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1.
Factors affecting territory size in wolves Canis lupus were studied at 2 scales, the local population (Bia?owie?a Primeval Forest (BPF), eastern Poland) and the geographic range of species (literature review from 14 localities in the Holarctic). Four packs of wolves were studied by radio‐tracking in BPF from 1994 to 1999. The annual territories of packs (Minimum convex polygons with 95% of locations) averaged 201 km2 (SD 63, range 116–310). Core areas of territories (50% MCP) covered from 14 to 78 km2 (mean 35). Territory sizes and core areas both were negatively correlated to the encounter rates of ungulates (mean number of ungulates seen per unit time spent in the forest by human observers). Pack size (3–8 wolves) did not influence territory size. Home ranges of individual wolves from the same pack varied with season as well as the age, sex, and reproductive status of the wolf. Review of literature from North America and Europe (42–66oN), showed that latitude and prey biomass were essential factors shaping the biogeographic variation in wolf territory size. Territories increased with latitude and declined with growing biomass of prey. The analysis showed that latitude acted partly independently of the south–north gradient in prey abundance. At similar standing crop of ungulate biomass (100 kg km?2), wolf territories would average 140 km2 at 40oN, 370 km2 at 50oN, and 950 km2 at 60oN. Pack size was larger at northern latitudes, but the increase did not keep pace with enlargement of territories. Within‐territory density of wolves declined from 2.5–3 wolves 100 km?2 at 40–45oN to 0.7 wolves 100 km?2 at 60oN. Our analyses documented similarities regarding the role of prey resources in shaping wolf territoriality at the different scales. Furthermore, a macroecological approach revealed additional factors affecting wolf territory size that were not emergent from knowledge of local population.  相似文献   

2.
ABSTRACT During summer 2005, we evaluated space and habitat use by red wolves (Canis rufus) during pup-rearing. Home-range sizes for red wolves (3 ad, 3 juv, and 4 pups) varied from 3.48 km2 to 12.24 km2. Red wolves selected agricultural fields over adjacent forested areas and used less space during pup-rearing than we expected based on prior knowledge of the species. Attending pack members rarely left pups alone, pack members shared pup-rearing duties, and male red wolves appeared to play a significant role in pup-rearing.  相似文献   

3.
Understanding the nature of the interactions between humans and wildlife is of vital importance for conflict mitigation. We equipped five leopards with GPS-collars in Maharashtra (4) and Himachal Pradesh (1), India, to study movement patterns in human-dominated landscapes outside protected areas. An adult male and an adult female were both translocated 52 km, and exhibited extensive, and directional, post release movements (straight line movements: male  = 89 km in 37 days, female  = 45 km in 5 months), until they settled in home ranges of 42 km2 (male) and 65 km2 (female). The three other leopards, two adult females and a young male were released close to their capture sites and used small home ranges of 8 km2 (male), 11 km2 and 15 km2 (females). Movement patterns were markedly nocturnal, with hourly step lengths averaging 339±9.5 m (SE) during night and 60±4.1 m during day, and night locations were significantly closer to human settlements than day locations. However, more nocturnal movements were observed among those three living in the areas with high human population densities. These visited houses regularly at nighttime (20% of locations <25 m from houses), but rarely during day (<1%). One leopard living in a sparsely populated area avoided human settlements both day and night. The small home ranges of the leopards indicate that anthropogenic food resources may be plentiful although wild prey is absent. The study provides clear insights into the ability of leopards to live and move in landscapes that are extremely modified by human activity.  相似文献   

