Rosie Woodroffe

Positive and negative effects of widespread badger culling on tuberculosis in cattle.

Human and livestock diseases can be difficult to control where infection persists in wildlife populations. For three decades, European badgers (Meles meles) have been culled by the British government in a series of attempts to limit the spread of Mycobacterium bovis, the causative agent of bovine tuberculosis (TB), to cattle. Despite these efforts, the incidence of TB in cattle has risen consistently, re-emerging as a primary concern for Britains cattle industry. Recently, badger culling has attracted controversy because experimental studies have reached contrasting conclusions (albeit using different protocols), with culled areas showing either markedly reduced or increased incidence of TB in cattle. This has confused attempts to develop a science-based management policy. Here we use data from a large-scale, randomized field experiment to help resolve these apparent differences. We show that, as carried out in this experiment, culling reduces cattle TB incidence in the areas that are culled, but increases incidence in adjoining areas. These findings are biologically consistent with previous studies but will present challenges for policy development.

Impact of localized badger culling on tuberculosis incidence in British cattle

Pathogens that are transmitted between wildlife, livestock and humans present major challenges for the protection of human and animal health, the economic sustainability of agriculture, and the conservation of wildlife. Mycobacterium bovis, the aetiological agent of bovine tuberculosis (TB), is one such pathogen. The incidence of TB in cattle has increased substantially in parts of Great Britain in the past two decades, adversely affecting the livelihoods of cattle farmers and potentially increasing the risks of human exposure. The control of bovine TB in Great Britain is complicated by the involvement of wildlife, particularly badgers (Meles meles), which appear to sustain endemic infection and can transmit TB to cattle. Between 1975 and 1997 over 20,000 badgers were culled as part of British TB control policy, generating conflict between conservation and farming interest groups. Here we present results from a large-scale field trial that indicate that localized badger culling not only fails to control but also seems to increase TB incidence in cattle.

Lethal control of African lions (Panthera leo): local and regional population impacts

Large carnivores have declined worldwide, largely through conflict with people. Here, we quantify the impact of lethal control, associated with livestock depredation, on a population of African lions (Panthera leo )l iving outside protected areas. Farmers shot lions only in response to livestock attacks. Nevertheless, adult mortality was high and a simple model predicted that the population was marginally stable or slowly declining. Mortality was four times higher among lions radio-collared in association with attacks on livestock, than among lions with no known history of stock killing, suggesting that some animals were habitual stock killers. Known stock killers also experienced lower reproductive success; hence there was strong artificial selection against stockkilling behaviour. In addition, mortality was higher among lions whose home ranges overlapped a property where non-traditional livestock husbandry was associated with chronic depredation by lions. This 180 km 2 ranch acted as a sink that directly affected lions over more than 2000 km 2 and may have undermined the viability of the study population. Our results suggest that sustainable coexistence of lions and people demands livestock husbandry that effectively deters predators from acquiring stock-killing behaviour, but that lethal control may play an important role in avoiding the spread of such behaviours through the population.

Wildlife viewing preferences of visitors to protected areas in South Africa: implications for the role of ecotourism in conservation.

Ecotourism has a potentially vital role to play in conservation by generating economic incentives for nature conservation. However, some authors contend that this potential may be limited by narrow viewing preferences among visitors to protected areas, suggesting that most tourists are primarily interested in seeing charismatic mega-fauna largely confined to government or privately-owned parks. We assessed viewing preferences among tourists at four protected areas in South Africa to test the validity of this contention. Mega-herbivores and large carnivores were the most popular species, particularly among first-time and overseas visitors, but African visitors and experienced wildlife viewers were more interested in bird and plant diversity, scenery, and rarer, less easily-observed and/or less high-profile mammals. Several of these favored species are extinction prone and often absent from wildlife areas due to sensitivity to human encroachment and competition with more abundant species. Hence, ecotourism may provide incentives for the conservation of intact guilds, and management for ecotourism may align more closely with biodiversity conservation objectives than suggested by critics. This potential could be enhanced by diversification of tour operator advertising to feature aspects of biodiversity other than the ‘big five’. Nonetheless, charismatic mega-fauna have a vital flagship role by attracting most overseas and first-time visitors to protected areas.

Culling and cattle controls influence tuberculosis risk for badgers

Human and livestock diseases can be difficult to control where infection persists in wildlife populations. In Britain, European badgers (Meles meles) are implicated in transmitting Mycobacterium bovis, the causative agent of bovine tuberculosis (TB), to cattle. Badger culling has therefore been a component of British TB control policy for many years. However, large-scale field trials have recently shown that badger culling has the capacity to cause both increases and decreases in cattle TB incidence. Here, we show that repeated badger culling in the same area is associated with increasing prevalence of M. bovis infection in badgers, especially where landscape features allow badgers from neighboring land to recolonize culled areas. This impact on prevalence in badgers might reduce the beneficial effects of culling on cattle TB incidence, and could contribute to the detrimental effects that have been observed. Additionally, we show that suspension of cattle TB controls during a nationwide epidemic of foot and mouth disease, which substantially delayed removal of TB-affected cattle, was associated with a widespread increase in the prevalence of M. bovis infection in badgers. This pattern suggests that infection may be transmitted from cattle to badgers, as well as vice versa. Clearly, disease control measures aimed at either host species may have unintended consequences for transmission, both within and between species. Our findings highlight the need for policymakers to consider multiple transmission routes when managing multihost pathogens.

