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1.
Disturbance to wildlife from human recreational activities is increasing as remote areas become accessible to greater numbers of people. We used Global Positioning System tracking collars to monitor the movements of red deer (Cervus elaphus) stags (n = 8) in a herd whose feeding grounds lie close to a popular walking track in the Highlands of Scotland. The track is used by around 20,000 walkers per year and is busiest in summer and at weekends. In a 2-year study, the locations of collared deer were recorded at 2-h intervals on typically busy days (Sundays: mean number of walkers = 204) and quiet days (Wednesdays: mean number of walkers = 49) during May and June. The deer were consistently further from the track on Sundays than Wednesdays (371 vs 286 m) and moved greater distances between fixes (365 vs 308 m). The amount of time spent (percentage of total fixes) in the small area of grassland closest to the track was lower on Sundays than Wednesdays (6% vs 13%). Although 97% of walkers use the track during the day (between 0800 and 2000 h), there was no evidence of compensatory use of grassland at night, when the deer moved to higher ground dominated by heather moorland. The results demonstrate that animals which appear to be habituated to regular disturbance within their home territory may nevertheless alter their behaviour and potentially diet composition, as a result of that disturbance.  相似文献   

2.
Vigilance is a key to the early detection of predators, but may be costly if it impairs foraging efficiency. Hence, we would expect vigilance to be suppressed and/or counter‐selected in predator‐free environments, although this might depend on the environmental drivers influencing perceived predation risk. We studied vigilance in two populations of Sitka black‐tailed deer (Odocoileus hemionus sitkensis) on Haida Gwaii (Canada) which have not been exposed to predators since they colonized the study islands approx. 60 yr ago. In this context, anti‐predator behavior should not have any obvious current benefit. Moreover, its maintenance should be particularly costly in our study populations because these deer have depleted their food resources and, thus, anti‐predator behaviors should interfere with time spent searching for scarce resources. We used bait stations equipped with camera traps to assess vigilance under standardized feeding conditions. We expected to observe lower vigilance levels than those observed elsewhere in locations with predators. We investigated how vigilance varied in relation to the amount of bait, the level of visibility, and between day and night. During the day, deer spent, on average, 14% of their time in overt vigilance during foraging bouts, a level similar to, although in the lower range of, values reported at sites where predators are present. Levels of vigilance were lower at night, and decreased with increasing visibility, but not during the day. Deer were less vigilant when bait availability was high, but only when visibility was also high. We discuss why the maintenance of vigilance is here best explained by the ghosts of predators past, and how, at the temporal scale of a few generations, the ecological factors driving vigilance levels might override the absence of significant risk from large predators.  相似文献   

3.
The effect of various supplementary feeds on bark browsing was studied in red deer under controlled conditions. Fifteen female red deer were randomly assigned to five dietary treatments (n = 3 animals each): meadow hay as a control (C), combinations of meadow hay with grass silage (GS), maize silage (MS), maize silage with oats (MSO) or a pelleted concentrate (PC). The deer were kept in enclosures where we offered fresh spruce stems daily. The experiment consisted of two periods. In the first period (A), the animals had free access to food during 24 h, while in the second period (B), the access was restricted to night hours only. In both periods, the supplementary feeds were available ad libitum. Mean daily consumption of browsed bark in the control group in period A was 1,053 g while in the remaining groups it ranged from six to 20 g. In period B, simulating the conditions in disturbed hunting areas, bark consumption in all groups increased considerably, the highest increase being found in groups GS (430 vs. 19 g/day) and MS (101 vs. 6 g/day). In period A, the highest dry matter (DM) intake including browse was found in group MS (2,816 g/day) and the lowest one in group GS (2,307 g/day). In period B, the highest (2,763 g/day) and the lowest (2,153 g/day) DM intake was observed in groups PC and MSO, respectively. If red deer is fed supplementary, meadow hay should be combined with maize silage, grass silage or concentrate to reduce bark browsing in forests. The bark browsing rate may increase considerably if red deer are disturbed or their grazing cycle is impaired.  相似文献   

