1. The ecology and status of fin whales Balaenoptera physalus in the Mediterranean Sea is reviewed. The species’ presence, morphology, distribution, movements, population structure, ecology and behaviour in this semi-enclosed marine region are summarized, and the review is complemented with original, previously unpublished data.
2. Although the total size of the fin whale population in the Mediterranean is unknown, an estimate for a portion of the western basin, where most of the whales are known to live, was approximately 3500 individuals. High whale densities, comparable to those found in rich oceanic habitats, were found in well-defined areas of high productivity. Most whales concentrate in the Ligurian-Corsican-Provençal Basin, where their presence is particularly noticeable during summer; however, neither their movement patterns throughout the region nor their seasonal cycle are clear.
3. Based on genetic studies, fin whales from the Mediterranean Sea are distinct from North Atlantic conspecifics, and may constitute a resident population, separate from those of the North Atlantic, despite the species’ historical presence in the Strait of Gibraltar. Fin whales are known to calve in the Mediterranean, with births peaking in November but occurring at lower rates throughout the year. They feed primarily on krill Meganyctiphanes norvegica which they capture by diving to depths in excess of 470 m. It is suggested that the extensive vertical migratory behaviour of its main prey may have influenced the social ecology of this population.
4. Known causes of mortality and threats, including collisions with vessels, entanglement in fishing gear, deliberate killing, disturbance, pollution and disease, are listed and discussed in view of the implementation of appropriate conservation measures to ensure the species’ survival in the region.
The Eurasian Badger occurs throughout the Palaearctic, and in all states of Europe west of the border with the former Soviet Union. Within this area it is absent only from the arctic zones, high-altitude areas, and some islands. The Badger is currently a protected species in the UK, the Irish Republic, Spain, Portugal, Italy, Belgium, the Netherlands, Albania, Greece, Estonia, Luxembourg and Hungary, but Luxembourg and Hungary are to reconsider protected status. Elsewhere, the species is either considered as small-game or as a pest, hunting being regulated by closed seasons. At present Finland and Burgenland (Austria) afford protection to breeding females, whilst Bulgaria, Macedonia and the Austrian Bundeslnder of Steiermark and Salzburg permit Badger hunting throughout the year. Where the species is protected, provisions usually exist for the removal or culling of ‘pest’ individuals. The official European game-bag currently totals about 118,000 Badgers, but poaching is common, particularly in the UK and Ireland. Published population estimates, coupled with national population minima obtained by extrapolation from game-bag statistics, indicate a minimum European Badger population of 1,220,000; the true figure may exceed this considerably. Badger populations appear to be either stable or increasing throughout much of Europe, although no data are currently available for the populations of Greece, Italy, Spain, Croatia, Bosnia-Hercegovina and Portugal. Badgers are uncommon in the Netherlands, Estonia, Belgium, the Slovak Republic, and possibly Poland. Only the populations of Albania and possibly of some parts of the former Yugoslavia appear to be decreasing. The Dutch population remains at considerable risk, despite modest recent increases. The population status of the endemic sub-species of Crete and Rhodes remain uncertain and require urgent clarification. A series of management recommendations are proposed to improve the status of the Badger in Europe.
The normal anatomy of the distal part of the Sperm Whale penis is described from an adult male that stranded in the Firth of Forth, Scotland in 1997. However this individual had experienced a blockage and subsequent rupture of the penile urethra that probably led to its death, so that the structure of the basal part of the penis was obscured. The anatomy of the Sperm Whale penis is similar to that of most other cetaceans that have been examined.
1. At the end of the Last Glacial Maximum brown bears Ursus arctos recolonized the glacial landscape of Central and Northern Europe faster than all other carnivorous mammal species of the Holocene fauna. Ursus arctos was recorded in Northern Europe from the beginning of the Late-Glacial. The recolonization of northern Central Europe may have taken place directly after the maximum glaciation. The distribution of the brown bear was restricted to glacial refugia only during the Last Glacial Maximum, for probably no more than 10 000 years.
2. Genetic analyses have suggested three glacial refugia for the brown bear: the Iberian Peninsula, the Italian Peninsula and the Balkans. Subfossil records of Ursus arctos from north-western Moldova as well as reconstructed environmental conditions during the Last Glacial Maximum in this area suggest to us a fourth glacial refuge for the brown bear. Because of its connection to the Carpathians, we designate this as the ‘Carpathian refuge’.
3. Due to the low genetic distance between brown bears of northern Norway, Finland, Estonia, north-eastern Russia and the northern Carpathians (the so-called eastern lineage), the Carpathians were considered the geographical origin of the recolonization of these regions. During the recolonization of northern Europe the brown bear probably reached these areas rapidly from the putative Carpathian refuge.
