born in autumn (November), were used to evaluate the effect of melatonin implants (Regulin^®) on the initiation of the breeding season. For each species and sex, half of the animals were either left untreated to serve as controls (C) or received ear implants (females one and males two implants) of melatonin (MEL) in May (spring). Each C and MEL group of females was kept separately and away from males for 5 weeks after implantation and then, C and MEL males were joined with the respective groups for 45 (sheep) and 35 days (goats). Animals not conceiving during the early June–July breeding season, were mated again in September (natural breeding season). The reproductive performance and the 60-day milk yield of animals giving birth during the two seasons were compared. Early in the season (mid November–December), significantly more MEL than C ewes and goats gave birth (75.5% versus 23.5%, p < 0.01; 70.8% versus 37.5%, p < 0.05, respectively). For both species, most of the other characteristics examined were significantly affected by season, but not by treatment. Females giving birth early in the season were approximately 80 days younger at parturition and recorded a lower body weight at mating than those giving birth in the natural February–March season. In the first mating period, the animals mated and conceived had similar body weights to those not mated. The natural, compared with the early June–July mating season, was associated in sheep with higher litter weight at birth (7.0 kg versus 5.8 kg, p < 0.05) and in sheep and goats with a higher number (p < 0.05) of offspring born live (1.78 versus 1.38; 2.0 versus 1.61, respectively) and weaned (1.74 versus 1.36; 1.82 versus 1.35, respectively). Total litter size at birth and 60-day milk yield after weaning, were not significantly different between the two seasons. It could be concluded that melatonin implants administered during the last month of spring in autumn-born female Chios sheep and Damascus goats, advanced the initiation of their breeding season by about 80 days when joined with young males also treated with melatonin implants. The overall reproductive performance and milk yield of animals breeding early, was satisfactory and comparable to that of animals breeding in the natural breeding season.     

Puma spatial ecology in open habitats with aggregate prey

Solitary felids are commonly associated with structurally complex habitats, where their foraging success is attributed to stealth and remaining undetected by competitive scavengers. Research in North America suggests that pumas (Puma concolor), a wide-ranging species found throughout the Americas, conform to the general characteristics of solitary felids and avoid open grasslands with aggregating prey. Researchers hypothesize that pumas are limited to structurally complex habitats in North America because of pressures from other large, terrestrial competitors. We explored the spatial ecology of pumas in open habitat with aggregating prey in Chilean Patagonia, where pumas lack large, terrestrial competitors. We tracked 11 pumas over 30 months (intensive location data for 9 pumas with GPS collars for 9.33 ± 5.66 months each) in an area where mixed steppe grasslands composed 53% of the study area and carried 98% of available prey biomass, to track resource use relative to availability, assess daily movements, quantify home ranges and calculate their density. As determined by location data and kill sites, Patagonia pumas were primarily associated with open habitats with high prey biomass, but at finer scales, preferentially selected for habitat with complex structure. On average, pumas traveled 13.42 ± 2.50 km per day. Estimated 95% fixed kernel home ranges averaged 98 ± 31.8 km² for females and 211 ± 138.8 km² for males, with high spatial overlap within and between the sexes. In a multivariate analysis, available prey biomass was the strongest predictor of variation in the size of an individual puma's home range. Finally, we determined a total puma density of 3.44 pumas/100 km², a significantly smaller estimate than previously reported for Patagonia, but similar to densities reported for North America.     

Birth Timing for Mountain Lions (Puma concolor); Testing the Prey Availability Hypothesis

We investigated potential advantages in birth timing for mountain lion (Puma concolor) cubs. We examined cub body mass, survival, and age of natal dispersal in relation to specific timing of birth. We also investigated the role of maternal age relative to timing of births. We captured mountain lion cubs while in the natal den to determine birth date, which allowed for precise estimates of the population birth pulse and age of natal dispersal. A birth pulse occurred during June–August. Body mass of cubs was related to litter size and timing of birth; heaviest cubs occurred in litters of 2, and those born after 1 July. Cubs born within pulse months exhibited similar survival to those born out of the pulse. We found that cubs born April–June dispersed at younger ages than those born after 1 July. There was less variation in birth timing for 1^st litters of females than older females. We hypothesize that cubs born after the peak in births of neonate prey are advantaged by the abundance of vulnerable prey and those cubs and mothers realize an evolutionary advantage.     

