European brown hare syndrome virus in free-ranging European brown hares from Argentina

From 1998 to 2000, serum samples of 80 shot European brown hares (Lepus europaeus) from Argentina were examined for antibodies against European brown hare syndrome virus (EBHSV) and 80 spleen samples were tested for EBHSV-antigen by enzyme linked immunosorbent assay (ELISA). Nine hares were positive for EBHSV-antigen. Antibodies against EBHSV were detected in only one individual. Based on negative staining electron microscopy of spleen homogenates, we observed calicivirus in one of five EBHSV-antigen positive hares. However, EBHS has not been reported to cause abnormal mortality in these hares. This is the first report of antibodies to EBHSV, EBHSV-antigen, and electron microscopy findings in free-ranging European brown hares from South America.     

European brown hare syndrome in free-ranging European brown and mountain hares from Switzerland.

From 1997 to 2000, complete necropsy and histopathologic investigations were performed on 157 free-ranging European brown hares (Lepus europaeus) found dead throughout Switzerland. Organ samples of all these individuals (157 livers and 107 spleens available) were tested for European brown hare syndrome virus (EBHSV)-antigen by enzyme-linked immunosorbent assay (ELISA) test kit. Furthermore, 60 additional blood samples were tested for antibodies against EBHSV by ELISA. In addition, liver samples of 87 free-ranging mountain hares (Lepus timidus) hunted in 1996 were tested for EBHSV-antigen. In two European brown hares from southern Switzerland lesions suggestive of changes induced by EBHSV were present, and high titers of EBHSV-antigen were detected in both liver and spleen samples of these animals. Based on negative staining electron microscopy investigations of liver and spleen homogenates, we observed calicivirus in one antigen-positive hare. Low EBHSV-antigen titers were found in three additional European brown hares from central and western Switzerland, but EBHS-lesions were absent. Antibodies against EBHSV were not detected in any of the sera of European brown hares, and EBHSV-antigen was not found in the samples of mountain hares. This is the first report of EBHS in European brown hares from Switzerland.     

Thirty‐four polymorphic microsatellites for European roe deer

The European roe deer (Capreolus capreolus) is an interesting model for molecular ecology studies because of its abundance and adaptability across a range of environments (including human‐modified habitats), and because of its increasing impacts on agricultural crops and on regenerating forests. We identify polymorphic microsatellites in two managed populations of roe deer in France by using cross‐species amplification of primers from other Cervids and from Bovids. Of the 62 primer pairs tested, 45 amplified microsatellites in roe deer, and 34 were polymorphic. Eleven primer pairs were selected for multiplex gel‐loading for routine genotyping of the studied populations.     

Food competition between a large ruminant and a small hindgut fermentor: the case of the roe deer and mountain hare

In this study, we demonstrate that the mountain hare and roe deer compete with each other. This was determined using "natural experiments" of populations found in sympatry and allopatry on the islands along the west coast of Norway. We demonstrate that both species occupy the same habitats, share the same food resources and that food availability is limited. Two browsing species as different in size as roe deer and mountain hare might be expected to partition the available vegetation (e.g. woody scrub) in terms of height above ground level. However, from the evidence collected, the feeding-height-separation hypothesis must be rejected as an explanation for ecological separation between roe deer and mountain hares because there was extensive height overlap in resource utilisation by both species and neither species changed its feeding height in response to the presence of the other. Total browse utilisation did not increase when both species were together; rather, species-specific browse utilisation declined when the other species was present. However, the foraging behaviour of each herbivore varied significantly between the allopatric and sympatric sites. When both herbivores were present, the clip diameter of shoots browsed by mountain hares declined to match those selected by roe deer, while roe deer switched from a browse-dominated diet to a diet dominated by winter-green gramineae. The change to smaller-diameter shoots likely resulted in the hare increasing its intake of digestion-inhibiting or toxic secondary metabolites, while the alternative choice of digging through the snow like roe deer to reach the winter-green gramineae is a practice considered energetically too costly for hares. On this basis, we conclude that the enforced switch to a nutritionally inferior diet by mountain hares at the sympatric sites may result in changes to growth rate and body size which consequently impact on mortality and may explain the competitive superiority of the roe deer.     

Unilateral hydrocephalus in a wild European brown hare (Lepus europaeus)

Macroscopic and histological study of a case of unilateral hydrocephalus in a young wild European brown hare (Lepus europaeus) is reported here. Morphological changes were mostly massive dilatation of the left lateral ventricle, atrophy of the cortex and a striking reduction of the corresponding white matter. Lymphocytic cell infiltrates and hemosiderin-laden macrophages in the choroid plexus and meninges also were observed. Although the exact cause of the lesions was not found all findings suggested a hydrocephalus of possible traumatic, infectious or congenital hypoplasia origin.     

