Hibernation Period Research Articles

Nesting behaviour and seasonal body mass changes in a rural Irish population of the Western hedgehog (Erinaceus europaeus)

There was previously no information on nesting, seasonal body mass or the hibernation behaviour of the hedgehog in Ireland. Between 2008 and 2009, hedgehogs were caught, weighed weekly and monitored by radio tracking at a rural Irish site. Day nests were recorded in the active period and hibernacula thereafter. Arable land has been reported to be poorly utilised by hedgehogs in the UK and Denmark. In Ireland, day nests and hibernacula were constructed in the hedgerows of arable land indicating that these areas will be exploited if hedgerow is maintained and highlights the importance of maintaining hedgerows in arable areas. Individual females returned to the same day nest significantly more than males. Over the 2 years, individuals were found to occupy a mean of 1.8 (±0.9; SD) hibernacula (maximum of 3) and they rotated between nests up to four times (mean of 2.5 ± 1.6). When hedgehogs occupied multiple hibernacula, those occupied in mid winter (December and January) were occupied for significantly longer than those occupied at the start (October and November) and end (February and March) of hibernation. Studies in the UK and Denmark have reported on hedgehog hibernation. However, the winter climate in southern Ireland is milder than other areas of Europe and thus it was expected that hibernation characteristics would also differ, i.e. shorter hibernation periods, earlier emergence, lower body mass loss and the ability to survive hibernation at a lower body mass. This proved to be the case with a mean hibernation period (±SE) of 148.9 (±0.5) days, a mean body mass loss of 17.0 (±0.53) %, emergence in March and the ability of late juveniles to survive at a pre-hibernation body mass of 475 g.

Morphofunctional changes in the small intestine epithelium of the frog Rana temporaria in the course of hibernation

The structure and function of small intestine epithelium have been studied in overwintering frogs at various stages of hibernation. Experiments on the in vitro absorption of arginine vasotocin (AVT) have shown that the epithelium ability for absorption of this nonapeptide without hydrolysis persists during hibernation. However, there is a decline in AVT absorption observed in January–February and later on (as compared with that in October–December) which is most pronounced in March–April. Changes in the epithelial structure appear by midwinter and are growing towards spring. In April–May, enterocyte height decreased by 33%, microvilli length by 40%, and number of mitochondria by 57% relative to the values at the beginning of hibernation. The absence of signs of breakdown attests to the adaptive nature of the observed changes. The dynamics of the studied parameters reveals morphological and functional plasticity of small intestinal epithelium in Rana temporaria over the hibernation period.

Food web structure in a Salix subfragilis dominated wetland in Hangang estuary using stable isotopes and fatty acid biomarkers

We investigated food webs of a Salix subfragilis-dominated wetland in the Janghang wetland in the Hangang estuary, which is very close to the Demilitarized Zone, along the west coast of Korea. Our study focused on understanding sesarmine crab (Sesarma dehaani)-related food webs in a S. subfragilis forest. For our study, we used carbon and nitrogen stable isotopes and fatty acid biomarkers. We collected samples of plants, animals, and detrital sediment from four quadrats (5×5 m2) set in the S. subfragilis community. Samples were collected from September 2006 to June 2009, except during the winter hibernation period of S. dehaani. In the wet season, the sediment showed relatively high δ13C and low δ15N signatures compared with relatively low δ13C and high δ15N signatures in the dry season. Mature S. dehaani appeared to feed on fresh leaves and other carbon sources, such as immature individuals or fish, in addition to detrital sediment, which appeared to be the main carbon source for immature crabs. Principal component analysis of fatty acid biomarkers of S. dehaani showed a clear difference between immature individuals (10–30 mm) and mature ones (larger than 30 mm), indicating that the main food source for immature crabs was detrital sediment, whereas mature crabs foraged plants in addition to consuming detrital sediment. On the basis of our results from stable isotope and fatty acid analyses, mature S. dehaani appeared to feed on detrital sediment and fresh leaves of S. subfragilis in summer in addition to engaging in cannibalism of immature individuals.