4.
An area of research that has recently gained more attention is to understand how species respond to environmental change such as the landscape structure and fragmentation. Movement is crucial to select habitats but the landscape structure influences the movement patterns of animals. Characterising the movement characteristics, utilisation distribution (UD) and habitat selection of a single species in different landscapes can provide important insights into species response to changes in the landscape. We investigate these three fields in female red deer (Cervus elaphus) in southern Sweden, in order to understand how landscape structure influences their movement and feeding patterns. Movements are compared between two regions, one dominated by a fragmented agriculture–forest mosaic and the other by managed homogenous forest. Red deer in the agriculture-dominated landscape had larger UDs compared to those in the forest-dominated area, moved larger distances between feeding and resting and left cover later in the day but used a similar duration for their movements, suggesting faster travelling speeds between resting and feeding locations. The habitat selection patterns of red deer indicate a trade-off between forage and cover, selecting for habitats that provide shelter during the day and forage by night. However, the level of trade-off, mediated through movement and space use patterns, is influenced by the landscape structure. Our approach provides further understanding of the link between individual animal space use and changing landscapes and can be applied to many species able to carry tracking devices.  相似文献   

5.
Resting site selection by European bison (Bison bonasus, L., 1758), the largest terrestrial mammal of Europe, was studied in the free-ranging population in Bia?owie?a Primeval Forest (Poland) in 2009–2010. In total, 104 sites of 21 bison (both collared and uncollared) were analysed to determine the most important microhabitat characteristics selected by resting bison during summer and winter and to study the influence of supplementary feeding on resting behaviour of this herbivore. Resting sites were identified on the basis of GPS locations and activity records collected by GPS collars, as well as direct observations of bison, and were compared with control sites. Microhabitat selection by bison did not differ significantly between the sexes. During summer and winter, bison resting sites displayed a high tree density, low visibility and high complexity (structures providing cover). Summer resting sites were also characterised by a significantly lower abundance of blood-sucking insects and denser canopy than control sites. Winter resting sites showed a lower complexity and higher visibility than summer sites, and were less often located in mixed forest habitats. During winter, bison rested more frequently in forest below 50 years of age than in older forest. Resting sites of non-fed bison were more often located in young coniferous forests, were lower in visibility and situated closer to open areas than sites of bison using supplementary winter feeding, suggesting a trade-off between food and cover. The results indicate that European bison select their resting sites in areas of mosaic habitat structure providing cover from disturbances with access to profitable natural forage grounds.  相似文献   

6.
Large boulder grazing refugia permitted comparison of saxicolous bryophyte and lichen assemblages with those boulder tops accessible to red deer (Cervus elaphus) on a sporting estate in northwest Scotland. Plant succession was predicted to occur unchecked by grazing on the tops of these large boulders with cascading effects on bryophytes and lichens—assuming boulders had been in place over the same time period. Fifty pairs of boulders (one ≥2 m and the other accessible to red deer) were selected at random from various locations below north-facing crags. Percentage cover of each bryophyte and lichen species was estimated from three randomly placed quadrats on each boulder top. Due consideration was given to the influence of island biogeography theory in subsequent model simplification. Mean shrub cover and height, leaf-litter, bryophyte cover and bryophyte species richness were significantly higher within quadrats on large boulder tops that naturally excluded red deer. Lichen cover and lichen species richness were significantly higher on boulder tops accessible to red deer. Lichen cover was in a significant negative relationship with bryophyte cover, shrub cover and litter cover. Bryophyte cover showed a significant positive relationship with shrub height but there was an optimum shrub cover. Natural exclusion of red deer from the tops of large boulders has facilitated plant succession. The results suggest that grazing arrests the lithosere on boulder tops accessible to red deer at an early plagioclimax favouring saxicolous lichens. The results are relevant to situations where red deer might be excluded from boulder fields that hold lichen assemblages of conservation value.  相似文献   

