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1.
The seasonal home range size and spatial relationships of 16 adult genetsGenetta genetta Linnaeus, 1758 (6 males and 10 females) were estimated in a Mediterranean habitat of northeastern Spain. Genets minimum density was estimated as 0.98/km2. Mean annual home range was 113.1 ha in males and of 72.0 ha in females. Males had larger home ranges than females in all seasons, but differences were only significant in winter. Home range size changed seasonally and showed a similar pattern in both sexes, with lower values in summer (males — 41.2 ha, females — 29.0 ha) and maximum ones in spring (males — 78.8 ha, females — 56.1 ha). Animals displayed spatial fidelity throughout the year. Core areas (MCP50) represented 27% and 19% of total home range size for males and females, respectively. Resting home ranges (based on locations of inactive animals) were 9 times lower than overall home range size. Individuals of the same sex overlapped less than individuals of different sexes, especially with regard to core areas, which showed almost no overlap. The results obtained suggest that (1) different factors are likely to affect the space use of genets, such as body mass, food abundance and reproductive cycle; (2) genets use space in a heterogeneous way, with areas of greater activity than others within their home range; (3) there was intrasexual segregation with regard to space use.  相似文献   

2.
Livestock grazing and the collection of bamboo shoots are the main threats to giant panda (Ailuropoda melanoleuca) habitat in the Liangshan Mountains in China. It is important to clarify the effect of these disturbances to the giant panda to formulate targeted management policies. Based on species distribution models and daily activity models, we investigated the effects of livestock grazing and bamboo shoot collection on giant pandas from May 2021 to July 2022. Our results indicated the giant panda's suitable habitat in the reserve covered 51.83 km2 (15.02% of the reserve area). Grazing and bamboo shoot collection led to losses of 19.08 km2 and 7.68 km2 of suitable habitat, respectively. Together, the 2 activities resulted in a loss of 28.35 km2 of suitable habitat, which was more than half of the area of panda habitat. The areas of suitable habitat for giant pandas significantly overlapped with the areas affected by both disturbances. Giant pandas did not show significant differences in daily activity rhythms under a single disturbance, but the daily activity rhythms of giant pandas differed when we compared the area combining the 2 disturbances with the undisturbed area. Our study reveals that the anthropogenic disturbances in the reserve have varying effects on the suitable habitat range and daily activity rhythm of giant pandas and evidence of a synergistic effect. Therefore, when formulating relevant conservation policies, it is important to fully evaluate the extent and characteristics of anthropogenic disturbances in shaping the population distribution and habitat preferences of the giant panda and other wildlife to enhance the efficacy of conservation management practices.  相似文献   

3.
We examined vervet monkey (Chlorocebus pygerythrus) space use using GPS/UHF telemetry data from 10 vervet monkeys across six troops over 9 months within a 420 ha suburban eco‐estate. We documented a mean home range of 0.99 km2 (95% MCP) and 1.07 km2 (95% KDE) for females (n = 6), 1 km2 (95% MCP) and 1.50 km2 (95% KDE) for males (n = 4) and 0.87 km2 (95% MCP) and 1.12 km2 (95% KDE) for troops (n = 6), respectively, indicating that males and larger troops had larger home ranges. These relatively small home ranges included shared territorial boundaries and high home range overlap. Vervet monkey movements indicated higher morning activity levels, and habitat selection indicated significantly more use of golf course, urban residential and forest, thicket and woodland areas, and avoidance of wetland, grassland and shrub, and urban built‐up areas. Our results suggest that modified habitat use by vervet monkeys is a consequence of behavioural facilitation to access highly available food resources, thereby facilitating their persistence in green spaces in urban areas of South Africa. Conflict management is dependent on the conservation of sufficient natural habitats and food resources, to minimise their dependence on anthropogenic supplementary food resources and consequently reduce human–monkey conflict.  相似文献   