4.
Free-ranging gray wolves (Canis lupus) generally inhabit large home ranges, yet they are housed in a variety of restricted spaces when in captivity. There is continual debate as to whether space restrictions alter a wolf's behavior. The purpose of these studies was to remotely measure and then compare the amount and frequency of activity of gray wolves housed in small, artificial enclosures vs. large, more natural enclosures. Test animals comprised three adult wolves housed in kennels and three and four wolves housed in separate natural enclosures. Kenneled wolves had 2.8 m2 of surface area per wolf, and wolves in natural enclosures had 466.6 m2 (South Pack) and 349.9 m2 (North Pack) per wolf. Wolves were fitted with radiotelemetry collars containing activity sensors. Activity data were recorded every 20 min for 57 continuous hr. The amount of activity for each wolf was calculated using areas under the curve (AUCs), and the frequency of activity was analyzed by spectral analysis. There was no difference (P ≥ 0.22) in AUCs between kenneled wolves (1.399 ± 0.214 x 105 radians) and South Pack wolves (1.564 ± 0.139 X 105 radians) or North Pack wolves (1.617 ± 0.192 x 105 radians). All three groups had similar peak spectral values at frequencies that were close to daily cycles (i.e., ω = 0.12–0.17 cycles per unit time). Peaks in coherence near the dominant spectral frequency were most significant between the natural enclosures and the least significant between the kenneled wolves and the South Pack wolves. Based on these criteria of activity and under these circumstances, enclosure size appeared to have no effect on wolf activity. However, small sample sizes and variation in the data do not make these results definitive. © 1996 Wiley-Liss, Inc.  相似文献   

5.
Abstract As wolves (Canis lupus) recover in Poland, their depredation on domestic animals is increasing, as have conflicts between wolves and farmers. From 1998 to 2004, I investigated spatial and temporal patterns of 591 verified incidents of wolf depredation in the eastern part of the Polish Carpathian Mountains. The wolf population I surveyed covered an estimated range of 4,993 km2. Depredation occurred over 1,595 km2 of that area. Sheep accounted for 84.8% of domestic animals killed by wolves. Depredation on sheep and number of sheep farms attacked by wolves increased between 1998 and 2004 (r2 = 0.61, P = 0.04 and r2 = 0.89, P = 0.02, respectively). The number of wolf attacks on sheep farms in a given year were negatively correlated to red deer (Cervus elaphus) population numbers (R2 = 0.69, P = 0.02). The amount of depredation caused by each of the 4 monitored packs was best explained by farm density in their territories (R2 = 0.59, P = 0.004). Number of attacks recorded on farms was positively correlated to distance from the farm to the pack's den and rendezvous sites (R2 = 0.16, P = 0.04). Of depredation recorded in the 4 pack's territories I surveyed, 77% occurred in 4 farms with no or inadequate protection. I concluded that wolf depredation in the studied area is opportunistic. Wolf predation intensity is a function of decreasing abundance of red deer, the density of sheep farms, and proximity of farms to the summer activity centers of wolf packs, and it is facilitated by poor husbandry practices. These results can aid in preventing wolf depredation and provide a foundation for a wolf management plan.  相似文献   

6.
Predation is the dominant source of mortality for white-tailed deer (Odocoileus virginianus) <6 months old throughout North America. Yet, few white-tailed deer fawn survival studies have occurred in areas with 4 predator species or have considered concurrent densities of deer and predator species. We monitored survival and cause-specific mortality from birth to 6 months for 100 neonatal fawns during 2013–2015 in the Upper Peninsula of Michigan, USA, while simultaneously estimating population densities of deer, American black bear (Ursus americanus), coyote (Canis latrans), bobcat (Lynx rufus), and gray wolf (Canis lupus). We estimated fawn predation risk in response to sex, birth mass, and date of birth. Six-month fawn survival pooled among years was 36%, and fawn mortality risk was not related to birth mass, date of birth, or sex. Estimated mean annual deer and predator densities were 334 fawns/100 km2, 25.9 black bear/100 km2, 23.8 coyotes/100 km2, 3.8 bobcat/100 km2, and 2.8 wolves/100 km2. Despite lower estimated per-individual kill rates, coyotes and black bears were the leading sources of fawn mortality because they had greater densities relative to bobcats and wolves. Our results indicate that the presence of more predator species in a system is not entirely additive in its effect on fawn survival. © The Wildlife Society, 2019  相似文献   