7.
Predator avoidance depends on prey being able to discern how risk varies in space and time, but this is made considerably more complicated if risk is simultaneously present from multiple predators. This is the situation for an increasing number of mammalian prey species, as large carnivores recover or are reintroduced in ecosystems on several continents. Roe deer Capreolus capreolus in southern Norway illustrate a case in which prey face two predators with contrasting patterns of predation risk. They face a catch‐22 situation: spatially avoiding the risk from one predator (lynx Lynx lynx in dense habitat) implies exposure to the other (hunters in open habitat). Using GPS‐data from 29 roe deer, we tested for daily and seasonal variation in roe deer selection for habitat with respect to the habitats’ year‐round average risk level. Generally, roe deer altered their habitat selection between night and day in a pattern consistent with being able to avoid predicted risk from the nocturnal lynx during night and predicted risk from human hunters during day. However, seasonal variation in habitat selection only partially corresponded with the predicted seasonal variation in risk. Whereas roe deer avoided areas with high risk from hunters more strongly during the hunting season than in other seasons, there was a lack of selection towards areas and time periods lowering the risk of lynx predation during winter. It seems likely that the risk of starvation and thermal stress constrain roe deer habitat selection during this energetically challenging season with cold temperatures, snow cover and limited natural forage. The habitat selection pattern of roe deer fits thus only partly with the two contrasting risk gradients they face. Adjusting risk‐avoidance behavior temporally can be an adaptive response in the case of several predators whose predation patterns differ in space and time.  相似文献   

8.
Diving and circadian behaviour patterns of 7 free-ranging Saimaa ringed sealsPhoca hispida saimensis Nordquist, 1899 were examined by VHF-radiotelemetry during open-water seasons between May and November in Lake Saimaa, eastern Finland. The mean recorded dive duration ranged from 2.8 to 6.5 min, with a maximum of 21 min. The mean dive depth ranged from 9.8 to 15.7 m, with maximum of 39.6 m. The maximum dive depth of each seal was limited by water depth in the study area. The dive depths were positively correlated with dive duration and body mass of the seal. Five different dive types were defined, as based on their depth-time characteristics, each falling into one of the three functional categories: travelling, feeding, and resting. Long duration diving bouts occurred mostly at night and were presumed to be resting dives. Saimaa ringed seals exhibited a circadian pattern of haul-out behaviour that shifted seasonally. During molting (May–June) the seals hauled-out both day and night, but later in summer haul-out was more frequent at night.  相似文献   

9.
In this study, we describe the process of pedicle and first antler growth in Iberian red deer (Cervus elaphus hispanicus) and document relationships among body development, maternal milk supply and composition, and maternal weight on the length of first antlers. Antler length of 53 males of Iberian red deer was measured every 2 weeks from birth to 20 months of age. Deer weight, age, and the date of occurrence of the major events during the antler growth cycle were also recorded. The first evidence of pedicle development occurred when the animals were 38.0 ± 0.6 weeks old and weighed 60.7 ± 0.9 kg. Antler cleaning took place at a mean age of 63.8 ± 0.7 weeks and a mean weight of 91.5 ± 1.8 kg. The antler growth period lasted 16.7 ± 0.4 weeks, and the cleaning period lasted 5.1 ± 0.4 weeks. First antler growth followed a sigmoid curve, reaching a final length of 38.3 ± 1.0 cm. Antler length was positively correlated with body weight during the antler growth cycle. Additionally, the final length of the first antler was related to total milk yield, date of antler growth initiation, body weight at 6 months of age, and the antler growth time interval.  相似文献   

10.
The selection of bedding sites is important for the ecology of ruminants, but has mainly been described for temperate species. Here we assessed the bed site selection of two Southeast Asian tropical deer, red muntjac and sambar, in Khao Yai National Park, Thailand. We surveyed transects weekly for 10 weeks each in 2003 and 2004 to locate bed sites, and compared the slope, aspect, and forest canopy cover of bed site locations between the two species and with available habitat. As with most temperate deer, muntjac and sambar both avoided sites with low levels of cover for their bed site locations; this could be for concealment or thermoregulation. Sambar also selected flatter sites than would be expected by the availability of topographic slopes; this could be to reduce the energy associated with getting to and from bed sites, or to increase long-range visibility from sites. Muntjac and sambar differed in their choice of aspects for bed sites; muntjac disproportionately chose west-facing areas, while sambar chose east-facing locations. This could represent a strategy by which one species avoids the other, or else differential resource requirements between the two species.  相似文献   