Synchronization of estrus with short- and long-term progestagen treatments and the use of GnRH prior to short-term progestagen treatment in ewes

The objective of the present study was to determine the efficacy of the synchronization of estrus using short- and long-term progestagen treatments in ewes at the onset of the breeding season, and to evaluate the effect of the exogenous GnRH administration immediately prior to short-term progestagen treatment on the reproductive performance. A total of 240 Tahirova cross-bred ewes, aged 18–24 months, and 40 rams, aged 2–4 years-old, were used in the trial. Ewes were divided equally into 3 groups (n = 80 per group). Intravaginal progestagen sponges containing FGA (30 mg) were inserted in the ewes for 7 d in the FGA1 (short-term) and GnRH treatment groups, and for 12 d in the FGA2 group (long-term). The ewes in the GnRH group received 10.5 μg busereline acetate i.m. at the time of sponge insertion. Tiaprost tromethamol (PGF_2α; 0.294 mg) and eCG (400 IU) were injected i.m. on the 6th day of progestagen treatment in the GnRH and FGA1 groups, and on the 11th day in the FGA2 group following sponge insertion. All ewes were hand-mated once at the detection of estrus. The estrous response, fertility rate, multiple birth rate and litter size recorded was 88.7, 87.3, 51.6% and 1.6 in the FGA1 group, 92.5, 71.6, 50.9% and 1.5 in the FGA2 group, and 96.2, 89.6, 71.0% and 1.8 in the GnRH group, respectively. No significant difference in estrous response between the groups was recorded, but the fertility rate in the FGA1 and GnRH groups was significantly (P < 0.05) higher than in the FGA2 group. The occurrence of multiple births and litter sizes were significantly (P < 0.05) higher in the GnRH group, compared to both the FGA1 and FGA2 groups, with the number of single lambs being significantly (P < 0.05) higher in the FGA1 (48.4%) and FGA2 (49.0%) groups than in the GnRH (29.0%) group. However, the differences recorded between any of the groups in terms of the number of twin and triplet lambs were insignificant. In conclusion, it can be said that estrous synchronization using the 12-d-FGA-eCG-PGF_2α regimen could be replaced with the 7-d-FGA-eCG-PGF_2α regime in sheep at the onset of the breeding season. However, the combination of GnRH with the latter regimen (7-d-GnRH-FGA-eCG-PGF_2α) increased the multiple birth rate and litter size in the ewes.     

Can cryptophyte abundance trigger toxic Karlodinium veneficum blooms in eutrophic estuaries?

Karlodinium veneficum is a common member of the phytoplankton in coastal ecosystems, usually present at relatively low cell abundance (10² to 10³ mL⁻¹), but capable of forming blooms of 10⁴ to 10⁵ cells mL⁻¹ under appropriate conditions. We present evidence consistent with the hypothesis that prey abundance, particularly the abundance of nano-planktonic cryptophytes, is a key factor driving the formation of toxic K. veneficum blooms in eutrophic environments. K. veneficum is known to increase growth rate 2- to 3-fold in culture through mixotrophic nutrition, but the role of feeding in bloom formation has not been directly examined. We find that toxic K. veneficum blooms are correlated with cryptophytes abundance changes. We find a wide range of mixotrophic feeding capabilities (0–4 prey per predator per day) among genetically distinct strains of K. veneficum when fed a common prey. Finally, we find that toxic K. veneficum is capable of feeding on a wide range of cryptophyte species varying in size (31–421 μm³ per cell) and phylogenetic affinity, although ingestion rates of different prey vary significantly. While abiotic conditions (e.g. nutrients and advection) are an important aspect of K. veneficum bloom formation in eutrophic environments, our results reinforce the need for a broader view of conditions leading to toxic K. veneficum blooms including biotic factors such as prey availability.     

Oxidative stress programming in a rat model of postnatal early overnutrition — role of insulin resistance

Postnatal early overfeeding (EO) is related to later development of overweight and other metabolic disorders. As oxidative stress is implicated in most human diseases, as obesity and diabetes, we decided to study some parameters related to oxidative stress and insulin signaling in liver from EO animals in adult life. To induce EO, litter size was reduced to three pups per litter (SL: small litter) and groups with normal litter size (NL:10 pups per litter) were used as control. After weaning, rats had free access to standard diet and water. Body weight and food intake were monitored daily and offspring were killed at 180 days-old. Significant differences had P<.05 or less. As expected, SL rats had hyperphagia, higher body weight and higher visceral fat mass at weaning and adulthood. In liver, postnatal EO programmed for lower catalase (? 42%), superoxide dismutase (? 45%) and glutathione peroxidase (? 65%) activities. The evaluation of liver injury in adult SL group showed lower nitrite content (? 10%), higher liver and plasma malondialdehyde content (+ 25% and 1.1-fold increase, respectively). No changes of total protein bound carbonyl or Cu/Zn superoxide dismutase protein expression in liver were detected between the groups. Regarding insulin signaling pathway in liver, SL offspring showed lower IRβ (? 66%), IRS1 (? 50%), phospho-IRS1 (? 73%), PI3-K (? 30%) and Akt1 (? 58%). Indeed, morphological analysis showed that SL rats presented focal areas of inflammatory cell infiltrate and lipid drops in their cytoplasm characterizing a microsteatosis. Thus, we evidenced that postnatal EO can program the oxidative stress in liver, maybe contributing for impairment of the insulin signaling.     