Summer and winter torpor use by a free-ranging marsupial

Torpor is usually associated with low ambient temperatures (Ta) in winter, but in some species it is also used in summer, often in response to limited food availability. Since the seasonal expression of torpor of both placental and marsupial hibernators in the wild is poorly documented by quantitative data, we investigated torpor and activity patterns of the eastern pygmy-possum Cercartetus nanus (17.4g) over two seasons. We used radio telemetry to track animals during winter (n=4) and summer (n=5) in a warm-temperate habitat and found that torpor was used in both seasons. In winter all animals entered periods of short-term hibernation (from 5 to 20days) containing individual torpor bouts of up to 5.9days. In summer, torpor bouts were always <1day in duration, only used by males and were not related to daily mean Ta. Pygmy-possums entered torpor at night as Ta cooled, and rewarmed during the afternoon as Ta increased. Individuals interspersed torpor bouts with nocturnal activity and the percentage of the night animals were active was the same in summer and winter. Our study provides the first information on torpor patterns in free-ranging C. nanus, and shows that the use of torpor throughout the year is important for energy management in this species.

Intensity of parasitic mite infection decreases with hibernation duration of the host snail

Temperature can be a limiting factor on parasite development. Riccardoella limacum, a haematophagous mite, lives in the mantle cavity of helicid land snails. The prevalence of infection by R. limacum in populations of the land snail Arianta arbustorum is highly variable (0-78%) in Switzerland. However, parasitic mites do not occur in host populations at altitudes of 1290 m or higher. It has been hypothesized that the host's hibernation period might be too long at high elevations for mites and their eggs to survive. To test this hypothesis, we experimentally infected snails and allowed them to hibernate at 4°C for periods of 4-7 months. Winter survival of host snails was negatively affected by R. limacum. The intensity of mite infection decreased with increasing hibernation duration. Another experiment with shorter recording intervals revealed that mites do not leave the host when it buries in the soil at the beginning of hibernation. The number of mites decreased after 24 days of hibernation, whereas the number of eggs attached to the lung tissue remained constant throughout hibernation. Thus, R. limacum survives the winter in the egg stage in the host. Low temperature at high altitudes may limit the occurrence of R. limacum.

Prospects for pumped-hydro storage in Germany

After a period of hibernation, the development of pumped-hydro storage plants in Germany regains momentum. Motivated by an ever increasing share of intermittent renewable generation, a variety of energy players considers new projects, which could increase the available capacity by up to 60% until the end of the decade. This paper analyzes the current development and evaluates the revenue potential as well as possible barriers. Overall, the prospects for new pumped-hydro storage plants have improved, even though profitability remains a major challenge.

Metabolism during winter in a subtropical hibernating bat, the Formosan leaf-nosed bat (Hipposideros terasensis)

The 60-g subtropical Formosan leaf-nosed bat, Hipposideros terasensis, hibernates in the wild at warm roost (and hence body) temperatures up to 23°C. For small hibernators, torpid metabolic rate is temperature dependent and thus hibernation in warm hibernacula is predicted to be energetically costly. This species, however, rarely feeds during the hibernation season to offset the expected high energetic costs. In this study we used a respirometry system to quantify physiological characteristics of euthermic and torpid H. terasensis in winter. We tested the hypothesis that H. terasensis exhibits metabolic inhibition during torpor. Our results showed that H. terasensis saved 94.6% energy by using torpor at air temperatures of 15°C, compared with its euthermic metabolic rate at that air temperature. Torpor metabolic rate declined with declining air temperature to around 14°C, but then increased at lower air temperatures of 10–14°C. Above 14°C, the slope of − 13.0°K ± 1.4°K between metabolic rates and body temperatures in an Arrhenius plot (or Q10 = 4.4) suggests that, in addition to direct temperature effects, H. terasensis exhibited metabolic inhibition during torpor. A model used to evaluate energy expenditure of H. terasensis showed that at 20°C and 23°C a 55-g bat needs 194 kJ (4.9 g fat) and 273.2 kJ (6.9 g fat), respectively, to survive a 70-day hibernation period.