11.
Litter processing by macroinvertebrates typically involves suites of species that act together to determine rates of breakdown and decomposition. However, tropical oceanic islands and coastal fringes on continents are often dominated by one or a few species of omnivorous land crabs that consume leaf litter. We used an exclusion experiment, together with other leaf removal and litter decomposition studies, to assess the role of a single dominant species, the red crab (Gecarcoidea natalis), in litter dynamics in rain forest on Christmas Island, Indian Ocean. In the presence of red crabs, litter cover and biomass varied seasonally, from almost complete cover and high biomass at the end of the dry season to almost total absence of litter at the end of each wet season. When crabs were excluded from both the shaded understory and light gaps in rain forest, litter increased rapidly to almost complete cover, which was then maintained year round. Leaf tether experiments, and measures of litter input and standing crops, indicated that red crabs monopolize litter processing, removing between 39 and 87% of the annual leaf fall from the forest floor. Rates of litter turnover were over twice as high in the presence of land crabs: the decomposition constant, k, was 2.6 in the understory exclusion plots, but rose to 6.0 in the presence of crabs. Red crabs occur at biomass densities (114 g m−2) far greater than those reported elsewhere for entire litter faunas. They significantly reduced the abundance of other litter invertebrates, but we did not detect any change in the relative frequencies of the major invertebrate groups (mites, collembolans, pulmonate snails, ants, psocopterans, and spiders). Wherever omnivorous land crabs are abundant, their activities may be paramount in litter decomposition and in regulating the rate of nutrient cycling. In monopolizing litter processing, they may also be important physical “ecosystem engineers”, translocating organic matter and nutrients into the soil and reducing available habitat for other animals. Received: 19 August 1998 / Accepted: 11 January 1999  相似文献   

12.
Despite increased research during the past years, many characteristics of resting behavior in elephants are still unknown. For example, there is only limited data suggesting elephants express longer lying bouts and increased total nightly lying durations on soft substrates as compared to hard surfaces. Additionally, it has not been investigated how frequently elephants change body sides between lying bouts. Here we present these characteristics based on observations of nighttime lying behavior in 10 zoo elephants (5 African Loxodonta africana and 5 Asian Elephas maximus elephants) living in five different European facilities. We found that elephants housed on soft substrates have significantly increased total lying durations per night and longer average lying bouts. Furthermore, at 70%−85% of all bouts, a consistently higher frequency of side change between lying bouts occurred on soft substrates, leading to an overall equal laterality in resting behavior. Deviations from this pattern became evident in elephants living on nonsand flooring or/and in nondominant individuals of nonfamily groups, respectively. Based on our findings, we consider elephants to normally have several lying bouts per night with frequent side changes, given an appropriate substrate and healthy social environment. We encourage elephant-keeping facilities to monitor these characteristics in their elephants' nighttime behavior to determine opportunities for further improvements and detect alterations putatively indicating social or health problems in individual elephants at an early stage.  相似文献   

13.
The use of natural shelter in relation to weather by Red deer on open moorland is described. Most shelter-seeking behaviour in winter was associated with the chilling effects of wind. Although deer sheltered from both wind speed and temperature individually, the combined effect of these (i.e. "windchill") was likely to be most important. The most important individual factor was wind. In winter, resting deer sheltered from the wind by lying on lee slopes, in long vegetation, on dry ground and in places with small amounts of geomorphic shelter; they sought very sheltered places only during blizzards. Deer were found in more shelter as windchill increased, and did not appear to seek constant conditions from day to day. They put up with worse conditions when feeding than when resting. On summer days with high temperatures and strong sun, deer were seen standing when at rest, and were found in the shade, and on wet or bare ground; they also lay in the wind, bathed in water or stood on patches of old snow.  相似文献   

