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1.
Red foxesVulpes vulpes (Linnaeus, 1758) were experimentally removed in two nearby areas located in western Poland to verify the hypothesis about the limiting impact of their predation on the low-density population of brown haresLepus europaeus (Pallas, 1778) (4.4-10.6 ind./km2 in late autumn). In 1996/1997–2001/2002 foxes were culled (mainly in autumn and winter) in the reduction area (32 km2), whereas in the control area (34 km2) intensive culling was carried out only in 2000/2001–2001/2002. Indices of fox and hare spring densities were estimated using spotlight counts, as mean numbers of individuals observed per 10 km of the counting route. Annual changes in the fox density indices were negatively correlated with the bag of foxes, and annual changes in the hare density indices were negatively related to the annual changes in fox density indices. The fox density indices were significantly lower in the reduction area than in the control one only in 2000–2001 (2.8 times, on average), and in the same years, the hare population responded with higher density (1.7 times, on average). The hare responses took place without time delay, which suggests that the changes in fox abundance affected the situation of hares primarily in the autumn-winter season.  相似文献   

2.
Increases in red foxVulpes vulpes (Linnaeus, 1758) numbers and densities have been found in all European countries involved in the rabies vaccination program. In Poland, the number of foxes has increased steadily since the 1990s. Between 1999–2000, the average density of foxes reached 1.3–2 ind./km2 in some parts of the country. The aim of the study was to estimate the change in fox population densities in central Poland during 1980–2006, and to assess the effect these changes have had on the spatial distribution of natal dens, mean numbers of cubs observed at occupied dens and the sedentary/nomadic fox ratio. Estimations of fox population density and numbers were based on three methods: (1) counts of tracks in snow, (2) locations of natal dens and counts of cubs, and (3) the battue (driving) method. The three methods of assessment were used continuously in our study area over a period of 25 years. Average yearly results were analysed and comparisons made between the periods before and after implementation of the anti-rabies vaccination. The results obtained with all three methods show a significant increase in the fox population, when the two analysed periods are compared. Increases in fox population densities correlated with increased numbers of breeding sites being located outside forests, from only single ones in the 1980s to 24% of the total in 2005. The average number of cubs per occupied den decreased significantly (by 11%) in comparison with before the anti-rabies vaccination period. The great increase (more than 100%) in fox numbers observed using the battue (driving) method suggest, that nomadic animals can form an important part of winter population in our study area.  相似文献   

3.
Habitat management should be an important part of the brown hare (Lepus europaeus) conservation, but the habitat requirements of this species are not fully recognised. The aim of our research was to estimate these requirements by analysing the effect of various agricultural landscape structure features on the distribution of hares in five agricultural areas in Germany and Poland. The local density of hares was assessed in the spring and autumn of 2006 by using the method of spotlight–strip counts on 9–15 subareas in each research region. The structure of agricultural landscape has been described for each subarea: the share of grain, other crops and grasses as well as the density of crop edges and uncultivated places with wild vegetation. The density of hares was considerably higher in Germany than in Poland (18.8–48.4 vs. 4.1–9.5 indiv./km2). The hare density was positively correlated with non-grain crops in an area, with crop edges in two areas and with wild vegetation without trees in two areas, and negatively correlated with grassfields in two areas. The occurrence of wild vegetation without trees affected the hare density only in the study areas, where this habitat was relatively rare (<3 km/km2). It was suggested that proper projects aimed at habitat management for brown hares should be elastic, i.e. the projects should be modified depending on the structure of local landscapes. Moreover, the protection and creation of structures with wild vegetation among cropland seem to be considerable methods of brown hare or generally wildlife conservation; therefore, such measures should be an important part of agro-environmental packages.  相似文献   

4.
We investigated diet composition, habitat selection and spatial behaviour of the red fox (Vulpes vulpes) in relation to the availability of wader nests in a coastal polder area in southwest Denmark. The predatory role of the red fox in wet grassland ecosystems has profound implications for conservation status of declining populations of grassland breeding waders. However, few studies have focussed on the foraging ecology and behaviour of the red fox in these landscapes. Faecal analyses revealed that fox diet consisted of birds (43 % of prey remains?/?32 % of biomass), rodents (39 %?/?21 %), sheep (mainly as carrion, 14 %?/?41 %) and lagomorphs (4 %?/?7 %). Charadriiformes (including waders) comprised 3–12 % of prey remains throughout the year. Telemetry data and spotlight counts indicated that foxes did not select areas with high densities of breeding waders, suggesting that foxes did not target wader nests while foraging. Foxes maintained stable home ranges throughout their lives, indicating that the area sustained a permanent fox population all year round. The population densities, estimated from spotlight surveys, were 0.74 visible foxes km?2 (95 % CI; 0.34–1.61) on the preferred breeding habitat for waders and 1.21 km?2 in other open habitats such as cultivated fields. Our results indicate that red fox predation on wader nests is incidental, consistent with the notion that red foxes are generalist predators that opportunistically subsist on many prey groups.  相似文献   