Temporal dynamics of European brown hare syndrome infection in Northern Italian brown hares (Lepus europaeus)

The progressive decline in the hare population across Europe has been associated with the occurrence of European brown hare syndrome (EBHS), a highly contagious disease considered endemic in all European countries. This study aimed to evaluate the in-field temporal dynamics of European brown hare syndrome virus (EBHSV) infection in wild European brown hares (Lepus europaeus) and to test the influence of population density on EBHS seroprevalence. A total of 512 blood samples were collected from free ranging hares captured for restocking in seven different areas of the province of Brescia (Northern Italy) during seven consecutive years (2006–2013) and tested using a competitive ELISA. A generalized linear mixed model estimated the yearly effects of population density on EBHS prevalence. Of the 512 tested, 344 (67.2 %) tested positive for EBHSV antibodies, with the annual seroprevalence ranging from 94.3 to 35.8 %. The prevalence was 3.303 times higher in areas with a density of over 15 hares/km² and declined over the years. The results indicate the ongoing transmission of the virus in the tested brown hare population. Since the eradication of EBHS in a wild population is not feasible, a strategy aimed at promoting the endemic stability of the virus through density-dependent mechanisms could be applied; however, this seems more difficult in practice than in theory and would most likely require a very high density of brown hares.     

Cladogenesis of the European brown hare (Lepus europaeus Pallas, 1778)

A substantial portion of today’s biodiversity is attributed to the climatic oscillations of the Pleistocene Ice Ages. Gradual but dramatic climate changes were accompanied by expansion, contraction, and isolation of populations, promoting the accumulation of genome differences and adaptations in refugial populations and resulting in allopatric differentiation in a variety of taxa. In the present study, partial mitochondrial DNA sequences of the widely distributed European brown hare (Lepus europaeus) were analyzed to test whether the species’ present genetic structure is the result of postglacial re-colonization of Europe from Asia Minor (clade A) and the Balkans (clade B) only, as suggested previously, or if additional refugia are likely. Analyses indicated the presence of an additional refugium (Italy, clade I). The genealogic network of Italian hares displayed the tree-like structure expected from refugial populations, whereas central European brown hare haplotypes revealed a clear star-phylogeny indicative of past-bottleneck population growth. This population size expansion, which was confirmed by mismatch analysis, was estimated to have occurred ∼50–55 thousand years ago (kya). The divergence of clade A* from the remaining matrilines is estimated at 239 kya, whereas the divergence of the ancestors of clades B* and I from A* occurred about 128 kya. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Acute hepatosis in the European brown hare (Lepus europaeus) in Italy.

Since October 1986 an unusually high mortality has been observed both in wild European brown hares (Lepus europaeus) and in hare farms in Italy. Pathological alterations, including severe hepatosis, nephrosis, congestion and hemorrhages of tracheal mucosa and lungs, and splenic vascular congestion, were observed in 179 of 381 hares necropsied from 1986 to 1988. Jaundice also was seen in 30% of these hares. Histologically, the liver damage was characterized by coagulative necrosis, mainly located around the portal areas, or by degenerative changes. Hyperemia, focal hemorrhages and periportal mononuclear cell infiltration were also present. The epithelium of renal tubules showed the presence of various degrees of vacuolar degeneration and necrosis, and eosinophilic granular hyaline casts or homogenous proteinaceous material were found within the lumen of tubules. Only the adult hares were affected. In wild hare populations night counts revealed a reduction of the number of observed wild hares during the winter period which ranged from 27 to 40%, whereas in hare farms the mortality ranged from 30 to 90%. Bacteriological, parasitological, and toxicological investigations were unable to confirm the primary cause of these deaths. Negative stain electron microscopy and immunoelectronmicroscopy conducted since October 1988 on liver and spleen homogenates from hares with acute hepatosis revealed the presence of viral particles with morphological aspects resembling those of calicivirus, antigenically related to the etiological agent of viral haemorrhagic disease of rabbits.     

Dispersal is not female biased in a resource-defence mating ungulate, the European roe deer

Dispersal is frequently more prevalent in one sex compared to the other. Greenwood proposed that patterns of sex-biased dispersal among birds and mammals are linked to their mating strategies. For species where males defend resources rather than females, he predicted female-biased dispersal, because males should remain at their birth site where they are familiar with the distribution of the resources that they must defend. Greenwood's hypothesis has been extensively supported among birds, where most species exhibit a resource-defence mating strategy. However, almost no equivalent information is available for mammals as males generally defend mates in this group. An exception is the European roe deer, a resource-defence mating ungulate. We thus tested Greenwood's hypothesis on this atypical mammalian model, looking for female-biased dispersal using sex-specific inter-individual genetic distances. We conclusively show that gene flow is not higher among females compared to males in the studied roe deer population, and hence that dispersal is not female-biased, suggesting that male mating strategy is not the primary selective force driving the evolution of dispersal in roe deer. We discuss the role of female mate choice and intra-sexual competition as possible alternative selective pressures involved.     