14.
Activity patterns in moose and roe deer in a north boreal forest   总被引:5,自引:0,他引:5  
The activity patterns of a coarse browser, the moose. Alces alces , and a selective browser, the roe deer, Capreolus capreolus . in a north boreal forest, central Sweden, were compared with respect to time allocated for foraging and processing (ruminating) in different seasons. Data were quantified by measuring 24 h activity patterns which included both the duration and frequency of active and inactive periods. Activity patterns were measured from 9 female moose and 9 roe deer that were radiomarked during April 1974–May 1978 (roe deer) and February 1982–December 1984 (moose). In total, data were available from 4345 h for roe deer and 14745 h for moose. Roe deer differed from moose in having active bouts more evenly distributed over the day. Generally, both species were most active during sunrise and sunset. Total daily active time varied with season, reaching the highest value in late May – early June among roe deer (56.7% of the day) and a month later among moose (51.9%). Both species were least active in February (30–40%). Average length of active bouts did not differ significantly between the species but changed with season (roe deer 48.6–99.2 min, moose 61.6–88.7 min). Average length of inactive bouts varied significantly with season, with moose having consistently longer bouts (89.3–156.3 min) than roe deer (55.8–107.0 min). The number of activity bouts per day were also higher among roe deer. During midsummer, they changed activity nearly twice as many times as moose (26 times d−1 vs 16 times d−1).  相似文献   

15.
1. Activity patterns of Aphytis lingnanensis Compere (Hymenoptera: Aphelinidae) females were determined. Females have a preovipositional period of 2–6.5 h and oviposit daily until they die. The average lifetime fecundity was 191 eggs (n = 10 females), with a maximum of 13 eggs per day, but usually far fewer. Females do not lay eggs at night as low light levels reduce the propensity to oviposit. 2. Aphytis lingnanensis females showed a repeatable pattern of activity during the course of the day, ovipositing actively during the first 1.5 h of their 7 h exposure to hosts. Thereafter, activity levels decreased sharply and females spent relatively long intervals resting. Activity occurred in fairly discrete bouts, with long periods of inactivity, ranging from 12 to 231 min between bouts. 3. Each day, females laid most eggs during their first bout of oviposition, with availability of mature eggs in the ovaries dictating the duration and intensity of ovipositional bouts. Once females completed a bout of oviposition in the laboratory, they moved away from the hosts even though many suitable hosts remained. They stood immobile, sheltering, until they matured more eggs. 4. These results suggest how general biological control models and dynamic state variable models of behaviour can be made more realistic. In particular, the behaviour of females does not remain constant over extended periods, particularly because of egg depletion, which suggests that the interaction between the ovipositional history of the individual and its physiological capabilities dictates the response of females to particular circumstances, and thus contributes to patterns of parasitism in the field. 5. It is predicted that A. lingnanensis females in the field are inactive at night and begin ovipositing when it becomes light enough in the morning. Egg depletion is likely if enough hosts are available, but should occur later in the day than was recorded in the laboratory. Egg-depleted females are likely to shelter while they mature more eggs, but may undertake interpatch movement.  相似文献   

16.
The aim of this study was to determine concentrations of selenium in the liver and kidneys of roe deer and red deer from West Pomerania, depending on the season. Altogether, samples from 169 animals were collected (96 from roe deer and 73 from red deer) in 2003–2007. The mean concentration of selenium in the liver of red deer and roe deer was 0.37 μg/g and 0.62 μg/g dry weight, respectively. In kidneys, Se concentration was 2.72 μg/g d.w. in red deer and 2.99 μg/g d.w. in roe deer. In roe deer, liver selenium concentration in autumn was significantly higher than in winter (P < 0.05) and spring (P < 0.01) and significantly lower in spring than in summer (P < 0.05); likewise, kidney selenium concentration was higher in autumn than in summer. In deer, no statistically significant season-related differences were observed for liver selenium concentrations. In red deer kidneys, selenium concentration was the lowest in summer, significantly lower than in autumn and winter. Low selenium concentrations in the analyzed tissues show that the animals live in areas deficient in this element.  相似文献   