Aspectos ecológicos y efectos del manejo forestal en una población de tortuga mediterránea (Testudo hermanni hermanni) en Cataluña (España)

The aim of this research was to evaluate the effects of forestry works on Testudo hermanni hermanni, and to establish ecological parameters useful for habitat management. This study took place in the northeast of Spain, in the Albera Mountains, where one of the last natural populations of Hermann’s tortoises lives. Twenty-one tortoises were weekly monitored using radiotracking during six months, between July 2009 and January 2010. Between October 2009 and January 2010, forestry works took place at the study site. The impact of the forestry works and the associated damages were estimated using two approaches: the displacements of the monitored tortoises and the use of plaster models resembling tortoises, which were placed in similar locations and conditions to live tortoises. Radiotracking results showed that 30% of the tortoises were found on open areas (pastures and sparse cork oak forest), whereas 70% corresponded to dense forests and heath scrubland locations. The analysis of the effect of forestry works showed that tortoises were affected by the works in 45% of the cases, even during hibernation period. The simulation results of the impact of the forestry works based on plaster models showed that 4% of the models were seriously damaged when using manual works (brush cutters and clearing saws), whereas mechanized works (chain tractor) were responsible for an estimation of 22% mortality and 6% serious damages.

The Panzootic White-nose Syndrome: An Environmentally Constrained Disease?

White-nose syndrome (WNS) is an emerging disease of hibernating bats probably caused by a pathogenic fungus, Geomyces destructans. The fungus has dispersed rapidly in the Northeastern United States and Canada and is presently a serious risk to hibernating bats of the mid-southern United States. Our objectives were to investigate how the environmental factors of temperature and resources impact the physiology of bats and apply this to explore possible effects of the fungus G.destructans on bats. Using a dynamic, physiologically based model parameterized for little brown bats (Myotis lucifugus), we found that the survival region defined in terms of minimal and maximal cave temperatures and bat lipid reserve levels exhibits plasticity as a function of cave temperature. During the pre-hibernation period, constellations of increased availability of fall and winter prey, reduced energy expenditure and lipogenic factors provide fat deposition in hibernator species that engender survival throughout the hibernation period. The model-derived survival region is used to demonstrate that small increases in lipid reserves allow survival under increasing maximum temperatures, which provides flexibility of bat persistence at the higher cave temperature ranges that may occur in the Southern United States. Antipodally, the lower-temperature survival range is bounded with minimum temperatures. Our results suggest that there is an environmental distinction between survival of bats in Southern and Northern US states, a relationship that could prove very important in managing WNS and its dispersal.

Survival rates in a small hibernator, the edible dormouse: a comparison across Europe

Understanding how local environmental factors lead to temporal variability of vital rates and to plasticity of life history tactics is one of the central questions in population ecology. We used long-term capture-recapture data from five populations of a small hibernating rodent, the edible dormouse Glis glis, collected over a large geographical range across Europe, to determine and analyze both seasonal patterns of local survival and their relation to reproductive activity. In all populations studied, survival was lowest in early summer, higher in late summer and highest during hibernation in winter. In reproductive years survival was always lower than in non-reproductive years, and females had higher survival rates than males. Very high survival rates during winter indicate that edible dormice rarely die from starvation due to insufficient energy reserves during the hibernation period. Increased mortality in early summer was most likely caused by high predation risk and unmet energy demands. Those effects have probably an even stronger impact in reproductive years, in which dormice were more active. Although these patterns could be found in all areas, there were also considerable differences in average survival rates, with resulting differences in mean lifetime reproductive success between populations. Our results suggest that edible dormice have adapted their life history strategies to maximize lifetime reproductive success depending on the area specific frequency of seeding events of trees producing energy-rich seeds.

Thermal energetics and torpor in the common pipistrelle bat, Pipistrellus pipistrellus (Vespertilionidae: Mammalia)

Rate of metabolism and body temperature were studied between −6°C and 38°C in the common pipistrelle bat Pipistrellus pipistrellus (Vespertilionidae), a European species lying close to the lower end of the mammalian size range (body mass 4.9±0.8g, N=28). Individuals maintained only occasionally a normothermic body temperature averaging 35.4±1.1°C (N=4) and often showed torpor during metabolic runs. The thermoneutral zone was found above 33°C, and basal rate of metabolism averaged 7.6±0.8mLO2h−1 (N=28), which is 69% of the value predicted on the basis of body mass. Minimal wet thermal conductance was 161% of the expected value. During torpor, the rate of metabolism was related exponentially to body temperature with a Q10 value of 2.57. Torpid bats showed intermittent ventilation, with the frequency of ventilatory cycles increasing exponentially with body temperature. Basal rate of metabolism (BMR) varied significantly with season and body temperature, but not with body mass. It was lower before the hibernation period than during the summer. The patterns observed are generally consistent with those exhibited by other vespertilionids of temperate regions. However, divergences occur with previous measurements on European pipistrelles, and the causes of the seasonal variation in BMR, which has only rarely been searched for among vespertilionids, remain to be examined.