4.
Daily ranges of 19 (6 males, 13 females) adult red deerCervus elaphus Linnaeus, 1758 were studied using 24-h tracking sessions in Białowieża Primeval Forest (BPF), Poland, from 2001 to 2004. Overall, size of mean (± SE) daily ranges was larger for males (1.22 ± 0.10 km2) than females (1.00 ± 0.09 km2), although the difference was not significant. Similarly, mean daily ranges were 6–46% larger for males than females in each season, although there were no statistical differences in mean daily ranges among seasons for each sex. Abiotic factors, especially temperature, significantly affected daily ranges of females, but not males, suggesting sexual differences in response to weather variables. On a daily basis, males used 3% of their annual home range, whereas females used 12% of their annual home range, indicating females used their annual home ranges more intensely than males. Consecutive daily ranges overlapped little for each sex. Daily ranges of red deer in BPF were considerably larger than previously reported in Europe, suggesting factors unique to BPF also influenced size of daily ranges.  相似文献   

5.
Space use and territoriality influence population structure and dynamics and is therefore an important aspect in understanding the ecology of animals. We investigated spatial and temporal space use of wolverines (Gulo gulo) in northern Scandinavia. We estimated home ranges of 24 radio-marked individuals (17 females and seven males). Male home ranges (mean 669 km2; SE = 211) were significantly larger than female home ranges (mean 170 km2; Wilcoxon–Mann–Whitney; P = 0.001) and encompassed or included parts of up to five different females. Home range sizes of reproducing (170 km2; SE = 51) and barren (171 km2; SE = 63) adult females did not differ. Wolverines in Scandinavia exhibit intrasexual territoriality, with male home ranges totally exclusive and female home ranges either exclusive or with little home range overlap. Overlap between wolverine territories is most likely explained by intrasexual tolerance and kinship.  相似文献   

6.
When animal home ranges overlap extensively in species lacking overt territorial behaviours, identifying exclusive core areas within individual ranges can be difficult. By analysing the size and overlap of successively smaller core areas among individual Eurasian red squirrels (Sciurus vulgaris), we determined exclusive areas within the home ranges of resident males and females. Possible effects of habitat composition and food supplies were explored by monitoring squirrels in different conifer forests and during years with low and high tree seed production. Using outlier-exclusive cores (OEC) revealed that the total ranges consisted of large sally zones (on average, 35% of the total minimum convex polygon [MCP] range) around home ranges with multi-nucleate cores. The mean OEC home range size did not differ between the sexes but was larger with poor food availability. Home ranges (99% incremental cluster polygons [ICP]) overlapped extensively between sexes (average overlap high food–low food: males by females 21–40%, females by males 43–45%) and among males (males by males 26–44%), while intrasexual overlap among females was low (9–10%). The overlap of inner cores among females rapidly approached zero, suggesting the intrasexual territoriality of 75% core areas. This was not the case among male squirrels, for which intrasexual overlap averaged only 4% at 50% but 18% at 75% core areas. Even the smallest inner cores had some degree of intersexual overlap, indicating that complete territoriality did not occur in this species. Female home ranges were more strongly affected by annual fluctuations in food supplies than male ranges. Females reduced the size of their food-based intrasexual territories when food availability increases. Males probably benefit from using larger home ranges and core areas, which overlap with the ranges of several females, by increasing their probability of successful mating.  相似文献   