17.
Body temperature (T b) of seven European hamsters maintained at constant ambient temperature (T a = 8 °C) and constant photoperiod (LD 8:16) was recorded throughout the hibernating season using intraperitoneal temperature-sensitive HF transmitters. The animals spent about 30% of the hibernation season in hypothermia and 70% in inter-bout normothermy. Three types of hypothermia, namely deep hibernation bouts (DHBs), short hibernation bouts (SHBs), and short and shallow hibernation bouts (SSHBs), were distinguished by differences in bout duration and minimal body temperature (T m). A gradual development of SSHBs from the diel minimum of T b during normothermy could be seen in individual hamsters, suggesting a stepwise decrease of the homeostatic setpoint of T b regulation during the early hibernation season. Entry into hibernation followed a 24-h rhythm occurring at preferred times of the day in all three types of hypothermia. DHBs and SHBs were initiated approximately 4 h before SSHBs, indicating a general difference in the physiological initiation of SSHBs on the one hand and DHBs and SHBs on the other. Arousals from SHBs and SSHBs also followed a 24-h rhythm, whereas spontaneous arousals from DHBs were widely scattered across day and night. Statistical analyses of bout length and the interval between arousals revealed evidence for a free-running circadian rhythm underlying the timing of arousals. The results clearly demonstrate that entries into hypothermia are linked to the light/dark-cycle. However, the role of the circadian system in the timing of arousals from DHBs remains unclear. Accepted: 11 December 1996  相似文献   

18.
1. Full sunlight conditions in open clear‐cuts may limit the activity of ants as soil surface temperatures reach lethal levels. Therefore, differences may be expected between the diurnal and nocturnal activity of ants, and in the interactions between ant species. These predictions, however, have been poorly investigated so far. 2. The circadian activity of ants in clear‐cuts in managed forests in Poland was investigated. Repeated counts of ants were performed during the day and the following night at the clear‐cut edge and in the clear‐cut interior. Interspecific interactions and the effect of plant coverage were also considered. 3. Abundances of Formica fusca Linnaeus and red wood ants were higher during the day, whereas Myrmica were more common at night. Formica fusca, Lasius and red wood ants were more common at the clear‐cut edge than in the interior. Myrmica showed the opposite pattern, but at night, its numbers increased at the edge. Plant coverage positively affected F. fusca and red wood ants. 4. Red wood ants tended to be negatively associated with Lasius, whereas they were neutral for F. fusca. The negative association of red wood ants and Myrmica was stronger during the day compared to night. 5. The time of day was a strong driver of ant activity in the clear‐cuts, whereas the distribution of red wood ants was of lesser importance. It is concluded that circadian activity may substantially contribute to niche separation between coexisting species, therefore, studies performed exclusively during the day cannot reflect the real structure of the community.  相似文献   

19.
2009年12月~2010年1月,在黄泥河自然保护区采用样带法对马鹿冬季栖息地选择进行了研究。共设置了47条样带,调查了72个马鹿利用样方和109个对照样方。结果表明,在黄泥河自然保护区冬季马鹿喜欢选择针阔混交林、食物丰富度和灌丛盖度较高、中等坡度和隐蔽级、远离人为干扰源的生境,避开选择阴坡和针叶林。逻辑斯蒂回归分析揭示坡度、隐蔽级、食物丰富度、坡向、人为干扰距离和林型是影响马鹿栖息地选择的主导因子,灌丛盖度为次要因子。回归模型为:Z=-53.391+0.194×坡度+0.352×隐蔽级+0.5×食物丰富度-0.071×灌丛盖度+1.064×坡向(1)+6.11×坡向(2)+0.004×人为干扰距离+17.305×林型(1)+7.147×林型(2),选择利用概率P(z)=ez/(1+ez),模型正确预测率为94.5%。  相似文献   

20.
European fallow deer are an introduced species classified as partly protected wildlife in Tasmania, Australia. Current management practices are primarily governed under the Quality Deer Management regime, in which animals are harvested during designated hunting seasons. Among populations, prominent morphological differences have been reported; however, the genetic relationship of these populations has until now been poorly understood. Representative animals were sampled from three key areas across their range and genotyped at ten polymorphic microsatellite loci to investigate genetic diversity, population structure, and genetic bottlenecks. Allelic richness was low in all three populations and ranged between 2.20 and 2.49 alleles/locus. A genetic bottleneck was detected in two of the three populations (P < 0.001). Population differentiation was evident between Lake Echo and Benham (q = 0.122; P < 0.001) and Benham and Connorville (q = 0.110; P < 0.001), but not between Lake Echo and Connorville (q = 0.0235), with individuals being identified as belonging to two genetic clusters. The pattern of population differentiation from the three study populations suggests that deer from the western region of their range are genetically distinct to those from the eastern region. This correlates with morphological variation within Tasmanian fallow deer, in which differences between the regions maybe attributable to geographical barriers.  相似文献   

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