The Wild Boar Sus scrofa L. is widely distributed in Europe, Asia and North-West Africa. It has also been introduced into the USA and Argentina. Authors have described 22 subspecies on the basis of cranium shape and size. Differences in taxonomic characters have been evaluated using one-way ANOVA and multiple comparisons have been performed with the Bonferroni Test. Cranium shape does not allow reliable statistical distinction, and is not valid as a diagnostic tool. Cranium profile-which only differs for the male specimens, with populations differing at a value of 26.9%, or at the subspecies level 24.4%–cannot be used as a diagnostic tool. The length, width and their proportions of the third upper molar tooth show the following differences between subspecies: 39.1%, 41.0% and 8.3% for males and 36.1%, 41.7% and 16.7% for females, respectively. Only the first two criteria are useful as diagnostic tools. The percentage distance between the palatum durum and the basipterygoideus suture, the length of the third lower molar tooth and proportion between the height of lacrimal bone at the orbit and its lower suture length differ as follows: at the subspecies level 46.7%, 38.5% and 56.4% for the male specimens and 36.1%, 45.8% and 55.6% for the female ones. All of these characters can be used as diagnostic criteria. Taking these taxonomic characters and the four shapes of the lacrimal bone together with the rear margin of palatum durum as a basis, only four subspecies of Wild Boar are recognizable: Sus scrofa scrofa, inhabiting North-West Africa, Europe and West Asia; Sus scrofa ussuricus, which inhabits North Asia and Japan; Sus scrofa cristatus, which inhabits the Asia Minor peninsula, India and the Far-East; and Sus scrofa vittatus, which inhabits Indonesia.
The trophic status of the European Polecat Mustela putorius was studied through a review of the diets of 18 different populations in Europe. Rodents represented the principal prey in 10 sites (55.5%) and were a prey of secondary importance in seven sites (38.8%). Anurans prevailed in three sites (17%) but constituted the second food category in eight others (44%). The ascendant hierarchical classification showed a relatively unvarying diet in Europe. The frequency of birds and invertebrates were important in the diversification of the diet, indicated by the value of the food niche index, whereas rabbits were more significant in southern regions. The constant incidence of predation on woodland rodents and amphibians gave a particular status to the Polecat and showed it to be a generalist feeder well adapted to the mid-European region.
ABSTRACT • Populations of wild goats that can be referred to as phenotypes of the pasang, or Bezoar goat, or wild goat Capra aegagrus Erxleben, 1777, still occur on several of the Mediterranean and Eastern Atlantic islands. Other populations became extinct not many decades ago. • Fossil evidence for the natural spread of the wild goat to any of these islands has not been found. Originating in the Near East, the region of its natural range and its earliest domestication, the species was introduced by humans onto the Mediterranean islands starting as early as the Pre-Pottery Neolithic. • The islands of the Eastern Atlantic were colonized artificially by animals of ‘pre-Hispanic’ origin. The principal phenotypes expressed by all these populations of goats can be matched with the characteristics of both C. a. aegagrus Erxleben, 1777 (aegagrus phenotype) and C. a. dorcas Reichenow, 1888 (dorcas phenotype). • Most of these animals currently survive on the islands without being fed by humans, and should be protected.
A spot distribution map of Dryomys nitedula in Europe is presented, based on a critical evaluation of published information from the various countries of Europe. In addition, maps which are numbered to identify localities were prepared for regions where Dryomys nitedula distribution was largely unknown until now. The species has a unique distribution, ranging from the Alps in the west to the foothills of the Urals in the east, and from southern Latvia in the north as far south as Calabria and Peloponnisos. The species' reported vertical range is from sea level in the Balkans to the subalpine belt in the Alps. The presence of Dryomys nitedula in Europe can be traced back to the beginning of the Pleistocene, but its recent distributional area does not coincide with climatic factors, nor with the distribution of vegetation communities. Possible competition with Eliomys quercinus is discussed as a factor affecting the peripheral range distribution of Dryomys nitedula.
Skrjabingylus nasicola belongs to a genus of parasitic nematodes which invade members of the Mustelidae. Despite its widespread occurrence, little is known about the natural mechanisms of transmission. Certain inferences as to how transmission might occur are drawn from indirect sources, such as the behaviour of the nematode first stage larvae, and the severity of infections assessed by quantifying skull damage to the host species. The possibility that the parasite is transmitted in times of food shortage for the host is discussed in the light of previous work and knowledge of the ecology of mustelids.
Population dynamics and demography of the Wolf Canis lupus were studied in Bialowieza Primeval Forest (BPF, 1250 km²), the best preserved mixed and deciduous forest in the lowlands of Europe; 40% of BPF belongs to Poland and 60% to the Belarus Republic. Polish and Belarussian game departments' inventories of Wolf numbers (1946-93), archival hunting statistics (1847–1993), observations, snowtracking and reports on shot Wolves (1980-93) are presented. In BPF, Wolves coexist with five species of ungulates: European Bison Bison bonasus. Moose Alces alces, Red Deer Cervus elaphus, Roe Deer Capreolus capreolus and Wild Boar Sus scrofa.
Published records of cetaceans stranded on the Irish coast during the period 1901–95 are reviewed. In this review the number of stranding events has been used in the analysis and includes both live strandings and those animals washed up dead. There were 529 records involving 21 species. The Harbour Porpoise (27%) was the most frequently reported species, followed by Common Dolphins (16%) and Pilot Whales (15%). Minke Whales (8%) were the most frequently reported mysticete. The number of reported strandings has increased since the 1960s which is thought to be mainly due to increased observer effort. Cetaceans have stranded on all Irish coasts but mainly along the south coast and along the western seaboard but with no apparent overall seasonal trend. There was a peak in the strandings of Common Dolphins during 1991–92 when 27% (28 records) of all strandings were reported and of White-sided Dolphins when 60% (28 records) were reported, both of which were attributed to possible interactions with fisheries. The number of Striped Dolphins stranded on the Irish coast has increased steadily since the 1980s and may reflect increasing water temperatures.