7.
We studied factors affecting density and spacing patterns in the pine marten Martes martes population inhabiting temperate forests of Bia?owieza National Park, eastern Poland. From 1985/1986 to 1995/1996 marten densities ranged from 3.63 to 7.57 individuals 10 km?2 (mean 5.4) and were positively correlated with abundance of forest rodents in the previous year. The rate of marten population growth was inversely density‐dependent and positively related to rodent density. Annual mortality rate averaged 0.384 and tended to be negatively related to marten densities. Mean annual home range of males (2.58 km2, SE=0.24) was larger than that of females (1.41 km2, SE=0.20). Seasonal home ranges also differed significantly between males and females. Both sexes held the smallest ranges in December–January. Female ranges increased in April–May, whereas those of males increased in June–September when they were mating. Fidelity of pine martens to their home ranges was very high. The mean shift between arithmetic centres of seasonal ranges was 0.25 km, and the ranges recorded in two consecutive seasons overlapped, on average, by 87–90%. We observed very little home range overlap between neighbouring male (mean 4–6%) or female (mean 6%) marten. Year round the neighbouring individuals of the same sex neither avoided nor attracted each other. Females attracted males only during the spring‐summer mating season. A review of other studies has documented that winter severity and seasonal variation in ecosystem productivity were essential factors shaping the biogeographic variation in pine marten densities between 41o and 68oN. The density of marten populations increased in areas with mild winters and lower seasonality. Maximum population densities (indicative of habitat carrying capacity) were correlated with mean winter temperature. In Europe, male home ranges increased with decreasing forest cover in a study area, whereas female ranges varied positively with rodent abundance.  相似文献   

8.
Territorial activity was studied using satellite tracking of four brown bears (Ursus arctos) in Kamchatka in 2005–2006 and three brown bears on Sakhalin in 2011–2012. The size of annual home ranges was 6.09–27.58 km2 for females and 153.12 km2 for males. The size of the nuclear zone of the annual home ranges did not exceed 1.68 km2. Seasonal home ranges were largest in August-September and smallest in May. The home ranges of two females in Kamchatka were significantly overlapped, the lesser degree of overlap was noted for two females on Sakhalin. The nature of the use of the study area by bears, essentially depends on the seasonal distribution of food, in particular salmon.  相似文献   

9.
Abstract: Historically, bobcats (Lynx rufus) were found throughout the Corn Belt region, but they nearly disappeared from this area due to habitat loss and unregulated harvest that occurred during the century after European settlement. Reports of bobcat occurrences have been increasing in Iowa, USA, and biologists would like to understand the mechanisms enabling bobcats to recolonize this fragmented agricultural landscape. We determined space use and habitat selection of bobcats by radiocollaring 68 bobcats in south-central Iowa during 2003–2006. We triangulated 12,966 locations and recovered an additional 1,399 3-dimensional locations from Global Positioning System collars. We used a fixed kernel estimator to calculate 95% utilization distributions (UDs) for home ranges and 50% UDs for cores. Annual home range area of males (x̄ = 58.6 km2, 95% CI = 49.2–69.9) was nearly 3 times that of females (x̄=19.9 km2, 95% CI = 17.0–23.3). Females used smaller home ranges during April-September when they were suspected to have kittens with them (x̄ = 16.8 km2, 95% CI = 13.7–20.7), as compared to October-March (x̄ = 24.1 km2, 95% CI = 19.0–30.7), whereas home ranges of males did not differ between seasons. Similarly, core area of males (x̄ = 7.7 km2, 95% CI = 6.2–9.6) was larger than that of females (x̄ = 2.3 km2, 95% CI = 1.9–2.7). Females used significantly smaller cores in April-September (x̄ = 1.8 km2, 95% CI = 1.4–2.3) as compared to October-March (x̄ = 2.8 km2, 95% CI = 2.2–3.7), whereas males did not. For both sexes, compositional analysis indicated that forest habitat was ranked higher than all other habitat classes at both the landscape and local scale. Standardized habitat selection ratios illustrate that female and male bobcats selected forest habitat about twice as frequently as any other habitat class, including grassland and Conservation Reserve Program land. Predictive models indicated that home range and core area was smaller in landscapes where perennial forest and grassland habitats were less fragmented. Predictive models indicated home ranges were more irregular in shape in landscapes where row crop patches were less aggregated within home ranges. Our results have practical implications for wildlife managers regarding expected bobcat habitat use and distribution as the species becomes more abundant in the agricultural landscape of the Midwest.  相似文献   