High red deer density depresses body mass of roe deer fawns

Many previous studies have pointed out that, when resources are limited, the potential for competition should be high among sympatric species that display overlaps in habitat and nutritional niches. However, reliable evidence of competition between red deer (Cervus elaphus) and roe deer (Capreolus capreolus) has not been yet reported for life history traits directly measuring performance such as body mass, reproduction, or survival. From long-term monitoring of deer populations in the reserve of La Petite Pierre (France), we measured the sex-specific responses of roe deer fawn body mass to changes in red deer density after accounting for possible confounding effects of date of shooting, climatic conditions, and roe deer density. As expected under the hypothesis of competition, red deer density in a given year had a marked negative influence on body mass of roe deer fawns born the same year and the following year. Fawn mass of roe deer males and females responded in similar ways to changes in red deer density. Our study provides the first evidence of a negative response of roe deer performance to high red deer density.     

No difference between the sexes in fine-scale spatial genetic structure of roe deer

Background

Data on spatial genetic patterns may provide information about the ecological and behavioural mechanisms underlying population structure. Indeed, social organization and dispersal patterns of species may be reflected by the pattern of genetic structure within a population.

Methodology/Principal Findings

We investigated the fine-scale spatial genetic structure of a roe deer (Capreolus capreolus) population in Trois-Fontaines (France) using 12 microsatellite loci. The roe deer is weakly polygynous and highly sedentary, and can form matrilineal clans. We show that relatedness among individuals was negatively correlated with geographic distance, indicating that spatially proximate individuals are also genetically close. More unusually for a large mammalian herbivore, the link between relatedness and distance did not differ between the sexes, which is consistent with the lack of sex-biased dispersal and the weakly polygynous mating system of roe deer.

Conclusions/Significance

Our results contrast with previous reports on highly polygynous species with male-biased dispersal, such as red deer, where local genetic structure was detected in females only. This divergence between species highlights the importance of socio-spatial organization in determining local genetic structure of vertebrate populations.     

Lead concentrations and lead and strontium stable-isotope ratios in teeth of European roe deer (Capreolus capreolus)

The study reports lead concentrations and lead and strontium stable-isotope ratios in mandibular molars of roe deer from three different areas in western Germany. Lead concentrations in third molars ranged between 0.23 and 36.61 μg/g (dry weight). Comparing lead concentrations in first molars and third molars in a group of ca. 1.5- or ca. 2.5-year-old individuals from the same area revealed an effect of tooth age on tooth lead content. The higher lead concentrations in the first molars were attributed to the longer period of lead accumulation by the dentin of these teeth compared with the later-forming third molars. Differences in lead isotopic signatures of the teeth were observed between the three areas, presumably reflecting variation in exposure to different sources of environmental lead. We also found marked variation in the ⁸⁷Sr/⁸⁶Sr isotope ratios of the teeth, with only a small overlap in values between two of the areas. Strontium isotope analysis alone or in combination with lead isotope analyses can be a useful means of assessing the provenance of deer teeth of unknown geographical origin.     

Descriptive epidemiology of roe deer mortality in Sweden

A retrospective epidemiologic study was conducted to examine causes of mortality of 985 wild roe deer (Capreolus capreolus) submitted to the National Veterinary Institute (SVA; Uppsala, Sweden) from January 1986 to December 1995. Age, sex, body condition, and geographic distribution as related to disease conditions are reported herein. The most common causes of mortality in roe deer were trauma (19%), winter starvation (18%), gastritis/enteritis (15%), bacterial infections (11%), parasitic infection (11%), systemic diseases (11%), neoplasia (2%), congenital disorders (1%), and miscellaneous causes (6%). Cause of death was not determined in 6% of the cases. The distribution of causes of death reported in this study differ from previous works in Sweden in that infectious and parasitic diseases were more common than winter starvation. The pathologic findings in studies like this do not necessarily represent what is occurring in the natural environment, but they do provide a good indication of distribution of diseases over time as well as age and sex structure in relation to disease conditions. Further research and more detailed studies are in progress to better understand specific mortality factors as well as etiologies of certain described diseases in roe deer in Sweden.     

Polydactyly in roe deer (Capreolus capreolus)

Supernumerary digits on roe deer (Capreolus capreolus) have been recorded over many decades in Germany. The case described in this communication is believed to be only the second documented example from the UK. A right hind foot of a buck had three equally developed digits arising from a metatarsal that trifurcated.