7.
Synopsis Radio telemetry was used to study the movements of European eels,Anguilla anguilla, in a small (1.2 ha) lake in southwestern Spain in March and April, 1985. Observations were taken on the locations of 7 eels at least once each 2 h for a combined total of 1713 h. The size of individual activity regions varied from 2700 to 1300 m2. Eels covered a larger area at night than during the day, with an average of 23% and 42% of the activity region used during the day and night respectively. Average distance moved between observations was significantly greater at night than in the day. Eels tracked during rainy and cloudy weather were more active during the day and used a larger total area than did those tracked during drier, more stable weather. The standing crop of eels was estimated to be about 77 kg ha–1.  相似文献   

8.

Background

Predation and hunter harvest constitute the main mortality factors affecting the size and dynamics of many exploited populations. The re-colonization by wolves (Canis lupus) of the Scandinavian Peninsula may therefore substantially reduce hunter harvest of moose (Alces alces), the main prey of wolves.

Methodology/Principal findings

We examined possible effects of wolf presence on hunter harvest in areas where we had data before and after wolf establishment (n = 25), and in additional areas that had been continuously exposed to wolf predation during at least ten years (n = 43). There was a general reduction in the total number of moose harvested (n = 31,827) during the ten year study period in all areas irrespective of presence of wolves or not. However, the reduction in hunter harvest was stronger within wolf territories compared to control areas without wolves. The reduction in harvest was larger in small (500-800 km2) compared to large (1,200-1,800 km2) wolf territories. In areas with newly established wolf territories moose management appeared to be adaptive with regard to both managers (hunting quotas) and to hunters (actual harvest). In these areas an instant reduction in moose harvest over-compensated the estimated number of moose killed annually by wolves and the composition of the hunted animals changed towards a lower proportion of adult females.

Conclusions/Significance

We show that the re-colonization of wolves may result in an almost instant functional response by another large predator—humans—that reduced the potential for a direct numerical effect on the density of wolves’ main prey, the moose. Because most of the worlds’ habitat that will be available for future colonization by large predators are likely to be strongly influenced by humans, human behavioural responses may constitute a key trait that govern the impact of large predators on their prey.  相似文献   

9.
The distribution and abundance of spotted seals (Phoca largha) and ribbon seals (Phoca fasciata) were assessed in March and April, 2000, by aerial line-transect surveys along the southern edge of the pack ice off the coast of Hokkaido (southern Sea of Okhotsk), Japan. Five hundred and seventeen spotted seals and 107 ribbon seals were found on the total 2944 km survey line. Total abundance was estimated to be 13 653 spotted (95% CI = 6167–30 252) and 2260 ribbon seals (95% CI = 783–6607) in March, and 6545 spotted (95% CI = 3284–815 644) and 3134 ribbon seals (95% CI = 1247–17 802 512) in April. The pack ice area off Hokkaido had higher densities (0.54 seals km–2 and 0.58 seals km–2 in March and April, respectively) of spotted seals than those reported in eastern Sakhalin, whereas densities (0.09 seals km–2 in March and 0.28 seals km–2 in April) of ribbon seals were lower than those in eastern Sakhalin. The large number of spotted seal pups suggests that the study area is an important breeding center. A greater number of female spotted seals with pups tended to be found in the center of larger and rougher floes than in other categories, and they were more abundant in stable pack ice areas. Observations of ribbon seals were limited because the survey period preceded the peak of pupping season. Ribbon seal surveys were also hampered by the inability to fly over the main breeding area between the Shiretoko Peninsula and Kunashiri Island.  相似文献   