5.
The aim of this study was to estimate long-term changes in the winter feeding pattern of red foxes Vulpes vulpes and in their predation on brown hares Lepus europaeus in relation to the decreasing abundance of hares in western Poland in 1965/1966–2006/2007. The frequencies of occurrence in the stomachs of culled foxes (N?=?726) were used as indices of prey capture rates. The average autumn density of brown hares in the study area decreased from 48 individuals/km2 at the turn of the 1960s and 1970s to seven individuals/km2 in 1999–2006. Hares and small rodents were the main food classes of foxes in western Poland at the turn of the 1960s and 1970s; however, the occurrence of hares in the fox diet subsequently decreased, and they were replaced by livestock carrion. The relationship between the occurrence frequency of hares in the fox diet and the hare density was best described by sigmoid equation. It indicates that the red fox showed a type III functional response to long-term changes in hare abundance. When predation rate index was estimated on the basis of functional response, the potential fox predation was density-dependent at low to intermediate hare densities (<25 individuals/km2). This finding suggests that the increase in the number of low-density hare populations may require intensive management measures, e.g. simultaneous use of fox control and habitat improvement.  相似文献   

6.
山西五鹿山保护区褐马鸡种群密度调查   总被引:12,自引:0,他引:12  
1997年12月-1998年3月对山西五鹿山保护区的褐马鸡种群密度进行了调查。越冬期和繁殖期的种群密度分别为12.67只/km^2和7.39只/km^2。通过对三个地区繁殖密度的比较,发现五鹿山地区繁殖种群密度偏低。这可能与该地区栖息地的质量日益恶化有关。  相似文献   

7.
2010年12月至2011年2月,在新疆哈密山区,采用截线抽样法和遥感技术,对野生天山马鹿(Cervus elaphus songaricus)种群现状和冬季生境选择进行了研究。在不同区域和不同类型栖息地共布设了28条样线,样线总长度达60.1 km。其中,16条样线上发现马鹿共233头,调查区域平均种群密度(2.83±1.01)头/km2,种群数量(1 684.56±379.71)头,与1993年的调查结果相比有所上升。雌雄性比为2.24:1,幼体和亚成体总数多于成体和老体总数,种群数量呈增长趋势。根据野外考察GPS数据并解译天山马鹿分布生境2006秋季的LANDSAT TM/ETM+遥感影像,将生境要素分为山地针叶林、草甸、灌木丛、农田和戈壁5种类型,其中,草甸与山地针叶林为天山马鹿冬季适宜生境。  相似文献   

8.
A detailed knowledge of the habitat requirements of steppe birds living in farmland habitats is necessary to identify agricultural practices compatible with their conservation. The globally threatened Great Bustard Otis tarda is a partial migrant in central Iberia, but factors affecting its winter habitat use have not been identified. We assessed habitat differences between breeding and wintering areas and winter habitat selection of radiotagged migrant female Great Bustards in central Spain. Of 68 tagged females, 35% moved to wintering areas located 64.3 ± 24.0 km south of their breeding areas, and 80% wintered in a single area of c. 236 km2. A census of the population in this area identified it as one of the most important wintering areas of this species in the world, holding c. 1500 individuals. There were significant differences between breeding and wintering habitats of individually marked migrant females. Compared with breeding areas, wintering areas of migrant females were located further from roads and urban nuclei, had lower human population densities and area of urban developments, and a higher diversity of land‐use types, with less cover of cereals and more vineyards and olive groves. Within this area, radiotracked migrant females preferred sites with more vineyards and a lower land‐use diversity. Our results highlight the importance of traditional Mediterranean dry farmland mosaics, and suggest that different conservation strategies are needed for migrant and resident populations in winter to secure the conservation of suitable wintering habitat for Great Bustards in the Iberian Peninsula.  相似文献   