These stranding records are considered inadequate to determine the status of most species of cetaceans in Irish waters but are sufficient to identify unusual stranding events such as high mortalities due to fisheries interactions or epizootics. More observer coverage is required before the stranding data are adequate for monitoring the status of most species but a stranding scheme is considered the most effective and efficient method of long-term monitoring of cetaceans in Irish waters.
Records of Cetacea stranded on the British coasts have been maintained in the British Museum (Natural History) since they were started in 1913. Investigations have now been made into the possibility of trends of developments in these strandings. The data have been arranged in groups appertaining to 5-year periods for all species combined, round the entire British coastline, also in relation to the coast on which the animals were stranded. For this purpose the coast of Great Britain has been divided into three separate areas. In addition, three species have been selected and treated separately to demonstrate the different trends.
The frequency of strandings appear to be correlated with the abundance of food fish, this in turn being related to the planktonic and nutritional values of the sea. There are one or two exceptions to this hypothesis, and it is suggested that there may be a correlation between an increase in strandings and a high mortality rate due to a lack of food fish.
The mammal fauna of Guinea is one of the least well-known in West Africa. This review has been prepared to bring together the scattered literature, and in the hope of stimulating research and identifying topics, geographical localities and habitats where knowledge is most limited. It covers some 411 biological publications, attempting to review all relevant material concerning terrestrial and freshwater aquatic mammals of Guinea published between 1946 and July 1996. Veterinary papers and those on domestic or introduced species have been excluded, as have those on Cetacea. Taxonomic literature is considered only insofar as it is relevant to biogeographical matters. The paper is divided into two parts: the first reviews information on the biology, ecology, natural history and biogeography of Guinea's mammals; the second part looks at threats, conservation measures and laws, and summarizes recommendations for future research. A preliminary check-list and a list of suggested priorities for future mammalogical research are provided.
ABSTRACT1. The Mammal Society was established in 1954 to link amateurs and professionals in promoting the study of mammals. It now directly assists British conservation science, and has fostered The British Deer Society, the National Federation of Badger Groups, The Bat Conservation Trust, the Ungulate Research Group and Sea Watch Foundation. The Society also has strong links with the Zoological Society of London, the Vincent Wildlife Trust and the People's Trust for Endangered Species/Mammals Trust UK, as well as with many other non-governmental organizations (NGOs) and statutory bodies.2. The Mammal Society provides fora for discussion, scientific symposia, mammal publications, and practical studies. It has also instigated major advances in the presentation of scientific knowledge through three editions of The Handbook of British Mammals under three successive editors: H.N. Southern, G.B. Corbet and S. Harris.3. From the 1970s the Society has highlighted conservation concerns (e.g. the decline of otters and persecution and management of badgers), informed legislation, supported many surveys, including harvest mice, pine marten, polecat, small rodents, hares, yellow-necked mice and foxes, and published authoritative species’ accounts, guides to methodology, Mammal Review, Notes/Communications from The Mammal Society, the annual Current Projects on British Mammals and other scientific and educational material.4. Country-wide mammal recording and training (Look Out for Mammals) developed in the 1990s alongside the Endangered British Mammals Fund. The ‘ground breaking’A Red Data Book for British Mammals, and A Review of British Mammals, both drew on Mammal Society expertise, helping to meet the UK Government's conservation responsibilities and emphasizing the growing influence of The Society. Co-operative monitoring has been developed with the British Trust for Ornithology through the Winter Mammal Monitoring scheme and is further projected with more than 20 NGOs and statutory bodies forming the ‘Tracking Mammals Partnership’.5. The Mammal Society now advises on UK Biodiversity Action Plans and plays a lead role in UK mammal conservation, highlighting problems and promoting solutions. However, many British mammals are still declining, many are neither legally protected nor subject to national conservation initiatives, and data are still lacking on the status of many terrestrial and most marine species. Much has been done, but there is still much to do.
The size of the Badger population in the Netherlands is estimated on the basis of sett surveys in 1960, 1970, 1980 and 1990. The numbers of used important setts were 588,640,405 and 606, respectively. So there were strong fluctuations especially due to the drop (-36%) in 1980. In 1990 the number of used important setts nearly returned to the level of 1960. However, there were important regional differences. There was a strong increase in areas with large woodlands, mainly in the central part of the country. In the south, with more traffic, farming and urbanization, the numbers remained 20–30% lower than in 1960, despite the fact that traditionally these were the best Badger areas. Only 25% of the important setts used in 1960 were still in use in 1990. The growth of the number of collapsed or lost setts increased considerably during those 30 years, indicating a rather large sett turnover probably due to disturbance or a related stress factor. Some possible causes of the fluctuations are discussed. It is recommended that a monitoring scheme be carried out every 2 or 3 years in some key areas, in order to get a better idea of the short-term fluctuation range of the population. For one-off, single-observation surveys, a simpler and more-robust sett classification is desirable, based on the number of intact holes, instead of on ‘main setts’.