10.
This study examined sex‐specific differences in home range size of adult Indo‐Pacific bottlenose dolphins off Bunbury, Western Australia. We applied a new kernel density estimation approach that accounted for physical barriers to movements. A Bayesian mixture model was developed to estimate a sex effect in home range size with latent group partitioning constrained by association data. A post hoc analysis investigated group partitioning relating to the proportion of time spent in open vs. sheltered waters. From 2007 to 2013, photographic‐identification data were collected along boat‐based systematic transect lines (n = 586). Analyses focused on adult dolphins of known sex (sighted ≥ 30 times; n = 22 males and 34 females). The 95% utilization distributions of males varied between 27 and 187 km2 (; 94.8 ± 48.15) and for females between 20 and 133 km2 (65.6 ± 30.9). The mixture model indicated a 99% probability that males had larger home ranges than females. Dolphins mostly sighted in open waters had larger home ranges than those in sheltered waters. Home ranges of dolphins sighted in sheltered waters overlapped with areas of highest human activity. We suggest that sex differences in home ranges are driven by male mating strategies, and home range size differences between habitats may be influenced by prey availability and predation risk.  相似文献   

11.
Home range and habitat use of the sable Martes zibellina brachyura were studied in a cool-temperate mixed forest in northernmost Japan. In both sexes, some sables showed a wide range of migration without establishing home ranges and the others had home ranges of 0.50–1.78 km2 (mean: 1.12±SD 0.495 km2, n =6) which were not significantly correlated with body weight or age. The analysis of canine tooth annuli revealed that the maximum age was 5.5 years. The home ranges of some sables overlapped so extensively that the home ranges and even the core areas did not appear exclusive to other sables. We determined resting sites and foraging routes in snow in winter. Comparison of vegetation at the resting sites and foraging routes with habitat availability suggested that the sables preferred resting in dense-tree forests with many tree species and debris probably in order to avoid predators (red foxes) and strong wind and foraging in forests of climax succession which are usually rich in their prey such as voles and mice.  相似文献   

12.
Fencing conservation areas is ubiquitous in South Africa, however, the impact of these on predator ecology has not been tested. We used relationships between prey abundance and predator space use to create equations to predict the home range size of lions Panthera leo and leopards Panthera pardus. We then successfully tested these predictions using published data (Phinda, Makalali) and home range estimates from radio collared individuals reintroduced to Addo Elephant National Park. Spotted hyaena Crocuta crocuta ranges also seem food dependent. Lion home ranges in Addo (114 ± 5 km2) required 180 fixes to be accurately estimated, spotted hyaena ranges (91 ± 10 km2) required 200 fixes, and the solitary leopard had 295 fixes for a range of 38 km2. There were no sexual differences in home range sizes of lions or hyaenas. The daily food intake rate of lions, measured during continuous follows, was 9.8 kg per female equivalent unit. Dominant male lions (14.3 km for 8.3 kg) traveled furthest but obtained the least amount of food per day compared to subordinate males (8.9 km for 16.0 kg) and females (5.8 km for 17.9 kg). Subordinate males traveled the fastest and during the day, to avoid competition and harassment from the dominant males. From an evolutionary viewpoint, the use of fences for conservation has not affected the natural behaviour of the predators as they still conform to predictions derived from unfenced reserves; that is, prey abundance is the key factor in determining space use of large predators.  相似文献   