9.
Bird population density and their behaviour during non-breeding periods are determined mainly by meteorological conditions which force birds to use alternative strategies — migration to areas with more advantageous conditions or adaptation to existing conditions. During the 2002/03–2004/5 non-breeding seasons in the open habitats of the Kotlina Orawsko-Nowotarska valley (S Poland) studies on population dynamics, behaviour and habitat use of great grey shrike were conducted. Results were grouped into four meteorological periods (autumn, early winter, winter and early spring). Density changes were seen between subsequent seasons (from 0.34 to 1.9 ind./10 km), as well as between meteorological periods (from 0.48 to 2.70 ind./10 km). Perching was the most frequently observed behaviour. The foraging habitats used changed in frequency. In subsequent meteorological periods a decrease of open habitats used was noted with a simultaneous increase in afforestations used. These changes did not depend on lasting snow cover. Changes in vegetation type used during hunting were not observed. Great grey shrikes most frequently used natural perches (trees, shrubs and high vegetation).  相似文献   

10.
1. Foxes Vulpes vulpes probably did not occur naturally on the Isle of Man, but were present in small numbers in the mid 19th century. They were introduced again in the 1980s, and in 1990 the population was estimated at 120–300 individuals (20–50 per 100 km2) on the basis of field signs. We used a nocturnal spotlight transect survey technique to assess the status of foxes on the Isle of Man in September 1999. This method had previously been used effectively to estimate fox densities in populations as sparse as 16 per 100 km2. We surveyed a total of 852 km over a period of eight consecutive nights, during weather conditions which allowed excellent visibility. No foxes were seen. 2. By comparison with equivalent survey efforts in reference areas of mainland Britain, we conclude that post‐breeding fox density on the Isle of Man was certainly below 2.5 per 100 km2, implying a maximum of 15 foxes on the entire island. We estimate a probability of only 15–25% that a fox population of 1 per 100 km2 was present but not detected; this would be equivalent to only five or six individuals on the whole island. Foxes may even be entirely absent, although unsubstantiated sightings continue to be reported. 3. This finding is significant in understanding the ecology of the Isle of Man, and in planning the conservation of a number of ground‐nesting bird species there, as well as for farming interests, and for contingency planning against an accidental introduction of rabies.  相似文献   

11.
广东海丰鸟类自然保护区褐翅鸦鹃数量调查   总被引:2,自引:0,他引:2  
为掌握褐翅鸦鹃(Centropus sinensis)在广东海丰鸟类自然保护区的种群现状,提出有针对性的保护措施,2005年对保护区内褐翅鸦鹃数量行了调查.4个季节中,夏季记录的个体数最多(32只),其样线平均个体数与春季、秋季相比,差异性显著(P<0.05);夏季种群密度最大,达17.78只,km2,冬季仅为1.11只/km2.单次记录到的多为单只个体.不同季节在3个保护站记录到的褐翅鸦鹃数量存在一定的差异.总体上,东关联安围记录到的个体数最多.  相似文献   

12.
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   

13.
The abundance, density, and habitat use of roe deerCapreolus capreolus (Linnaeus, 1758) and mouflonOvis aries Linnaeus, 1758 were studied in a confined Mediterranean area in Greece with a dung survey based on the faecal accumulation rate (FAR) technique. Estimated density was modelled with generalized additive models using altitude, habitat type, and slope as potential covariates. Model selection among the set of candidate models was conducted based on their generalized cross-validation score. Roe deer had an estimated mean density of 13.9 ind./km2 and the best model included slope and habitat type as covariates. The mean density of mouflon in the study area was 22.1 ind./km2 and the best model used altitude and habitat type as covariates. For both species, the highest densities were encountered in abandoned cultivations and glades, followed by conifer forests, while the lowest densities were observed in maquis. However, use of open habitats by mouflon was much greater than it was for roe deer. The strong preference of mouflon (a grazer species) for open habitats that were abundant with grasses probably reflected food availability and contrasted with the more diverse habitat use by roe deer (a selective browser).  相似文献   