Comparison of the results of a 1993–97 Barn Owl Tyto alba pellet survey with those of a similar survey from 1956–74 showed that Barn Owl diet had changed significantly. The primary differences were a widespread decrease in the percentage of Common Shrew Sorex araneus, combined with an increase in Pygmy Shrew Sorex minutus. The percentage of Wood and Yellow-necked mice Apodemus sylvaticus and A. flavicollis and Bank Vole Clethrionomys glareolus in the diet also increased. Changes in Barn Owl diet since 1974 were independent of land-class group, but were dependent upon region. This was due primarily to a large increase in the percentage of Apodemus spp. in Eastern England. Whilst the percentage of Pygmy Shrew in Barn Owl diet showed significant regional variation, there was no significant variation between land-class groups. The diversity of Barn Owl diet increased between 1974 and 1997, although it was still lower in 1997 than earlier in the century. This increase was dependent upon region, but independent of land-class group. The combined results of both surveys showed significant interland-class group variation in dietary diversity. Changes in diet are discussed in relation to the intensification of agriculture and other changes in land management since the 1970s. The effects on Barn Owls of these changes in prey abundance are discussed, particularly in relation to the decline in Barn Owl numbers during the twentieth century.
The dormouse survey was initiated by the Mammal Society and ran from January 1975 to April 1979. The dormouse is very much a southern mammal in Britain with a reduced range compared to that found 100 years ago. There seems to have been a decline in population and possible reasons for this are discussed. The habitat favoured by dormice is considered; a thick secondary layer is very important with bramble forming a major component. Dormouse nests are most often found in bramble at an average height of just over a metre from the ground. Dormouse requirements, particularly for scrub, should be considered when areas for wildlife conservation are being managed.
The Mammal Society has co-ordinated a population survey of Wood Mice Apodemus sylvaticus and Bank Voles Clethrionomys glareolus in 13 0.81 -hectare sites in Britain. Numbers of mice and voles live-trapped using standard methods were collated every May/June and November/December from 1982 to 1987. The data were analysed with results from four independent studies in England and the corresponding assessments of tree seed crop size. Wood Mouse numbers are usually higher in winter than in summer but Bank Vole fluctuations are less regular. In deciduous woodland, Wood Mouse mean relative densities are significantly greater in the winter and the following summer after a good seed crop than after a poor one; rates of population change from summer to winter are significantly higher when a good seed crop falls. Bank Vole relative densities are significantly greater in the summer following a good seed crop than after a poor one, and rates of change from winter to summer are significantly higher. In Wood Mouse populations, tests for density dependence suggest that it is strong from summer to winter but absent from winter to summer; in Bank Voles weaker density dependence is present in both halves of the year. Thus, Wood Mouse numbers are regulated in autumn but are also influenced by seed crop size in winter and the following summer; Bank Vole numbers are less strongly regulated during both autumn and spring and are influenced by seed crop size in the following summer. Evidence is presented suggesting that populations of each species in deciduous woodlands are synchronized over the country in summer and that Wood Mice are also synchronized in winter; highs and lows tend to coincide between different sites. The yield of tree seed is shown to vary significantly from year to year and may be the cause of the synchrony, but weather effects may also be involved.
The loss of ground by the Black Rat in the late 1950s continued through the next decade. Since then the number of site records has fluctuated and there has been less constancy in the places recording the presence of the rat. This impermanence of populations together with their small size suggests that introductions are short lived and that the species has only a tenuous foothold in the United Kingdom today. Port records show that rats are still arriving regularly by ship and it is suggested that future developments in climate and trade might further assist entry and make the environment more favourable for the Black Rat.
This is a report based on the public participation exercise known as the 'Great Nut Hunt', launched in 1993 and running until October 1994. Opened hazel Corylus avellan nuts were invited to be sent in for confirmation as having been opened by dormice or not, from which a map of sites for evidence of dormouse presence was drawn up. This is presented together with a map and table of sites checked and whether yielding evidence of dormouse presence. Distribution of dormouse confirms earlier studies, occurrence being restricted to S and SW England, with some sites in Wales and one site in Cumbria. Local extinction in some northern counties, eg Yorkshire, is also confirmed.
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.
ABSTRACT • This review highlights the status of the European wild rabbit Oryctolagus cuniculus, which is threatened within its native range and yet is a highly successful colonizer across its worldwide, introduced range. • The European wild rabbit is a keystone species in Iberia, and the survival of a range of threatened predator species, including the Iberian lynx Lynx pardinus and Spanish imperial eagle Aquila aldabertii, is dependent upon the restoration of rabbit populations. Although not native to the UK, the rabbit also performs significant ecosystem services for nationally rare UK species, by maintaining short sward heights in heathland and grassland ecosystems, and serving as a prey item for populations of predators. • We identify the European wild rabbit as an excellent model to demonstrate the wide range of complex effects that an introduced mammalian species may exert on ecosystems to which it has been introduced. These effects include habitat degradation following overgrazing, competition with native mammals and facilitating meso-predator release and hyperpredation. • We also show that rabbit eradication from some sites may generate more problems than are solved because of the impacts of trophic cascades stemming from dependence on rabbits by native predator assemblages.