10.
The most widely reported threat to boreal and mountain populations of woodland caribou (Rangifer tarandus caribou; caribou) involves habitat- or disturbance-mediated apparent competition (DMAC). With DMAC, natural and anthropogenic disturbances that increase the abundance of deciduous-browsing cervids (e.g., moose [Alces alces], deer [Odocoileus spp.]) are thought to promote predator (especially wolf [Canis lupus]) numbers, which heightens predation risk to caribou. We know most about the effects of DMAC on caribou where the species is under threat by anthropogenic activities in relatively productive southern boreal and mountain systems. Yet, >60% of extant boreal caribou range in North America consists of northern shield and taiga ecoregions of low productivity where caribou may compete with only 1 ungulate species (moose) in the context of DMAC. In this environment, we know very little of how DMAC acts as a limiting factor to caribou. In Saskatchewan, Canada, from 2014–2018, using a combination of vegetation sampling, aerial surveys, and telemetry data (n = 38 wolves), we searched for evidence of DMAC (trends in data consistent with the hypothesis) in an 87,193-km2 section of the Western Boreal Shield, a poorly productive but pristine region (0.18% of land cover classed as an anthropogenic feature) with a historically high fire-return interval (47% of stands aged <40 years). Despite the high levels of disturbance, moose density was relatively low (47 moose/1,000 km2), likely because of the scarcity of deciduous or mixed-wood stands and low abundance of deciduous browse in the young conifer stands that dominated the landscape. In contrast, boreal caribou density was relatively high for the species (37 caribou/1,000 km2). Wolf density (3.1 wolves/1,000 km2) and pack sizes ( = 4.0 wolves/pack) were low and resident (established) territories were large ( = 4,360 km2; 100% minimum convex polygon). The low density of wolves mirrored the low (standardized) ungulate biomass index (UBI; moose + boreal caribou) of the study area (0.36 UBI/km2). We conclude that wolf and hence caribou populations were not responding in accordance with the outcomes generally predicted by DMAC in our study area because the requisite strong, positive response to fire of deciduous-browse and alternate-prey abundance was lacking. As a limiting factor to caribou, DMAC is likely modulated at a macroecological scale by factors such as net primary productivity, a corollary to the general hypothesis that we advance here (i.e., primary productivity hypothesis of DMAC). We caution against managing for caribou based on the presumption of DMAC where the mechanism does not apply, which may include much of boreal caribou range in the north. © 2020 The Wildlife Society.  相似文献   

11.
Aim We reviewed 54 studies reporting population densities of wild boar (Sus scrofa) in western Eurasia in order to investigate the roles of vegetation productivity [fraction of photosynthetically active radiation (FPAR) index], winter harshness (mean January temperature) and presence/absence of wolves (Canis lupus) in shaping the biogeographical variation in population density of wild boar. Location We collected published data on the autumn–winter population density of wild boar (number of individuals km?2) in 54 locations in western Eurasia, from 1966 to 2003. Methods The mean January temperature, obtained from the World Climate data base ( http://www.worldclimate.com ), was taken as a measure of winter severity. We used monthly 4 × 4 km MODIS FPAR data sets covering January 2000 to June 2004 to calculate the vegetation productivity index. In addition, we collected literature data about the presence or absence of wolves from the study areas. Results In the geographical span of 37–60° N, the population densities of wild boar declined by three orders of magnitude, from 10 to 0.01 individuals km?2. The best multiple regression model (selected with the Akaike information criterion corrected for small samples) showed that mean January temperature and the vegetation productivity index were the most important factors explaining the biogeographical variation in population densities of wild boar. The impact of temperature was stronger than that of productivity. The presence of wolves had a weak limiting effect on population densities of wild boar at the biogeographical scale. Main conclusion We propose that winter harshness imposes density‐independent mortality on wild boar populations at higher latitudes. Competition for food in less productive regions may cause stronger density dependence in birth and death rates of wild boar populations. We expect that wild boar will respond to global warming by both an increase in local population densities and an expansion of their geographical range north and north‐eastwards.  相似文献   