A comparison of algal,macroinvertebrate, and fish assemblage indices for assessing low-level nutrient enrichment in wadeable Ozark streams

Biotic indices for algae, macroinvertebrates, and fish assemblages can be effective for monitoring stream enrichment, but little is known regarding the value of the three assemblages for detecting perturbance as a consequence of low-level nutrient enrichment. In the summer of 2006, we collected nutrient and biotic samples from 30 wadeable Ozark streams that spanned a nutrient-concentration gradient from reference to moderately enriched conditions. Seventy-three algal metrics, 62 macroinvertebrate metrics, and 60 fish metrics were evaluated for each of the three biotic indices. After a group of candidate metrics had been identified with multivariate analysis, correlation procedures and scatter plots were used to identify the four metrics having strongest relations to a nutrient index calculated from log transformed and normalized total nitrogen and total phosphorus concentrations. The four metrics selected for each of the three biotic indices were: algae—the relative abundance of most tolerant diatoms, the combined relative abundance of three species of Cymbella, mesosaprobic algae percent taxa richness, and the relative abundance of diatoms that are obligate nitrogen heterotrophs; macroinvertebrate—the relative abundance of intolerant organisms, Baetidae relative abundance, moderately tolerant taxa richness, and insect biomass; fish—herbivore and detritivore taxa richness, pool species relative abundance, fish catch per unit effort, and black bass (Micropterus spp.) relative abundance.All three biotic indices were negatively correlated to nutrient concentrations but the algal index had a higher correlation (rho = ?0.89) than did the macroinvertebrate and fish indices (rho = ?0.63 and ?0.58, respectively). Biotic index scores were lowest and nutrient concentrations were highest for streams with basins having the highest poultry and cattle production. Because of the availability of litter for fertilizer and associated increases in grass and hay production, cattle feeding capacity increases with poultry production. Studies are needed that address the synergistic effect of poultry and cattle production on Ozark streams in high production areas before ecological risks can be adequately addressed.     

Shape complexity of space used by American black bears influenced by sex and intensity of use

Disentangling the complexities that influence animal space use poses substantial challenges based on decision trade-offs and constraints imposed on animals. Optimal decisions suggest that the spatial complexity of home-range shapes should be inversely related to energy conservation and fitness. Hence, the most beneficial shape should be the circle. We evaluated whether shape complexity (i.e., an index of circularity) of home ranges was influenced by two extrinsic (spatial heterogeneity, preferred habitat [i.e., deciduous forest]), and three intrinsic (sex, season [breeding, non-breeding], intensity of use) factors, with intensity of use indexed as contours containing core and peripheral areas. We estimated utilization distributions of 39 radiomarked adult American black bears (Ursus americanus), a habitat generalist, using fixed-kernel techniques and estimated 50% (core area) and 95% (peripheral area) contours. We fit a set of 47 models using linear modeling and ranked models using small-sample Akaike Information Criterion. Coefficients for the best model were the intrinsic factors intensity of use (reference category = core; 0.118; 95% CL = 0.064–0.173), sex (reference = female; 0.105; 95% CL = 0.043–0.167), and intercept (0.229; 95% CL = 0.186–0.272). Shape complexity was less for core areas than peripheral areas and less for females than males. Considering complex resource selection patterns within a fragmented landscape, both sexes appeared to use energy-maximizing strategies, although the increase in shape complexity for males may be an allometric relationship based on size dimorphism. Our approach supported the phenomenon of optimality as manifested through home-range shape complexity, but we suggest that assessment of this phenomenon for habitat specialists may yield different results, including the potential importance of intrinsic factors based on more restrictive limiting factors.     