The aardvark is a large nocturnal mammal with an anatomy highly specialized to cope with a myrmecophagous diet and a fossorial habit. Today it is present throughout Africa south of the Sahara, but the actual distribution is very patchy and in some areas it has been largely exterminated by man.
For many years the species was classified in the Edentata, along with other ‘anteaters’ such as Myrmecophaga and the pangolins. It is now recognized as comprising an order to itself, the Tubulidentata; so named because of the unique structure of the teeth.
Aardvark are generally believed to have evolved from the protoungulates (Condylarthra), although earlier origins for the group have been suggested.
Little is known of the ecology of this animal, no detailed study having been made. Burrows, often quite extensive, are dug and play an important role in the life of aardvark. They are the diurnal resting sites, refuges from nocturnal predators and the places where young are born.
Termites, particularly Macrotermes, and ants (Formicidae) constitute almost the whole diet, being obtained by frequent digging at night. A zig-zag foraging pattern is used with no particular attention being paid to termite mounds. The senses of hearing and smell both appear to be important in food location.
The extent of man's effects on the animal, through hunting and habitat alteration, is not known. It is concluded that a detailed ecological study is required to assess the need for conservation measures and generally gauge the status of the species.
The International Whaling Commission (IWC) recognizes aboriginal subsistence whaling to be distinct from commercial whaling, and these two broad categories of whaling are subject to different management approaches. This paper describes recent, ongoing and likely future whale hunts that qualify, or may qualify, for aboriginal subsistence status within the IWC’s management framework. To ensure conservation of the whale populations, a forthright exposition of the origins, development and character of these hunts is needed in addition to stock assessment, a risk-averse catch limit algorithm and appropriate mechanisms within the whaling communities to ensure compliance. The hunts for Bowhead Whales (Balaena mysticetus) and Gray Whales (Eschrichtius robustus) in the Arctic and North Pacific, respectively, and Sperm Whales (Physeter macrocephalus) in Indonesia have long histories and local origins. Those for Humpback Whales (Megaptera novaeangliae) in the Lesser Antilles and at Tonga in the South Pacific were introduced by foreign commercial whalers. Whale hunting in the Philippines appears to have originated both locally and as a result of foreign influence. The relatively recent initiation of whaling for Fin Whales (Balaenoptera physalus) and Minke Whales (Balaenoptera acutorostrata) in Greenland required introduced technology but can be viewed as a modern adaptation of an ancient tradition. Consensus in deciding how to classify and manage non-industrial whaling has been, and will remain, elusive. Even with common definitions of key terms such as ‘subsistence’, ‘commercial’ and ‘aboriginal’, interpretations will depend on whether one’s priorities are whale-centred or human-centred.
At high densities, deer populations may have adverse effects upon and within their environment. In this review we explore published and unpublished information to derive density thresholds for deer species in relation to impacts upon agriculture, forestry, conservation habitats, road traffic, and human and livestock health in the UK. Impact levels are affected by many factors other than absolute density. We therefore seek to establish the range of densities within which negative impacts might start to occur and which should trigger objective monitoring of actual impacts.
In commercial forestry, a threshold of 4 deer per 100ha has been suggested. Unfenced native woodlands seem to regenerate naturally if there are fewer than 4–5 large deer or fewer than 25 roe deer Capreolus capreolus per 100ha; open habitats may suffer only light or moderate impacts from red deer Cervus elaphus at landscape densities of 7–8 per 100ha.
Woodland bird species may have declined where deer densities are high but absolute thresholds seem impossible to establish. One study suggests maximum diversity at about 8 white-tailed deer Odocoileus virginianus per 100ha.
Deer–vehicle collisions are affected by various factors in addition to deer density, but British and American studies suggest that accident frequencies decline at densities below 7–8 per 100ha.
Fallow deer Dama dama populations may maintain bovine TB (bTB) infection at much lower densities (25/100ha) than red or roe deer (91/100ha and 200/100ha, respectively) assuming 100% prevalence. Even at 30% prevalence a density of 75 fallow deer per 100ha could maintain bTB within the population.
We conclude that deer density alone is unlikely to be a good predictor of impact, and suggest that long-term management should be based on assessment both of actual impacts and apparent density of deer.
This is a literature review of the relationship between the abundance of tree seeds and the productivity, survival and dispersal of Holarctic tree squirrels. Causal links between changes in tree seed supplies and changes in squirrel numbers are often masked by various factors including intraspecifk and interspecific competition for seed, weather, predation and seed hoarding; density-dependent relationships have not been clearly established. Tamiasciurus and Sciurus species have different seed-hoarding strategies which are associated with differences in their social and spatial organization. Average squirrel densities in the long-term are discussed in relation to forest habitat type, and directions for future research indicated.
Over the last few decades, there have been significant declines in Brown Hare Lepus europaeus numbers throughout Europe, leading to concern for their status in many countries. In Britain, there were no quantified data on the extent of this decline, on current population levels, or any baseline against which to monitor future population changes. The need for a quantified national hare survey led to this evaluation of the techniques available to assess hare numbers. Published information on counting hares is reviewed, and various techniques compared by applying them to a number of sites in southern England.