13.
In ecosystems with seasonal fluctuations in food supply many species use two strategies to store food: larder hoarding and scatter hoarding. However, because species at different geographic locations may experience distinct environmental conditions, differences in hoarding behavior may occur. Tree squirrels in the genus Tamiasciurus display variation in hoarding behavior. Whereas red (Tamiasciurus hudsonicus) and Douglas's (Tamiasciurus douglasii) squirrels in mesic coniferous forests defend territories centered around larder hoards maintaining non‐overlapping home ranges, red squirrels in deciduous forests defend small scatter‐hoarded caches of cones maintaining overlapping home ranges. As in other rodent species, variation in hoarding behavior appears to influence the spacing behavior of red and Douglas's squirrels. In contrast, Mearns's squirrels (Tamiasciurus mearnsi) in xeric coniferous forests neither rely on larder hoards nor appear to display territorial behavior. Unfortunately, little is known about the ecology of this southernmost Tamiasciurus. Using radiotelemetry, we estimated home‐range size, overlap, and maximum distance traveled from nest to examine the spacing behavior of Mearns's squirrels. Similar to scatter‐hoarding rodents, maximum distance traveled from nest was greater for males during mating season, whereas those of females were similar year round. Although no seasonal differences were detected, male home ranges were three times larger during mating season, whereas those of females were smaller and displayed a minor variation between seasons. Home ranges were overlapped year round but contrary to our expectations, overlap was greater during mating season for both sexes, with no detectable relationship between male home‐range size and the number of females overlapped during mating season. Overall, the results appear to support our hypothesis that in the absence of larder hoards, the spacing behavior of Mearns's squirrels should be different from larder‐hoarding congeners and more similar to scatter‐hoarding rodents.  相似文献   

14.
We describe the population structure and ranging patterns of a troop of Sichuan snub-nosed monkeys (Rhinopithecus roxellana) based on a study conducted between November 2002 and November 2003 in Zhouzhi National Nature Reserve, Shaanxi Province, China. The troop comprised several 1-male units and an all-male unit. Opportunistic censuses revealed that there were ≥112 individuals in the troop. The adult sex ratio (male vs. female) was 1:3.7. The ratios of adults to immatures and infants to adult females were 1:0.7 and 1:2, respectively. Via a grid system, we estimated the home range of the troop to be 18.3 km2, of which 7.4 km2 was the core area. The subjects exhibited distinct seasonal ranging patterns. Their movement across the home range was extensive in spring and restricted in autumn. In addition, reuse of quadrats was highest in winter and lowest in spring in comparison with other seasons. The daily path length (DPL) varied from .75 to 5 km, with a mean of 2.1 km. Seasonal analysis showed that DPL is significantly shorter in winter than in spring or summer; however, there is no significant difference between the DPLs of spring and summer or those of spring and autumn. The monkeys occupied elevations 1500–2600 m above sea level; the annual mean of altitudinal range is 2137 m. Contrary to early studies that reported Rhinopithecus roxellana migrates to lower elevations in winter, we found no evidence supporting a seasonal altitudinal shift. Using the highest troop count and home range estimate, and considering the extent of range overlap between neighboring troops, we calculated the population density and biomass of Rhinopithecus roxellana to be 7.2 individuals/km2 and 68.3 kg/km2, respectively. The temporal and spatial distribution of food resources may be the most important determinant of ranging behavior in Rhinopithecus roxellana, though understanding the relationship between resource distribution and seasonal range use may require further investigation.  相似文献   

15.
Abstract: We captured and radiocollared 57 pronghorn (Antilocapra americana) fawns in western South Dakota, USA, during May 2002–2003 and radiotracked them through 15 months of age, by which time all surviving individuals had established a permanent home range. We classified 56% (n = 19) of fawns as dispersers and 44% (n = 15) as residents. Eighty-four percent (n = 16) of dispersers departed natal home ranges in late October and occupied winter home ranges for 102–209 days before dispersing to permanent home ranges during April 2003 and 2004. Dispersal distances from natal ranges to permanent home ranges varied from 6.2–267.0 km. Winter home-range sizes for all individual pronghorns varied from 39.4–509.6 km. Permanent home-range size for all individuals varied from 15.5–166.1 km2. Mean 95% permanent home-range size differed (P = 0.06) between residents (x̄ = 97.3 ± 15.1 km2) and dispersers (x̄ = 48.6 ± 16.0 km2), but was similar (P = 0.97) among sexes. Mean dispersal distance from natal to permanent home ranges was similar (P = 0.35) for males (x̄ = 54.2 ± 21.0 km) and females (x̄ = 26.3 ± 19.9 km). We suggest that habitat quality (i.e., patchiness) and pronghorn density, in part, stimulated dispersal. We hypothesize that as habitat patch size decreases, home range sizes and distance traveled during predispersal and dispersal movements by pronghorns will increase.  相似文献   