12.
We studied the influence of agricultural villages on space-use patterns of golden jackals (Canis aureus Linnaeus) in the Mediterranean region of Israel. Villages in our research area attract jackals due to poor sanitation conditions in and around villages. As resources in these villages are abundant and predictable, we expected that space-use patterns of jackals near those villages, including home-range characteristics and movement paths, would differ from those of jackals inhabiting more natural areas. Using radio-locations from 16 individuals (8 near villages and 8 from more natural areas), we found that mean home-range size of jackals close to villages was 6.6 ± 4.5 km2, smaller than mean home-range size of jackals in more natural areas (21.2 ± 9.3 km2, P = 0.001). Similarly, core area size of jackals near villages was 1.2 ± 0.92 km2, compared to 3.5 ± 1.6 km2 for individuals inhabiting more natural areas (P = 0.004). The core area/home-range ratio was greater for jackals near villages than for those occupying more natural areas (0.122 ± 0.045 vs. 0.095 ± 0.037, respectively, P = 0.004). Jackals moved little during the day, with day ranges smaller for jackals near villages than away from them (1.65 ± 0.67 vs. 7.5 ± 5.6 km2, respectively, P = 0.028). However, jackals near villages moved as much at night as did jackals in more natural areas, although movement was in a less directional manner. Changes in distribution and predictability of resources due to anthropogenic activity affect not only the home-range size of jackals, but also how they utilize and move through space. © 2011 The Wildlife Society.  相似文献   

13.
With extinction rates far exceeding the natural background rate, reliable monitoring of wildlife populations has become crucial for adaptive management and conservation. Robust monitoring is often labor intensive with high economic costs, particularly in the case of those species that are subject to illegal poaching, such as elephants, which require frequent and accurate population estimates over large spatial scales. Dung counting methods are commonly employed to estimate the density of elephants; however, in the absence of a full survey calibration, these can be unreliable in heterogeneous habitats where dung decay rates may be highly variable. We explored whether motion-sensitive cameras offer a simple, lower cost, and reliable alternative for monitoring in challenging forest environments. We estimated the density of African savanna elephants (Loxodanta africana) in a montane forest using the random encounter model and assessed the importance of surveying parameters for future survey design. We deployed motion-sensitive cameras in 65 locations in the Aberdare Conservation Area in Kenya during June to August in 2015 to 2017, for a survey effort of 967 days, and a mean encounter rate of 0.09 ± 0.29 (SD) images/day. Elephants were captured in 16 locations. Density estimates varied between vegetation types, with estimates ranging from 6.27/km2 in shrub, 1.1/km2 in forest, 0.53/km2 in bamboo (Yushania alpine), and 0.44/km2 in the moorlands. The average speed of animal movement and the camera detection zone had the strongest linear associations with density estimates (R = −0.97). The random encounter model has the potential to offer an alternative, or complementary method within the active management framework for monitoring elephant populations in forests at a relatively low cost.  相似文献   

14.
Thysanoessa macrura was found throughout Gerlache Strait, Antarctica, during four surveys carried out from 30 October to 23 November 1989, with the highest abundance being 332 individuals m–2 (0–290 m). Reproduction had begun just before the surveys took place, as indicated by the presence of females with attached spermatophores and of larvae. Thirteen-month old females were reproductive. Larvae in 9 depth strata between 0–290 m were dominated by calyptopis stages, and developed from calyptopis 1 to furcilia 1 during November. Larval abundance was not correlated to chlorophyll a concentration, which showed a consistent east-west gradient in Gerlache Strait with highest concentrations (>30 mg chlorophyll a m–3) in bays of the Antarctic Peninsula. Survival of larvae appeared to not be affected by phytoplankton abundance. Older T. macrura showed strong diel vertical migration between the surface at night and depths to 120 m during mid-day. Larvae were consistently found in the chlorophyll a-rich upper 50 m during night (90%) and day (81%), while adults and juveniles were found in the upper 50m at night (83%), but only 16% remained there during the day.  相似文献   