Limits to sustainable energy budget during lactation in the striped hamster (Cricetulus barabensis) raising litters of different size

A female animal appears to approach an upper limit to the rate of sustained energy intake/metabolic rate (SusEI/MR) during lactation. However, different species of animals may respond differently to the sustainable limit. Here, we measured energy budget during lactation in female striped hamsters raising litters of natural size (Con), and females whose litter size was manipulated during early lactation to support fewer or more pups (minus pups, MP or plus pups, PP). The striped hamsters significantly decreased their body mass and increased food intake from early to late lactation; and MP females had lower weight loss and food intake than the control and PP females. Litter size of the PP group decreased significantly over the period of lactation, and pups were weaned at a similar weight to that of the controls. MP females supported a significantly lower litter mass throughout lactation compared with the control and PP females, but during late lactation the pups from the MP group were significantly heavier. Resting metabolic rate (RMR) did not differ significantly between the three groups and the gross energy intake during peak lactation was 5.0×, 4.2× and 5.0 × RMR for the control, MP and PP females, respectively. Female striped hamsters reached a plateau in food intake at around 14 g/d during peak lactation, which might signify a limit of SusEI at 5.0 × RMR. However, it was not possible to determine whether the limitation on SusEI was imposed centrally by the capacity of the gastrointestinal tract to process food, peripherally by the capacity of the mammary gland to produce milk, or by the capacity of animals to dissipate heat.     

Distribution and ecology of the assemblages of myxomycetes associated with major vegetation types in Big Bend National Park,USA

The distribution and ecology of the assemblages of myxomycetes associated with four different microhabitats were studied in Big Bend National Park in Texas. During Mar. 2005, twelve plots (30 × 30 m) were established along an elevational gradient that extended from 564 to 1807 m. Samples of aerial bark from dead and living trees, aerial litter (dead but still attached plant parts), ground litter (fallen dead plant parts) and ground bark (fragments of fallen bark) were collected from these plots, which encompassed all of the major vegetation types found in the Park. Four hundred forty-seven moist chambers were prepared, and 95.8 % (428) produced some evidence (either fruit bodies or plasmodia) of myxomycetes. A total of 71 species were recorded, with ground litter yielding most (45 species). Aerial litter, aerial bark and ground bark yielded 44, 39 and 37 species, respectively. Species abundance distribution measures (diversity, dominance and similarities) varied among the four microhabitats as well as among the major vegetation types. Canonical Correspondence Analysis (CCA) showed that species distribution patterns were closely related to: (1) the major environmental-complex gradients associated with differences in elevation/temperature/moisture conditions that occur from one locality to another; and (2) the different types of microhabitat.     

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.     

Trophic ecology of the Grey Wagtail Motacilla cinerea before and during the breeding season in the region of Bejaia (Algeria)

The diet composition of the Grey Wagtail Motacilla cinerea of the Babor Range is followed by analysis of faecal samples (90 faeces) before and during the breeding season 2010. The Grey Wagtail's diet varies depending on the stage of the breeding cycle at the southern edge of their breeding area in North Africa (Bejaia). The diet consists predominantly of aquatic preys (51.79%), with Coleoptera being the most frequent constituent (n = 331, 45.5%). During the pre-laying period (February–March), the diet was variable (91 prey-taxa and H’ = 3,36 bits) and preys of medium size (5 to 8 mm) were most common. During the incubation period (April–May), preys were mainly aquatic (60%) and larger (20 to 32 mm). At the end of the breeding season (June–July), there was a greater occurrence of terrestrial preys (31 aquatic versus 30 terrestrial taxa).     

Effects of experimental warming and nitrogen enrichment on leaf and litter chemistry of a wetland grass,Phragmites australis

As global climate is warming and the nitrogen cycle accelerates, plants are likely to respond not only by shifting community composition, but also by adjusting traits such as tissue chemistry. We subjected a widespread wetland plant, Phragmites australis, to increased nitrate supply and elevated temperature in enclosures that were established in a littoral permanently submerged freshwater marsh. The nitrogen (N) and phosphorus (P) concentrations in green leaves ranged from 11.4 to 13.8 mg N and from 1.5 to 2.0 mg P g⁻¹ dry mass. While the N concentration changed little in brown litter, the P concentration decreased to 0.53–0.65 mg P g⁻¹ litter dry mass. Neither experimental warming of the water and sediment surface, nor nitrate enrichment during the growing season affected nitrogen or phosphorus concentrations in green leaves. Concentrations of the two major structural carbon compounds in plant litter, cellulose and lignin, were also unaffected, ranging from 32.1 to 34.2% of dry mass for cellulose and from 16.3 to 17.7% of dry mass for lignin. Warming, however, significantly increased the nitrogen concentration of fully brown leaf litter. Thus, temperature appears to be more important than the supply of dissolved N in the water, especially in affecting leaf litter N concentrations in P. australis, even when only water but not air temperature is increased. This result may have implications for decomposition processes and decomposer food webs, which both depend on the quality of plant litter.     