1Accurate and sensitive survey and monitoring methods are needed for shrews. We present a new design of hair tube and a new, simple method of species identification from multivariate analysis of four parameters measured from shrew guard hairs using a binocular microscope with incident light.2Multivariate analysis of these parameters measured from hairs of known identity showed that they can be used to identify hair to the species level with 85% accuracy.3We compared our indices of abundance from hair tubes (the hair tube index) with those from live trapping in 40 field margins. Capture-mark-recapture methods showed that capture rate did not vary systematically across sites, so that number of individuals captured was used as an index of abundance.4The hair tube index showed a significant association with the number of individuals captured for Sorex araneus and Neomys fodiens. The lack of a significant association for Sorex minutus may be because hair tubes are more sensitive in detecting this species than live trapping.5Hair tubes have additional advantages over live trapping, since they do not require frequent checking, are much lighter and cheaper than live traps, and no licence is required for their use in the UK. We therefore recommend consideration of their use in future surveys and monitoring studies of shrews. We provide an equation so that other researchers can use our multivariate method.
The Northern Ireland Hare Survey documented the distribution of the Irish Hare (Lepus timidus hibernicus). Historical game bag records and other, more contemporary, records of hare distribution were examined. These data indicate how numbers of L. t. hibernicus may have changed over the last 140 years. The results of the Northern Ireland Hare Survey suggested that L. t. hibernicus was widespread throughout Northern Ireland. Current average densities are no more than 0.65 hares/km2. Game bag records indicate that hare densities may have been much higher in the past, with a maximum of 138 hares/km2 recorded on Crom Estate, Co. Fermanagh, in 1864. Evidence from hare distribution recorded during the Northern Ireland Rabbit Survey indicates that hare numbers declined between 1984 and 1994. Evidence from all sources suggests that L. t. hibernicus has declined in abundance substantially, with present total population estimates for Northern Ireland ranging from 8250 to 21 000 individuals. Flushing data indicate that rushes and hedgerows are important diurnal resting areas for hares. While the principal reason for the decline in numbers of L. t. hibernicus in Northern Ireland is not clear, more species-rich pasture and provision of areas of cover, such as rushes, may arrest further declines, or indeed promote numbers of hares, particularly in lowland areas.
ABSTRACT • Managing the conservation impacts of deer requires knowledge of their numbers. However, estimating densities in forested areas is problematic, with pellet-group-based methods subject to error and uncertainty in estimating defecation and decay rates in addition to sampling variance. Use of thermal imaging equipment allows direct census by distance sampling. • Densities of introduced Chinese muntjac Muntiacus reevesi and native roe deer Capreolus capreolus were estimated in 12.8 km2 of conifer forest in eastern England by thermal imaging distance transects. Estimated density of introduced muntjac (±95% confidence intervals [CI]: 20 ± 8 km−2) exceeded that of native roe deer (16 ± 6 km−2); 95% CI of c. 40% were achieved in 10 days of fieldwork. • Density estimates were not sensitive to the number of width bands applied during analysis. Detectability functions differed, with narrower effective strip widths (ESW) for muntjac (74 m) than roe deer (123 m). Thus, it is important to discriminate between species when censusing mixed assemblages. Detectability and ESW also differed among plantation growth stages. Stratification by habitat may therefore improve accuracy of density estimates but would require additional survey effort.
ABSTRACT The creation of grassy field margins, as part of the UK Government's Environmental Stewardship (ES) scheme, is one of a number of measures proposed to mitigate the adverse effects of arable intensification on wildlife. Widespread development of these margins will potentially increase the amount of habitat available to small mammals in arable landscapes, as many species do not inhabit the cropped area. The aim of this study was to determine what impact ES-type margins might have on small mammals. We compared small mammal abundance and biomass in spring and autumn on 3-m-wide and 6-m-wide grassy margins with that on conventionally managed field edges that have no margin (0 m wide) and are intensively cultivated to the field edge. Bank voles Clethrionomys glareolus, wood mice Apodemus sylvaticus and common shrews Sorex araneus were the most abundant species; few field voles Microtus agrestis were captured on any margin. In autumn, bank vole and common shrew numbers were higher on the grassy margins than on conventional field edges, and margin width per se was positively associated with bank vole abundance. The number of wood mice captured did not differ among the different margin types. Total small mammal biomass increased between spring and autumn on the 3-m- and 6-m-wide grassy margins, but decreased on the 0-m-wide margins. Total biomass in autumn was three times higher on 6-m-wide margins compared with the conventional arable field edges.
Insectivorous bats are integral components of terrestrial ecosystems. Despite this, a growing number of factors causing world-wide declines in bat populations have been identified. Relatively abundant species are important for bat conservation because of their role in ecosystems and the research opportunities they offer. In addition, species that have been well-studied present unique opportunities to synthesize information and highlight important areas of focus for conservation and research. This paper focuses on a well-studied abundant bat, Eptesicus fuscus. I review the relevant literature on habitat use, diet and roost selection by E. fuscus in North America, and highlight important areas of conservation and research for this species, including the effects of roost disturbance, control of economically important insect pests, exposure to pesticides, long-term monitoring of populations, and the potential consequences of expanding populations. These issues have broad implications for other species and can be used to focus future research and conservation efforts.