16.
Steven C. Minta 《Oecologia》1993,96(3):402-409
I tested the following hypotheses of territorial polygyny on badgers (Taxidea taxus: Carnivora; Mustelidae): Competition among adult females for food should result in intrasexual territoriality, while male competition for females should result in larger territories that encompass multiple female territories. The sagebrush-grassland study area (Wyoming, USA) contained a depauperate terrestrial fauna with a dense badger population preying on high densities of ground squirrels (Spermophilus armatus). Implant telemetry generated locations for analysis of home range and spatio-temporal interaction. During the summer breeding season males doubled movement rates and nearly tripled home range areas to overlap those of females. Before and after the breeding season, males reduced their home ranges to sizes nearer those of stable female ranges ( =2.82 km2). Unexpectedly, home range overlap between males and females was no different than intrasexual overlap. However, analysis of spatio-temporal interaction revealed that females spatially avoided one another, while males were spatially and temporally attacted to one another, similar to that of male-female interactions. Presumably, olfactory mechanisms allow resource tracking and lagged communication. Male-male territoriality was not viable, most likely because the high density of badgers, combined with the severely male-biased sex ratio (1.75:1), effectively increased intruder pressure — as a resource, receptive females were too mobile and spatially unpredictable within their home ranges. Consequently, males monitored and searched widely for relatively scarce females during the breeding season with the effect of attracting each other. Male mobility, home range size, and possibly aggression increased with age, suggesting age-related breeding tactics, although dominance could only be surmised. This and other studies suggest how the spatial, temporal, and dominance components of carnivore resource partitioning and sociality will be understood better by unraveling the interplay of olfactory processes, attributes of disparate resources (e.g., food vs. females), seasonality, and population density and age-sex structure.  相似文献   

17.
The macroscopic and microscopic diversity of potential food items available in the nests of plainfin midshipman Porichthys notatus were quantified and compared with items that were found in the stomach and intestine (digestive tract) of the guarding males. In this species, males occur as one of two possible reproductive morphs: guarder males that care for young and sneaker males that parasitize the courtship and care of guarder males. Although it was predicted that guarder males would have fewer feeding opportunities due to their confinement to the nest, they in fact had more food items in their digestive tracts than did sneaker males and females. Date in the breeding season (a proxy of care duration) and body condition were not correlated with the amount of food consumed by guarder males. The main type of food consumed was P. notatus embryos; 69% of all guarder males sampled had cannibalized offspring. By comparing the diet of both sexes and tactics, this study sheds light on some of the strategies designed to cope with the costs of providing parental care.  相似文献   

18.
Although female parasitic wasps are known to learn to associate odors with hosts and food, the ability of males to learn and detect odors has been neglected. We conducted laboratory experiments to compare the detection ability of learned odors between males and females in the larval parasitoid Microplitis croceipes (Cresson) (Hymenoptera: Braconidae). We first conditioned males and females to associate sucrose water with methyl benzoate, 3‐octanone, or cyclohexanone, and then observed their behavior toward various concentrations (40 ng l?1?4 mg l?1) of the trained odors. Conditioned male wasps responded as well as female wasps to various concentrations of the three odors. Response times by wasps to these three odors were not significantly different between sexes. For the three odors, response times of both sexes were longer at the intermediate concentrations (40–400 µg l?1) than the higher or lower concentrations. The present study suggests that M. croceipes males can learn and respond to the three chemicals tested as well as the females, and conditioned males are as sensitive to learned odors as conditioned females. By using their sensitive learning and odor‐detection capabilities, M. croceipes males could search for food sources as efficiently as females under natural conditions.  相似文献   