14.
The ecology and reproductive biology of the crab-eating fox (Cerdocyon thous) and the pampas fox (Lycalopex gymnocercus) were studied in Itapuã State Park, an Atlantic Forest fragment. In this study we describe their activity patterns (diel, lunar, and seasonal), reproductive period, density, spatial distribution, and habitat overlap. The crab-eating fox was more abundant than the pampas fox, occurring in all types of habitats and overlapping with the pampas fox only in the southern portion of the study area, covered by open vegetation. Both canid species presented nocturnal habits and C. thous showed no significant differences in activity among lunar phases or else year season. The density of C. thous was estimated to be 0.78 ind/km2. The crab-eating fox reproduced once a year, generating pups during spring (October to December). In comparison with C. thous populations from lower-latitude regions the relatively low density and one reproductive event per year that we observed are probably related to a colder climate, shorter photoperiod, and shortage of food resources in the winter, characteristic of southern Brazil.  相似文献   

15.
近年黑龙江省凤凰山国家级自然保护区野猪数量不断增长,人猪冲突加剧,保护区资源保护管理工作面临较大管理压力.为确定野猪种群的实际数量,同时评估该保护区的野猪的容纳量水平,以便为保护区管理局针对野猪的管理提供相关指导意见.2009-2010年冬季,在保护区采用样带调查、雪地足迹链跟踪和观察食痕的方法,并结合已有野猪生态研究确定野猪食性.野猪主要食物种类包括:木贼(Equisetum hiemale)、红松(Pinus koraiensis)果实松籽、胡桃楸(Juglans mandshurica)果实核桃、蒙古栎(Quecusmongolica)果实橡子、稠李(Padus racemosa)、榛子(Corylus heterophlla)、苔草(Carex spp.)、辽东葱木(Aralia elata).研究期间共布设长3-5km、单侧宽度50m、总长134 km的样带30条.调查中,每隔200 m布设10 m×10 m的大样方,并在每个大样方中央及四角布设1 m×1 m的小样方,共布设大样方350个,小样方1 750个.通过样方调查,统计野猪栖息生境当年可食植物枝条及其食物种类,然后计算其食物的总供给量,再结合食物营养成分,通过粗蛋白、粗纤维、粗脂肪的能量转换,按照每克粗蛋白和粗纤维的能量转换系数为16.74kJ、每克粗脂肪的能量转换系数为37.66 kJ,确定野外生境食物总能量供给.结合野猪冬季日营养需求,以能量为基础估算保护区野猪的营养容纳量.在种群密度调查过程中,通过足迹链判断个体方法为:单一清晰足迹链确定为一个体所留,30m内多条足迹穿越同一样带被认为是一个野猪群所留,调查中根据个体分开时的足迹链数确定野猪个体数,同时将粪便、卧迹、啃食痕迹作为个体判断的辅助信息.研究结果表明:凤凰山保护区内能够提供的总能量为7.375 ×107MJ,冬季平均每头野猪生存所需能量为(14 677.698±409.92) MJ,野猪营养容纳量为(1 006±28)头,种群密度为(3.79±0.11)头/km2.此外,调查中发现30余个野猪套及2头野猪被猎杀现场,反应出当地的人猪冲突较为严重.结合调查中发现的野猪套数量及野猪被猎杀概率,对野猪种群数量引入20%的死亡风险系数.最终确定凤凰山野猪种群的最适数量在(603±17)头左右,最适密度为(2.27±0.06)头/km2.通过样带法调查得出凤凰山自然保护区实际野猪种群数量为(596±155)头,密度(2.24±0.58)头/km2,已趋近营养容纳量.因此,野猪并未过量,不能采取狩猎等降低种群数量的措施,同时保护区也应对野猪种群进行持续监控,防止野猪种群过度繁殖以至成灾.  相似文献   