Increasing bat abundance in a major winter roost in central Poland over 30 years

Abstract A bat census in the years 1981–2010 (repeated twice during each hibernation period in January and March) showed upward trends in many populations of bats hibernating in the Szachownica Cave (central Poland). Total numbers of the bat assemblage, which consisted of 11 species, increased within the study period from 178 to 1477 individuals in the first decade to 835–2902 in the past decade of the study, with the highest rates of increase noted in Barbastella barbastellus, Plecotus auritus and Myotis nattereri. Myotis myotis and Myotis daubentonii showed only slight upward trends. In the years 2009–2010, Myotis bechsteinii occurred in markedly higher numbers (up to 24 individuals) as compared to previous years.

Taphonomic modifications produced by modern brown bears (Ursus arctos)

ABSTRACTActualism has been a fundamental tool in taphonomy. The knowledge of accumulation patterning of modern faunal allows us to interpret the activity of different actors in the archaeological record and to reconstruct the behaviour of preterit animals and humans in which we are interested. However, until now, there are few works that include bone modifications made by bears amongst those made by carnivores.Most data about bone modifications made by bears have been obtained from the archaeo‐palaeontological record. In most of these assemblages, the presence of bears is related to their period of hibernation. Therefore, in these contexts, the changes documented on recovered bear bones are associated only with cannibalism.In this paper, we present an actualistic study about modifications on bones made by modern brown bears. These animals can cause damage similar to those produced by other large carnivores. Generally, bear activity leaves slight damage, mainly on large‐sized animal bones. However, on bones of small‐sized animals and those of greater fragility, the bears can produce abundant damage. Though not usual, bears can break long bones and consume the complete epiphysis. This study suggests that bears have the potential to be agents of bone modification in fossil assemblages. Consequently, they should be considered as a possible agent of modification of faunal remains in the fossil record. Copyright © 2011 John Wiley &amp; Sons, Ltd.

Prospects for Pumped‐Hydro Storage in Germany

After a period of hibernation, the development of pumped‐hydro storage plants in Germany regains momentum. Motivated by an ever increasing share of intermittent renewable generation, a variety of energy players considers new projects, which could increase the available capacity by up to 60% until the end of the decade. This paper analyzes the current development and evaluates the revenue potential as well as possible barriers. Overall, the prospects for new pumped‐hydro storage plants have improved, even though profitability remains a major challenge.

A Survival Estimate of Midwestern Adult Eastern Box Turtles Using Radiotelemetry

Abstract Eastern box turtles (Terrapene carolina carolina) are widespread in U.S. eastern deciduous forests, yet many populations are experiencing dramatic declines. Herein, we present an assessment of annual survival for adult eastern box turtles that were radio-tracked over a period of 2 y. Using a known fates Kaplan-Meier estimator, the baseline annual survival estimate for adult eastern box turtles in Indiana's south-central region is 96.2%. Annual survival rates varied slightly between the hibernal period (95.6%) and the active period (96.7%). These initial data provide wildlife managers with a baseline from which a recovery period can be calculated. In areas where road mortality and human interface are high, this estimate should be adjusted to ensure the time for recovery is adequate. Further research is recommended over generations and age-classes to better inform management of this protected species.

Energy homeostasis regulatory peptides in hibernating grizzly bears

Grizzly bears ( Ursus arctos horribilis) are inactive for up to 6 months during hibernation. They undergo profound seasonal changes in food intake, body mass, and energy expenditure. The circa-annual regulation of metabolism is poorly understood. In this study, we measured plasma ghrelin, leptin, obestatin, and neuropeptide-Y (NPY) levels, hormones known to be involved in the regulation of energy homeostasis, in ten grizzly bears. Blood samples were collected during the active summer period, early hibernation and late hibernation. Plasma levels of leptin, obestatin, and NPY did not change between the active and the hibernation periods. Plasma total ghrelin and desacyl-ghrelin concentrations significantly decreased during the inactive winter period compared to summer levels. The elevated ghrelin levels may help enhance body mass during pre-hibernation, while the low plasma ghrelin concentrations during hibernation season may contribute to the maintenance of hypophagia, low energy utilization and behavioral inactivity. Our results suggest that ghrelin plays a potential role in the regulation of metabolic changes and energy homeostasis during hibernation in grizzly bears.

