Long-term changes in the feeding pattern of red foxes Vulpes vulpes and their predation on brown hares Lepus europaeus in western Poland

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.     

Annual dynamics of den use by red foxesVulpes vulpes and badgersMeles meles in central Poland

This study on den use by red foxesVulpes vulpes (Linnaeus, 1758) and badgersMeles meles (Linnaeus, 1758) was conducted in central Poland (51°48’N, 19°53’E) over two years. We found a strong negative correlation between monthly den utilisation rate by foxes and air temperature (r=−0.83,p=0.0001). Correlation between temperature and den use by badgers was positive but less distinct (r=0.40,p=0.036). During the whole study period, a negative correlation between the monthly intensity of den use by badgers and by foxes was found (r=−0.51,p=0.008). The seasonal pattern of den utilisation differed between the species. Foxes used the dens mainly in winter and spring whereas in summer and autumn the intensity of den utilisation sharply decreased to a minimum in August-September. A peak in den use by foxes was observed in March and coincided with rut and selection of future breeding dens. In badgers, two peaks in den use were observed: the first in April and the second in August-September. An individual badger used more dens and used them more evenly throughout the year than an individual fox. The same dens were visited by foxes and badgers mostly from January to April, with a maximum in March.     

The effect of landscape structure on the distribution of brown hare Lepus europaeus in farmlands of Germany and Poland

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.     

Red foxVulpes vulpes density and habitat use in a rural area of western Poland in the end of 1990s, compared with the turn of 1970s

The red foxVulpes vulpes (Linnaeus, 1758) density and habitat use were studied in open farmland of western Poland, where forests covered only 6% of the area. During 1997-2000, nocturnal spotlight counts (in spring and early winter), the location of breeding sites and snow tracking were carried out, and the feeding habitat was described based on the stomach content of shot individuals. The average fox density estimated on the ground of spotlight counts was 1.02 individuals/km2 in spring and 1.63 ind./km2 in early winter, while the winter density obtained from the results of track counts was 1.26 ind./km². The average breeding population density, calculated as the double density of breeding sites (mean 0.31/km²), amounted to 61% of the average total spring density, which indicates the occurrence of surplus individuals in the population. The searching intensity of farmland by foxes did not changed with the increasing distance from forests, but relatively larger number of individuals was observed <0.5 km than 0.5–1.0 km away from settlements. Out of 81 identified breeding sites, 17% were located in forests and 83% in farmland. The predominant ingredients of the fox’s diet were farm livestock and small rodents (44.4 and 43.8% of the stomach content volume, respectively). The fox density in the study area was 5.4 times higher, compared with the turn of the 1970s, and changes in the habitat use consisted of more intensive occupation of open farmland and the use of human-produced food. Thus, these changes may have been among reasons of the increase in the fox density in western Poland.     

Echinococcus multilocularis in the red fox Vulpes vulpes from the East Carpathian region of Poland and the Slovak Republic

The occurrence of Echinococcus multilocularis in the Poland-Slovak frontier zone of the East Carpathian region was assessed, for comparison with that in adjacent regions in both countries. A total of 392 red foxes from Poland and 427 red foxes from the Slovak Republic were examined from 2001 to 2004. Significant differences in prevalences were observed in foxes captured from the borderland and adjacent zones in both countries. The mean prevalence of E. multilocularis in the Polish borderland reached 45.7+/-18.6% and in the Slovak border 35.0+/-10.7%. In both countries, the prevalence of E. multilocularis in red foxes from adjacent districts, outside the frontier Carpathian region, was considerably lower (18.9+/-9.2% in Poland and 20.8+/-9.0% in Slovakia). These differences are probably due to geomorphological and ecological factors, which contribute to the survival of the tapeworm eggs and the subsequent spread of infection. The Carpathian regions of northeast Slovakia and southeast Poland are characterized by specific climatic conditions such as low mean annual air temperatures, low temperatures in active soil surfaces, high soil humidities and a high mean annual rainfall.     

The effect of experimental anaemia on red cell glutathione reductase

The effect of experimental anaemia on red cell glutathione reductase (GR) was investigated in rabbits, guinea-pigs and cattle. The ratio of active and inactive forms of GR did not change during the experimental period in either the rabbits or the cattle. However, there was a marked rise in the ratio of inactive form in the guinea-pigs during anaemia. It appears that, in addition to the most important regulator of GR activity, namely the flavin content of the red blood cells, there are other mechanisms which are operating in the red blood cells of anaemic animals and that these mechanisms vary among different species of animals.     