15.
Human-caused habitat change has been implicated in current woodland caribou (Rangifer tarandus caribou) population declines across North America. Increased early seral habitat associated with industrial footprint can result in an increase in ungulate densities and subsequently those of their predator, wolves (Canis lupus). Higher wolf densities can result in increased encounters between wolves and caribou and consequently higher caribou mortality. We contrasted changes in moose (Alces alces) and deer (Odocoileus spp.) densities and assessed their effects on wolf–caribou dynamics in northeastern Alberta, Canada, pre (1994–1997) versus post (2005–2009) major industrial expansion in the region. Observable white-tailed deer (O. virginianus) increased 17.5-fold but moose remained unchanged. Wolf numbers also increased from approximately 6–11.5/1,000 km2. Coincident with these changes, spatial overlap between wolf pack territories and caribou range was high relative to the mid-1990s. The high number of wolf locations in caribou range suggests that forays were not merely exploratory, but rather represented hunting forays and denning locations. Scat analysis indicated that wolf consumption of moose declined substantively during this time period, whereas use of deer increased markedly and deer replaced moose as the primary prey of wolves. Caribou increased 10-fold in the diet of wolves and caribou population trends in the region changed from stable to declining. Wolf use of beaver (Castor canadensis) increased since the mid-1990s. We suggest that recent declines in woodland caribou populations in the southerly extent of their range have occurred because high deer densities resulted in a numeric response by wolves and consequently higher incidental predation on caribou. Our results indicate that management actions to conserve caribou must now include deer in primary prey and wolf reduction programs. © 2010 The Wildlife Society  相似文献   

16.
Walked spotlight transect surveys with distance sampling were used to estimate regional population densities of badger (Meles meles), fox (Vulpes vulpes) and brown hare (Lepus europaeus) in south-west England (Cornwall, Devon, Gloucestershire, Herefordshire) and Wales (Pembrokeshire, Borders, North Wales). All regions were surveyed during spring 2006 with English regions re-surveyed in autumn 2006. In each region, surveys were conducted in a random sample of 19.6 km2 areas (mean areas per region: spring = 19, autumn = 25). Within each survey area, a semi-random transect was established in each of a random sample of fields (open habitat almost exclusively pasture). Transects were subsequently walked at night with spotlights (mean transects per survey area: spring = 21, autumn = 21). Each area was surveyed twice during a season. Total transect length per region ranged from 137 to 193 km in spring and 230 to 250 km in autumn. The mean density of species per region was: badger 1.5–4.8 km−2, fox 1.0–4.0 km−2, hare 0.4–4.6 km−2. The study has provided baseline estimates of regional densities against which any future equivalent surveys can be compared. It has also illustrated the practical application of large-scale walked distance sampling to surveys of British mammals.  相似文献   

17.
Acoustic tags and receivers were used to investigate the spatial ecology of coastal Atlantic cod Gadus morhua (n = 32, mean fork length: 50 cm, range: 33–80 cm) on the Norwegian Skagerrak coast in 2012. Monthly home ranges (HR), swimming activity and depth use varied considerably among individuals and through the months of June, July and August. HR sizes for the period ranged from 0·25 to 5·20 km2 (mean = 2·30 km2). Two thirds of the tagged G. morhua were infected with black spot disease Cryptocotyle lingua parasites; these fish had larger HRs and occupied deeper water compared with non‐infected fish. The infected fish also tended to be more active in terms of horizontal swimming. From an ecological and evolutionary perspective, any environmental change that modifies G. morhua behaviour may therefore also alter the parasite load of the population, and its conservation and fishery status.  相似文献   

18.
Griffon vulture (Gyps fulvus) population surveys were conducted during 1996–2002 in the island of Crete (Greece) to document population status and structure. Fieldwork was carried out during the breeding period when birds could be monitored in their colonies. Total population size was estimated at 379 individuals (range = 341–417) with adult birds comprising 63%. The breeding population was estimated at 141 pairs, which were distributed on an average in 23 colonies per year (range = 16–30) while the mean number of breeding pairs that laid eggs was 98 (range= 64–126). Crete thus supports the largest insular population of the species in the world and hosts 70–80% of the breeding population of the species in Greece. Population density was estimated at 6.9 individuals/100 km2, 2.6 breeding pairs/100 km2 and 1.8 nesting pairs/100 km2. The average home range of an occupied colony (i.e., breeding group) was estimated at ca. 204 km2 producing a theoretical foraging range of 8 km radius around the breeding cliff. No trends in the total number of individuals and breeding pairs appeared to exist, although significant differences in population size of individual colonies occurred between the years. The majority of the population was concentrated in small-sized colonies, which showed a low occupancy rate. The number of abandoned sites and the colonization of new ones could represent a shift of breeding pairs to alternative colonies provoked by local food abundance and conspesific attraction.  相似文献   