Sedimentation and sediment characteristics in sea cucumber Apostichopus japonicus (Selenka) culture ponds

Annual sedimentation, re-suspension rates and contents of particulate organic carbon (POC), particulate organic nitrogen (PON) and total phosphorus (TP) in the sediment were investigated in two sea cucumber culture ponds at Rongcheng, Shandong Province, China. The results showed that the average flux of total particulate matter in the ponds was 22.1 g m2 d−1. The average re-suspension rate of the sediment in the ponds was 81.7%. The re-suspension rates in spring and autumn were higher than those in summer and winter. The mean contents of POC, PON and TP in the sediment of the ponds were 4.4, 0.5 and 0.6 (mg g−1), respectively, and the mean contents of Chlorophyll a (Chl a) and pheophytin in the sediment were 8.1 and 12.1 μg g−1 respectively. The POC, PON and TP contents in the sediment of the ponds increased during the period of sea cucumber aestivation (summer) and hibernation (winter), while they decreased during the feeding periods. The organic matter accumulation rate and the contents of POC, PON, TP, Chl a and pheophytin in the sediment were even lower than those in the pond without sea cucumber (P<0.05). The results demonstrated that sea cucumber culture can effectively stop nutrient accumulation at the bottom of the cucumber culture ponds.

Ecological aspects of bat hibernacula in temperate climate zone of Central Europe

Ecological aspects of bat hibernacula in temperate climate zone of Central Europe In temperate climate zone, undergrounds (caves) are the main place for bat hibernation. It is possible to distinguish three kinds of usage of caves by bats: caves used as a hibernaculum, where bats spend the winter period, caves used as shelters for reproductive colonies during the summer period, and caves used as temporary shelters during transitional period (spring and fall) and also as places for food. Caves used as hibernaculum must offer a suitable microclimate for bats. Several important physical factors decide on the selection by bats of a refugee for a period of hibernation. The hibernaculum should have a zone of total darkness. During hibernation bats pay special attention to air circulation, humidity and temperature. These factors are also of significance in forming the microclimate condition inside cave system. Throughout the influence above mentioned factors, a connection between microclimatic condition and topoclimate appears in the cave system and, as a consequence, a refugioclimate forms.

Результати обліку кажанів Національного природного парку «Подільські Товтри» на зимівлі 2008 року

Результати обліку кажанів Національного природного парку «Подільські Товтри» на зимівлі 2008 року

Seasonal flexibility in organ size in the Andean lizard Liolaemus moradoensis

The understanding of animal functioning in fluctuating environments is a major goal of physiological and evolutionary ecology. In temperate terrestrial habitats, one of the most pervasive changes in environmental conditions is that associated with the seasonal change along the year. In this study, we describe the pattern of seasonal variation in the size of nine internal organs in the lizard Liolaemus moradoensis from the Andes Mountains of Central Chile. We observed that the size of digestive organs was greater during summer in comparison to other seasons. Dry masses of liver and fat bodies reached maximum values during summer and minimum during spring. We suspect that lowest spring values are related with build-up costs of energetically expensive organs (e.g., digestive, muscle mass) at the end of the hibernation period. Dry mass of the heart and lungs did not show a clear pattern of variation, suggesting that cardiac and pulmonary performance were maintained throughout the year. The dry mass of kidneys was greater during winter than during summer, a result observed in other hibernating lizards but for which there is no clear explanation. Finally, the dry mass of testes showed a maximum value during autumn and a progressive reduction toward summer, indicating that reproduction occurs during autumn. When represented in a bivariate space, acquisition (digestive), distribution (heart, lungs and kidneys), storage (liver and fat bodies), and expenditure (testes) organs generate four clusters. In general terms, observed seasonal pattern of change in organ size is in agreement with those reported for other lizard species that inhabit highly fluctuating environments.