19.
Population dynamics, demography and home ranges of the Eurasian lynx Lynx lynx were studied in Bialowiez̊a Primeval Forest (BPF, 1250 km2), the best preserved mixed and deciduous forest in the lowlands of Europe; 40% of BPF area belongs to Poland and 60/0 to the Belarus Republic. Results of radiotelemetry of lynx (1991–1994) were combined with the Polish and Belarussian game departments' inventories of lynx numbers (1946–1994), archival hunting statistics (1869–1989), observations and snowtracking of lynx. In 1991–1994, 12 lynx were radiocollared. Their home ranges covered from SO to 246 km2 (mean 147 km2), depending largely on the time the lynx was radiotracked. During a given period, i.e. the autumn-winter seasons (I October-30 April), the home ranges were largest in adult males (90–148 km2), then in adult females (82–108 km2), and smallest in subadult lynxes (39–55 km2). Home ranges overlapped extensively. In winters 1992/93 and 1993/94, 21 and 29 lynxes, respectively, were recorded by the mapping of radiotracked and snowtracked individuals in the Polish part of BPF. Of them, 45/11 were ‘transborder’ individuals utilising both Polish and Belarussian pits of BPF. Winter densities were c. 3 adult lynx 100 km-2 and 5 lynx 100 km-2 if kittens were included. Adult males formed, on average, 29% and reproducing females 23% of all lynx. Subadults and kittens constituted, respectively, 12% and 35% of the population. Sex ratio was 1:1. During the first 3 months of kittens' life, on average 3.3 kittens/mother were recorded; only 1.6 young/mother survived till independence. Mortality of kittens was at least 48%, and the rate of mortality was highest during the early stage of kittens' life. Mean annual reproduction rate of lynx population was 0.59. In the protected population, annual mortality rate of subadult and adult lynx was on average 0.37. Poaching was the most important factor contributing 71% to the total annual mortality rate. During the last 125 years (1869–1994), three periods with relatively low harvest of lynx by man and thus with fairly natural functioning of lynx population, were recorded: before 1875 (density 2–3 lynx 100 km-2), in 1920–1959 (4–6 lynx 100 km-2) and after 1970 (2–5 lynx 100 km-2). The levels of lynx densities were most probably determined by the varying abundance of roe deer Capreolus capreolus and red deer Cervta elaphus (lynx's main prey) in the ungulate community in BPF. Two periods of near extermination of lynx occurred (1890–1914 and 1960–1970), both caused by deliberate persecution of lynx. As soon as persecution was abandoned, lynx population recovered rapidly, mainly due to immigration from vast continuous forests in the east and north-east. Review of the long-term data on lynx dynamics in the Palaearctic revealed that in the Far North-East (Yakutia), the 10-year cycles of lynx and the blue hare Lupus timidus, its main prey, were recorded. Towards west, the cycle period becomes shorter (5–6 years in the Komi region). In the SW regions of the Palaearctic, where lynx relies on ungulates, lynx numbers are more stable but, periodically, also more aflected by man.  相似文献   

20.
Sex differences in the quality and quantity of food loads brought to little auk (Alle alle) chicks were investigated in a large colony in Hornsund (South Spitsbergen). Adults returning to the colony were caught in mist-nets and food loads were taken from their gular pouch. The sex of each bird was determined by means of molecular methods. Females brought significantly more food per single load than males in terms of wet weight (30% more on average), number of prey items (46%) and energy contents (39%). However, there was no difference between the sexes in the size of prey taken. Energy-rich Calanus glacialis, originating from cold Arctic waters, was the most frequent prey item and made up the majority of food loads brought by both males and females (75 and 72%, respectively). This indicates that both sexes forage mainly in Arctic waters. However, differences in the proportion of cold water Calanus species (C. glacialis and C. hyperboreus), warm water Calanus species (C. finmarchicus), as well as other taxa, between males and females may suggest different ways of exploiting the feeding area.  相似文献   

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