The origins, early history, captive populations, spread and habitat preferences of Reeves' Muntjac in Britain are reviewed. It is suggested that much of the published information on the history of Muntjac in Britain is based on misconceptions, and that each subsequent report has continued to promulgate a false impression on the origins, time-scale and pattern of spread of the species in Britain. Indian and Reeves' Muntjac were introduced to Woburn Park in Bedfordshire within a year of each other, and it appears that the Indian Muntjac did not thrive, at least in the decade following their introduction. How long they survived as a free-living species in Britain is unclear, but it was probably only a few years. However, there is some evidence to suggest that they might have persisted within the Park at Woburn until 1930.
The seasonal or cyclical changes in the size, histology and secretions of the male reproductive organs and accessory glands of certain mammals are reviewed briefly. Some mammals such as man and the laboratory rat are fertile throughout the year whereas others such as the Red deer stag and the mole are fertile only at certain periods. The male's cycle cannot necessarily be inferred from the female's cycle in those mammals that have a seasonal cycle, neither can it be inferred from rutting or copulatory behaviour. In some species the male is fecund throughout the year whereas the female has a well defined breeding season or seasons, which is defined as the period between conception and parturition. It is stressed that morphological changes, whether macroscopic or histological, do not necessarily reflect the secretory activity of the gland and that the presence of spermatozoa indicates fecundity, not fertility.
1. A field experiment was used to test the effectiveness of a synthesized bat call as an acoustic lure to attract bats into mist nets in woodlands in southeast England. The stimulus was modelled on a social call of the rare Bechstein's bat Myotis bechsteinii.
2. In the Test condition, when the synthesized call was played, 23 bats of four species were captured, including six Bechstein's bats. In the Control condition, when no calls were played, only one bat was caught.
3. The bat call synthesizer is an effective tool for increasing capture rates for bats. Used as part of a systematic survey programme, it has the potential to provide the first baseline data on the distribution of bats in British woodlands.
ABSTRACT • The literature on bark-stripping by red deer Cervus elaphus in Europe is reviewed to reveal quantitative variation in this behaviour and relate it to deer density and local characteristics such as dominant tree species, occurrence of artificial feeding, altitude, region and size of the study site. We also review the importance of bark in red deer diets over the seasons and discuss the causes of bark-stripping, focusing on the significance of bark as food. • Over the 36 sites examined, the rate of bark-stripping was highly variable (from 0 to 84% of susceptible trees debarked), with less damage in Scotland than in other European sites for which bark-stripping rates were higher at high red deer density. Altitude, the size of the study site, the number of dominant tree species and the occurrence of artificial feeding do not significantly relate to the rate of bark-stripping. • Bark sometimes made up a large proportion of red deer diet (> 10%), especially in areas with severe winters (high levels of snow), whereas in study sites with mild winters, bark was practically not eaten at all. • These results suggest that severe bark-stripping could be related to a reduction in food resource availability. This food availability hypothesis needs to be better documented, dealing particularly with the possible interaction between food availability and red deer density.
The generally accepted idea that the house mouse is a single, world-wide species which owes its success largely to commensalism with man is wrong. There are at least five European and two Asian species lumped together under the name Mus musculus, plus another fourteen Asian species in the same genus. The house mouse of western Europe is the one that has been introduced to the Americas and Australasia, as well as being domesticated in the laboratory and ‘fancy’ strains; it is properly described as Mus domesticus. A complication of this particular species is the existence of chromosomal races involving the fusion of pairs of chromosomes, apparently at random. These races seem to be reproductively isolated from normal (2n = 40) mice. They have been described in southern Europe and northern Britain.
The family Soricidae is reviewed with special regard to anatomical structures related to habitat and life-style. Some 266 species in 20 genera are classified into six feeding and foraging categories: terrestrial, semifossorial, scansorial, semiaquatic, psammophilic and anthropophilic. Examples of corresponding anatomical adaptations are given as well as notes on adaptive radiation and convergent evolution.
In the last 8 years, examples of prolonged sperm storage, delayed implantation and retarded embryonic development have been reported from some South temperate Old World Microchiroptera. It is suggested that in the species concerned, hibernation or prolonged periods of hypothermia restrict all reproductive processes to the summer months (September to April) and that this 8-month period is too short to accommodate a ‘typical’ microchiropteran reproductive cycle. Consequently some form of reproductive adaptation, in which a period of delay occurs in the reproductive cycle, is one requirement for hibernating bats in subtropical and temperate latitudes. The inclusion of a period of reproductive delay during winter effectively lengthens the reproductive cycle and allows gametogenesis to be initiated in the middle of one summer, and parturition to occur early the following summer. It is suggested that the type of reproductive delay evolved by a species may be related to its pattern of winter activity.
It is suggested that in the hibernating members of the Vespertilionidae and Rhinolophidae the typical tropical reproductive strategy of seasonal monoestry has been modified by the inclusion of a period of reproductive delay. The principal effect of this is to lengthen die reproductive cycle so that gametogenesis is initiated in the middle of one summer, and parturition and lactation occur during the following summer, when food is abundant. The diree reproductive delay phenomena recorded in Microchiroptera from Soudi Africa should be regarded as different ways of lengthening the reproductive cycle, possibly determined by the winter activity of the species. Although these ideas are based on observations of the reproduction of African bats, they can equally be used to explain die evolution of reproductive delays in north temperate bats.