Population density and abundance of sympatric large carnivores in the lowland tropical evergreen forest of Indian Eastern Himalayas

Low density occurrence of large carnivore species and direct hunting of predators and prey make carnivore conservation complex. Vital baseline information on population status of large carnivores is still deficient in most forests of eastern Himalaya, which are known to be the biodiversity hotspots. To fill this information gap, we estimated the large carnivore population status and abundance in an intricate eastern Himalayan lowland tropical forest in Pakke Tiger Reserve, Arunachal Pradesh. Population status and abundance estimates of tigers and leopards were made through individual identification using closed capture-recapture sampling. To estimate the dhole abundance photographic encounter rate was used. For individually non-identifiable species photographic rate seemed to correlate well with animal abundance. The estimated tiger and leopard density through 1/2 MMDM was 2.14 ± 0.04/100 km² and 2.99 ± 1.13/100 km² respectively. Maximum likelihood estimates shows density of tiger 1.86 ± 0.7 and for leopard 2.82 ± 1.2.The estimated dhole abundance was (N) 10.6 ± 0.94, and density 6.62 ± 0.58 individuals in 100 km². Further, occupancy estimation of large carnivores may be tried along with assessing the comparative efficacy of other population estimation methods to establish better monitoring methods for this region.     

Factors affecting otter (<Emphasis Type="Italic">Lutra lutra</Emphasis>) abundance and breeding success in freshwater habitats of the northeastern Iberian Peninsula

Otters are elusive semi-aquatic mammals, occurring in low densities and difficult to count. A study was conducted in 15 stretches (10–12 km) of four tributaries of the Ebro River, with the aims to understand spatial and temporal changes in otter abundance and breeding success and the causes of such variations. Between 1990 and 2009, both otter parameters were assessed by means of visual spring–early summer censuses, carried out by sets of observers located every 500 m. A total of 134 censuses were carried out, involving 4,540 twilight watches (7,896.5 h) and 520 otter sightings were recorded. Also, 39 different habitat characteristics (including prey species) were established for each stretch. Otter abundance was assessed by means of three indexes related to the census effort and the length and surface units (in terms of otter habitat). Excluding the upper stretches, we found on average 0.07–0.26 adult and subadults per kilometre (1.45–6.26/km²). Important interannual fluctuations in otter abundance and breeding success were found in some Pyrenean stretches located downstream of a large reservoir. This was linked to the effect of autumn floods (in part due to the opening of dams) on the fish stocks (mainly Barbels). Similar habitat conditions resulted in similar abundances between stretches, and different habitat conditions generated different abundances in adjacent stretches of the same river. No significant differences were found for litter size between small cubs (1.60 ± 0.70 cubs per litter) and large cubs (1.39 ± 0.50) as a whole, but differences between stretches were found. On average we found between 0.009 and 0.130 large cubs per year per kilometre. Otters bred more successfully in stretches with higher otter densities. Otter abundance and breeding success correlated negatively with altitude as a consequence of the interaction of several habitat characteristics with altitude. The stepwise linear regression linked the number of adult otters per kilometre with the ecosystem production (chlorophyll a concentration), while the number of large cubs per kilometre per year was linked with the food (fish + crayfish) abundance. The findings bring about a consistent and congruent scenario of otter abundance and breeding success explained by the different steps along the food chain.     

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.     

Reproductive characteristics of female Bengal tigers,in Ranthambhore Tiger Reserve,India

Reproductive characteristics of tigers (Panthera tigris) are important to understand population viability. We studied the reproductive parameters of female Bengal tigers (P. t. tigris) in a dry, tropical, deciduous habitat in Ranthambhore Tiger Reserve (RTR), western India, from April 2005 to March 2010. We monitored tigers by direct observation and with cameras placed throughout their habitat. The potential breeding population included 13 adult females. The average age at first reproduction was 3.3 years; 34 cubs were born during the study period (6.2?±?0.82 per year). Sixty-six percent of the births occurred between October and December. Mean litter size was 2.26?±?0.52 (n?=?13, range?=?1–3). The sex ratio of 32 cubs was 1.29 M:1.00 F. The survival rate of cubs (<12 months) was 85 % (95 % CI?=?0.68–0.94), whereas that of juveniles (12–24 months), and subadults (24–36 months) was 79 % (95 % CI?=?0.61–0.91). All breeding females were >3 years old. Only 2 of the 13 females reproduced twice during the 5 years of the study. The birth interval was 33.4?±?3.7 months (range 24–65 months). The mean reproductive rate was 0.59?±?0.23 cubs/female/year. Our study indicates that tiger populations can grow rapidly if the habitat provides adequate protection, an adequate population of prey, and minimal to no poaching.