19.
The social organization of Asiatic lions (Panthera leo persica) differs from African lions (P. l. leo) in that breeding lionesses defend resource based territories while male coalitions maximize coverage of female groups. Thus, lion density in the Gir forests of India is dictated by female territory size. We studied the home range and habitat preference of lions using radio telemetry on seven lionesses spaced throughout the Gir between 2002 and 2005. Radio locations obtained by homing in were plotted on a classified (LISS III FCC) habitat map of Gir to obtain habitat use and availability. Habitat preference was computed using compositional analysis and Ivlev’s index. Average (±SE) 100% Minimum Convex Polygon (MCP) range of six lionesses was 48.2 ± 10.6 km2, 95% MCP was 34.7 ± 7.8 km2 and 95% fixed kernel range size was 32.5 ± 8.2 km2. Breeding female group density and group size was about 3 per 100 km2 and 1.3 (0.5 SD, n = 45) respectively. Lions were observed to show a habitat preference (c(6df)2 = 11. 4 \chi_{(6df)}^{2} = 11. 4 , P = 0.08), the order of preference was Moist Mixed forests > Mixed forests > Savanna habitats > Teak-Acacia-Zizyphus-Anogeissus forests > Acacia-Lannea-Boswellia forests > Thorn and Scrub forests > Agriculture areas. Habitat preference during the day was for dense vegetation (c(6df)2 = 35 \chi_{(6df)}^{2} = 35 , P < 0.001). At night lions even ventured into agricultural fields. Our data suggests that dense habitats are preferred by lions in Gir to escape the heat of the day and to be in good cover when human activity was likely to be at its peak within forested areas.  相似文献   

20.
《Ostrich》2013,84(3-4):175-184
We detail the sizes, spatial distributions and trends in nest site selection of cliff-nesting raptor and raven populations resident in the mountains of the Cape Peninsula, South Africa. We also assess the conservation value of these populations to inform the future management of the newly-established Table Mountain National Park (TMNP), and examine the structure and interrelations within the raptor community. The combined number, dispersion and density of nests (n = 96 nests, mean inter-nest distance = 0.59km, density = 30.0 pairs/100km2) are comparable with those of high-density raptor populations studied elsewhere in Africa and the world. Densities of Verreauxs' Eagle Aquila verreauxii (n = 2, 12.01km, 0.6 pairs/100km2, respectively) and Jackal Buzzard Buteo rufofuscus (n = 9, 4.63, 2.8 pairs/100km2), are low, Rock Kestrel Falco rupicolus (n = 44, 1.75km, 13.8 pairs/100km2) high and Peregrine Falcon Falco peregrinus (n = 19, 3.13km, 5.9 pairs/100km2) exceptional, relative to populations of the same or similar species in other areas. There are no comparable data for White-necked Raven Corvus albicollis (n = 22, 3.22km, 6.9 pairs/100km2). All species combined, and Peregrines in particular, significantly prefer high cliffs from the available habitat. Peregrines generally dominate the other species, may affect cliff site selection and dispersion in the rest of the community, and tend to locate their nests close to those of White-necked Ravens. Numbers of Verreauxs' Eagle are lower than recent historical levels, perhaps because key prey populations are depleted. Any future recovery of this large predator could subtly affect the entire assemblage. This cliff-nesting raptor community is a significant asset of the TMNP, and should be considered in management decisions taken in the Park, particularly those concerning the regulation of leisure activities in the vicinity of nesting areas.  相似文献   

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