Humans do matter: determinants of red fox ( Vulpes vulpes ) presence in a western Mediterranean landscape

Habitat loss, due to landscape changes induced by human activities, is considered one of the main drivers of biodiversity decline. Thus, understanding how these changes affect top trophic-level species is essential to develop effective conservation strategy measures to overcome this problem. Mesocarnivores, as higher trophic-level species with crucial roles in ecosystem functioning, are a pivotal functional group in such strategies. Generalist mesocarnivores, such as the red fox (Vulpes vulpes), are excellent models to study species ecological adaption to landscapes moulded by humans. Using generalised linear mixed model (GLMM), we aim to understand how the landscape context affects the presence of this generalist species, in a Mediterranean ecosystem (northeastern Portugal) characterised by a combination of natural areas and traditional agricultural land uses. Based on scats’ distribution, we generated distribution models to test different ecological hypotheses—anthropic disturbance factors, altitude and land-cover patterns. According to our results, red foxes seem to have two distinct strategies: in forest-dominated areas, human activities have a negative effect (disturbance); in areas with a low percentage of forests, agriculture patches and the proximity to urban areas are the main drivers determining its presence, with a positive influence (food availability). Our results confirm the opportunistic character of this species and its high degree of adaptation. Further, the outcome also reveals that landscape context influences the detected pattern. Consequently, considering that populations of the same species are constrained by the same factors, independently of the landscape composition, will affect the effectiveness of management measures that will not account for landscape context effects.     

Body size of the red fox Vulpes vulpes in Spain: the effect of agriculture

The body size of animals is affected by several factors, including ambient temperature and food availability. Ambient temperature is often negatively related to body size (Bergmann's rule) whereas an improved diet, especially during growth, has a positive effect. Animals commensal with man commonly exploit additional food sources (e.g. garbage dumps), thereby increasing their food supply. Using museum material, we studied morphological variation in skull size (and thus body size) among Spanish red foxes. Four measurements were taken of each skull and were related to the habitat from which the foxes were collected (agricultural and non-agricultural), and to latitude as a proxy for ambient temperature. The skull size of foxes collected in agricultural areas during the late 20th Century was significantly larger than that of those from non-agricultural areas, and was negatively related to latitude, thus contradicting Bergmann's rule. We suggest that increased food availability from animal husbandry is the cause for the observed increase in skull size (and thus body size).  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 90 , 729–734.     

Foraging and diet of the red fox Vulpes vulpes in relation to variable food resources in Biatowieza National Park, Poland

Feeding ecology of red fox Vulpes vulpes was studied by scat analysis and snow-tracking m primeval temperate forest and adjacent meadows during four years (1985/86-1988/89) Winters varied from mild to unusually severe Main food resources for foxes were rodents of open meadows and river valleys (root vole Microtus oeconomus ). forest rodents (bank vole Clethrionomys glareolus and yellow-necked mouse Apodemus flavicollis ), hare Lepus europaetis and carcasses of wild boar Sus scrofa and red deer Cervus elaphus either killed by wolves and lynx or that had died from inanition Composition of fox diet m four cold seasons (autumn-winter) was compared to the abundance of main food resources Prolonged, sharp decline of Microtus was followed by only a twofold decrease of its share in fox diet Foxes continued to prey on declining Microlus The changes in the proportions of forest rodents and hare in fox diet clearly followed the fluctuations in numbers of these two prey Carcasses were alternative, buffer food to foxes and were taken considerably when Microlus and other prey were in low numbers or poorly accessible The depth of snow was the most important factor restricting foxes access to rodents Snow-tracking revealed that foxes dwelling in the forest widely used adjacent open areas In open meadows foxes mainly hunted for rodents, while in the forest the most significant foraging activity was scavenging Seasonal analysis of fox diet revealed that consumption of Microlus by foxes was stable throughout the year (37-47% of biomass consumed) Bank vole significantly contributed to fox diet in autumn, and hare in summer only Scavenging was most pronounced in winter and spring when carcasses made up 30% of biomass taken     

Influence of the abundance of food resources on the feeding habits of the red fox, Vulpes vulpes, in western Switzerland