Small, scattered, but resident, populations of Golden Jackal Canis aureus occur along the coasts of the Balkan Peninsula. The bulk of these European Jackals is concentrated in the eastern parts of the Peninsula, mainly in Bulgaria. The northern border of the resident population lies along the Danube in the Walachian Plain of Romania, and in Srem (Yugoslavia). Vagrants may appear far outside the Balkans in north-eastern Italy, Slovenia, Austria, Hungary and Slovakia. Whilst the species is in decline in Greece, it has expanded its area in Bulgaria from = 2400 km2 in 1962 to 80 000 km2 in 1985, i.e. a 33-fold range increase within 23 years.
ABSTRACT • Trade-off theory has been extensively used to further our understanding of animal behaviour. In mammalian herbivores, it has been used to advance our understanding of their reproductive, parental care and foraging strategies. Here, we detail how trade-off theory can be applied to herbivore–parasite interactions, especially in foraging environments. • Foraging is a common mode of uptake of parasites that represent the most pervasive challenge to mammalian fitness and survival. Hosts are hypothesized to alter their foraging behaviour in the presence of parasites in three ways: (i) hosts avoid foraging in areas that are contaminated with parasites; (ii) hosts select diets that increase their resistance and resilience to parasites; and (iii) hosts select for foods with direct anti-parasitic properties (self-medication). We concentrate on the mammalian herbivore literature to detail the recent advances made using trade-off frameworks to understand the mechanisms behind host–parasite interactions in relation to these three hypotheses. • In natural systems, animals often face complex foraging decisions including nutrient intake vs. predation risk, nutrient intake vs. sheltering and nutrient intake vs. parasite risk trade-offs. A trade-off framework is detailed that can be used to interpret mammal behaviour in complex environments, and may be used to advance the self-medication hypothesis. • The use of trade-off theory has advanced our understanding of the contact process between grazing mammalian hosts and their parasites transmitted via the faecal–oral route. Experimental manipulation of the costs and benefits of a nutrient intake vs. parasite risk trade-off has shown that environmental conditions (forage quality and quantity) and the physiological state (parasitic and immune status) of a mammalian host can both affect the behavioural decisions of foraging animals. • Naturally occurring trade-offs and the potential to manipulate their costs and benefits enables us to identify the abilities and behavioural rules used by mammals when making decisions in complex environments and thus predict animal behaviour.
ABSTRACT • Morphometrics, the study of the variation and change in form amongst organisms, serves as a basic methodological tool in various fields of biological research, including systematics. Because it includes information about spatial relationships amongst anatomical landmarks, geometric morphometrics is more suitable for analyzing morphometric variation than methods based on distance measurements. • Geometric morphometrics allows us to answer general ecological and evolutionary questions about shape. • In this paper, landmark-based methods are described and illustrated, based on a dataset of measurements from 295 Apodemus mandibles, and the applications of such methods in the systematics of insectivores (Eulipotyphla) and rodents (Rodentia) are summarized.
ABSTRACT • Adaptive adjustments in offspring sex ratios in mammals have long been reported, but the conditions and mechanisms that prompt shifts in the proportion of sons and daughters born are still unclear. • Empirical evidence indicates that offspring sex in mammals can be related to a diversity of environmental and maternal traits. However, the underlying assumptions regarding offspring and maternal fitness are rarely tested. • Physiological mechanisms of maternal selection of offspring sex may occur at many stages during the prolonged maternal investment stage, and a pluralistic approach to studying mechanisms might prove fruitful. • This review highlights the apparent frequency, in marsupial mammals, of sex ratio bias, which has largely been recorded as conforming to one of a few hypotheses. • Marsupials are ideally suited to experiments involving cross-fostering of offspring, which can allow rigorous tests of the fitness consequences of rearing one sex vs. the other. The reproductive biology of marsupials lends the group to detailed studies of the timing and physiological correlates of offspring sex biases. • Many components of metatherian biology may prove advantageous in experimental studies of sex allocation in mammals, and together may provide a prosperous avenue for examining adaptive and mechanistic hypotheses in mammalian sex allocation.
1. While the effect on animals of handling them and fitting them with radio tags has been investigated, little work has been reported testing the effect of the presence of a human observer tracking an animal.
2. The activity of wood mice fitted with radio collars and confined to a semifield pen was measured in the presence and the absence of a human observer. Free-ranging wood mice were radio tracked by using two protocols: ‘fixes’ taken periodically, and periods of continuous tracking.
3. There was no significant difference in any quantified aspect of the animals’ behaviour. This suggests that the presence of a human tracker has a negligible effect on the behaviour of wood mice.
We investigated the distribution of a range of small mammal species in five urban habitats in north-west Bristol: residential gardens, woodlands, allotment gardens, scrub and a cemetery. Wood mouse Apodemus sylvaticus abundance in residential gardens was negatively related to the abundance of cats and the distance to the nearest patch of natural or seminatural vegetation. These results suggest that urban small mammal populations may be limited by predation and habitat fragmentation, although the effects of the latter may be offset by the availability of good quality gardens.