16.
张微  田颖  张亚琼  李杰  胡严 《动物学杂志》2024,59(3):349-357
红隼(Falco tinnunculus)被列为国家二级重点保护野生动物,是能同时适应农村和城市环境的小型猛禽,对维持城市生态系统稳定具有重要意义。2022年4月至7月,为在北京救助的7只红隼佩戴了卫星追踪器,追踪其活动轨迹,依据追踪的动物活动位点数据,采用净平方位移-时间曲线依次对各红隼的迁徙模式进行了判别,深入分析了迁徙红隼的迁徙时间、距离和路线等,并采用核心密度法分别计算了迁徙及留居型红隼95%及50%活动区面积。研究结果表明,在北京地区红隼的迁徙模式为部分迁徙,追踪的7只红隼个体(N01 ~ N07)中,4只为留鸟,1只为迁徙鸟,2只居留类型无法准确判断。N01为迁徙红隼,其度夏地和越冬地分别在内蒙古锡林郭勒盟和河北廊坊,此红隼秋季迁徙速度明显高于春季,其春季迁徙距离551 km,历时25 d,平均迁徙速度为22 km/d,而秋季迁徙距离412 km,历时2 d,平均迁徙速度为203 km/d,河北承德滦平县是其春季迁徙的重要中途停歇地。不同红隼个体间95%及50%活动区面积均存在较大差异,迁徙红隼N01 95%、50%活动区面积在度夏区分别为93.10 km2、17.50 km2,在越冬区分别为7.03 km2、0.99 km2;留居型红隼95%、50%活动区面积均值分别为1 165.34 km2、178.71 km2(n = 4),其中最大95%、50%活动区面积分别为4 320.26 km2(N02)、648.22 km2(N02),最小95%、50%活动区面积分别为2.80 km2(N03)、0.29 km2(N03)。本研究揭示了北京地区红隼的迁徙模式、迁徙路线、重要停歇地及活动区状况,为红隼的针对性保护和管理提供了科学依据。  相似文献   

17.
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   

18.
In 2005–2008, we radio-tracked 17 foxes in rural areas of Southern Germany. The mean home range size was 76.6 ha (95% MCP) or 138.9 ha (95% fixed kernel), and the built-up area formed an integral part of the home range. Home ranges of juvenile foxes were significantly smaller than home ranges of adult foxes. Gender-specific differences among adult foxes were not established. A minimum population density of 2.7 foxes per km2 and summer densities of up to 13.4 foxes per km2 were calculated. Therefore, the fox density was three to eight times higher than that of strictly rural foxes. Daytime resting sites of foxes were mostly found in forests (62.2%) and reedbed areas (20.6%). Of the resting sites, 14.8% were situated inside settlements, in fallow gardens or gardens of residents. During the day, foxes exhibited habitat preferences for forests and reedbed areas. A habitat structure that offers plenty of cover or dense vegetation is essential for its selection as a safe resting site. If this basic requirement is fulfilled, foxes also choose resting sites within settlements, and are not disturbed by human presence.  相似文献   

19.
Knowing how habitat determines the distribution of great apes is essential for understanding their ecology and conservation requirements. Habitats in the northern Lac Tumba Landscape where this study was conducted are mostly swamp and flooded forests, which types have been overlooked in many great ape surveys. This study describes and discusses patterns of bonobo and chimpanzee nesting sites across these habitat types in the general scope of habitat use by great apes. Considerable efforts were deployed to survey forests of the Ngiri Triangle (186 km), Bomongo‐Lubengo (126 km) and Bolombo‐Losombo (112 km). Great ape nesting site encounter rates (r) were calculated for Bonobos (r = 0.21 nesting sites km?1; Bolombo‐Losombo), chimpanzees (r = 0.11 nesting sites km?1; Ngiri Triangle) and (r = 0.02 nesting sites km?1; Bomongo‐Lubengo). Swamps and flooded forests dominated the three zones. Nesting sites were at the highest encounter rates in flooded forests; both great ape species were significantly associated with swampy and flood forests. Human signs did not influence the occurrence of nesting sites in these forests. These results confirm findings from other sites where great apes were observed using swamps; they suggest that future surveys include these types of habitat to avoid under‐estimating population sizes.  相似文献   

20.
To test flying fox adaptations to a habitat mosaic with extreme deforestation, the abundance, habitat choice and feeding behavior of the Pacific flying fox, Pteropus tonganus, were investigated across 16 islands of the Yasawa archipelago, Fiji. The habitat mosaic is formed by 4.3 percent tropical dry forest and 3.3 percent farmland, leaving exotic grasslands and stands of Leucaena leucocephala to overrun the vast majority of land. Pteropus tonganus abundance was high (5757 bats) despite deforestation and hunting. Roosting sites were restricted to native forest fragments. Grasslands and stands of L. leucocephala were completely void of bats at all times. The mean foraging density in farmland was four times higher than in forests and foraging competition was routinely observed in farmland but was extremely rare in forests. The author suggests that during the study, extensive foraging in farmland was supporting the high P. tonganus population. Additionally, the preferential foraging in farmland was responsible for the low foraging densities within forests and dramatically less intraspecies competition for forest resources. Further research is needed on seed dispersal within forests and to test for seasonal variations in bat abundance and feeding.  相似文献   

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