J.-M. WEBER
The influence of food abundance on red fox feeding habits was studied in the Swiss Jura Mountains between November 1990 and February 1992, during a low density period in the water vole population cycle. Six food categories–water voles, small mammals, domestic stock, earthworms, wild fruits and exploitable scraps–were censused during the present research and their seasonal abundances were estimated in fixed plots. Fox scats were collected and analysed at regular monthly intervals.
The diet of foxes was found to be correlated with seasonal food supply. A positive significant correlation between seasonal abundances and relative proportions in the diet was found for food categories showing a clear seasonality (earthworms, wild fruits and exploitable scraps), whereas no correlation was recorded for the other food resources. Diet composition observed in the present study was compared with that recorded in the same study area between 1988 and 1990 by Weber & Aubry (1993), when water voles were very common and accounted for more than 50% of the diet. A significant change was recorded in red fox feeding habits: the most important aspects of this modification of the diet was the decrease in water vole importance accompanied by the increase in the frequency of occurrence of other food categories, such as wild fruits and scavengeable items.     

The effect of drying process on undervalued brown and red seaweed species: elemental composition

Journal of Applied Phycology - The influence of drying (sun-drying and shade-drying) on the elemental composition of two brown seaweeds (Treptacantha abies-marina, Cystoseira humilis) and two red...     

Diet of the fox Vulpes vulpes in a western Victorian forest

The diet of foxes living in a mixed dry sclerophyll forest at Naringal East near Warrnambool, Victoria was investigated by analysis of scats collected between October 1972 and July 1975. The results indicate that foxes in the study area are opportunistic feeders whose diet consists mainly of rabbits despite the abundance of suitably sized native mammals and an even greater abundance of birds. During summer and autumn the foxes consume large numbers of insects, particularly the black cricket, Gryllus servillei, and the Australian plague locust, Chortoicetes terminifera, and blackberries.     

Outbreak of Cronobacter turicensis in European brown hares (Lepus europaeus)

This is the first report of acute deaths in five European brown hares (Lepus europaeus) attributed to mucoid and necrotizing typhlocolitis caused by genetically different Cronobacter (C.) turicensis strains in northeastern Austria. As this opportunistic pathogen is mainly known for causing disease in immunocompromised humans and neonates, this previously unrecognized potential for a spill over from a wildlife reservoir to humans warrants further attention.     

稻菜轮作对稻田褐飞虱和蜘蛛数量的影响

在广东省广州市花都区和白云区系统调查了稻菜轮作田、水稻连作田的水稻害虫褐飞虱Nilaparvata lugens(Stl)及其捕食性天敌蜘蛛的数量,结果表明:与水稻连作相比,花都区稻菜轮作模式总体上降低了褐飞虱数量,同期最高降低66.6%,对田间蜘蛛数量影响不明显;白云区的稻菜轮作模式也显著降低了褐飞虱的数量,同期最高降低56.3%,对蜘蛛数量的影响也不明显。稻菜轮作模式能有效降低田间褐飞虱数量,有利于水稻生产。     

辽西半干旱区农田水肥耦合作用对春小麦产量的影响

最优饱和设计试验建立的春小麦产量回归数学模型表明,水分是影响辽西半干旱区春小麦产量最为重要的因子,但在自然降水条件下,灌水量上、下限分别为４５ｍｍ和３６０ｍｍ时,Ｎ对春小麦产量影响更为敏感,其次为水与Ｐ因子,三因子对小麦产量影响统计分析达显著水平,并且其对小麦产量的影响符合报酬递减率,获得最大利润时,Ｎ、Ｐ和水三因素最佳经济配比模式为施Ｎ量１８６ｋｇ．ｈｍ＾－２,施Ｐ量６３ｋｇ．ｈｍ＾－２,灌水量     

Beta hemolytic streptococcal infection in red foxes (Vulpes vulpes L.) in France: the natural disease and experimental studies

Beta hemolytic streptococcal infections, usually of group G and C, were identified in red foxes in France. In a study of 31 animals, septicemia and jaundice were found to be the main signs of the disease. Gross and microscopic lesions consisted of generalized inflammation of viscera and joints, jaundice, cellulitis and abscesses of spleen, liver, lungs and kidneys. The disease was reproduced in foxes by intramuscular inoculation of less than the minimal quantity of bacteria lethal to mice. When challenged, recovered animals were resistant to infection that proved to be lethal to control animals.