Livestock husbandry as a tool for carnivore conservation in Africa’s community rangelands: a case–control study

Conflict between people and wildlife is a major issue in both wildlife conservation and rural development. In African rangelands, species such as African wild dogs (Lycaon pictus), cheetahs (Acinonyx jubatus), lions (Panthera leo), leopards (Panthera pardus), and spotted hyaenas (Crocuta crocuta) may kill livestock and are therefore themselves killed by local pastoralists. Such conflict has led to the extirpation of these species from many areas, and also impacts the livelihoods of local livestock farmers. To investigate the possibilities for coexistence of people, livestock, and large predators in community rangelands, we measured the effectiveness of traditional livestock husbandry in reducing depredation by wild carnivores, using a case–control approach. Different measures were effective against different predator species but, overall, the risk of predator attack by day was lowest for small herds, accompanied by herd dogs as well as human herders, grazing in open habitat. By night, the risk of attack was lowest for herds held in enclosures (‘bomas’) with dense walls, pierced by few gates, where both men and domestic dogs were present. Unexpectedly, the presence of scarecrows increased the risks of attack on bomas. Our findings suggest that improvements to livestock husbandry can contribute to the conservation and recovery of large carnivores in community rangelands, although other measures such as prey conservation and control of domestic dog diseases are also likely to be necessary for some species.

Mother's little helpers: Patterns of male care in mammals

Over the past 20 years, long-term studies have shown that mammalian fathers, brothers and even unrelated males may contribute substantially to the care of the young. Recently, more field studies of mammals with male care have further expanded interest in male care potential. Male mammals can never be sole care-givers because offspring depend on maternal milk, but assistance provided by males may allow females to produce more energetically costly litters. The need for such male care contributes to the development of obligate social monogamy or communal breeding.

Habitat, food availability and group territoriality in the European badger, Meles meles

Since European badgers (Meles meles L.) form non-cooperative groups in parts of their geographic range, but are solitary elsewhere, their social systems have been at the centre of a debate about the evolution of group living in the Carnivora. In a recent review of models of non-cooperative sociality, Woodroffe and Macdonald (1993) presented evidence in favour of two hypotheses, which suggested that badger groups might form because either the distribution of blocks of foodrich habitat, or the economics of excavating new setts, prevented the division of group territories into individual territories. We present data upon the response of badger spatial organisation to a reduction in food-patch dispersion, brought about by the conversion of carthwormpoor arable land to earthworm-rich pasture over a 15-year period. This change in the distribution of earthworm-rich habitats was accompanied by territory fission, facilitated by the excavation of new setts. This indicates that the availability of sett sites had not constrained territory size at the start of the study. However, sett distribution did define the size and configuration of the daughter territories. We also show that variation among territories in the availability of food-rich habitats was reflected in the reproductive rates and body weights of the groups that inhabited them, although there was no detectable effect upon group size.

Female/Female Competition in European Badgers Meles meles: Effects on Breeding Success

We present data on the effects of female/female competition on the reproductive success of European badgers Meles meles in Britain. While a single, dominant female usually suppresses reproduction in other female group members, elsewhere up to four females may breed successfully in each group. Across Britain, the mean number of breeding females per social group decreases in populations living at high latitudes, where food availability and population density are relatively low. Within our study population in southern England, the number of breeding females in each social group increased with the quality of the group territory. In our study population, all females aged 3 years and older became pregnant, but a proportion of females lost their litters during gestation or around the time of birth. The proportion of females that lost their litters was higher in larger groups. However, mean litter size at weaning remained roughly constant despite variation in the number of females lactating, and preweaning cub mortality appeared to be low. Females tended to disperse away from very large groups, and may have increased their chances of breeding in this way. These results suggest that females competed for breeding status, but that there was little competition among females thereafter. The characteristics of females that produced cubs successfully differed between the 2 years when this study was carried out. Only females in relatively good condition bred successfully following a very dry summer, when food availability was low. However, when food availability was high, following a wet summer, females were in better condition on average and breeding success appeared to be related to social status. We suggest that this reflected a difference in the structure of competition between the two years. In contrast with the situation in other social carnivores, reproductive suppression in badgers appears to be a response to female/female competition for resources, rather than a need for co-operative care of the young. Although alloparental care occurred in at least one badger population, this population had the lowest, rather than the highest, level of reproductive suppression.

Determinants of attitudes towards predators in central Kenya and suggestions for increasing tolerance in livestock dominated landscapes

Where people and livestock live with predators there is often conflict that can lead to lethal control of predators. We evaluated attitudes of local people towards large predators and developed a novel index of tolerance by quantifying the number of livestock respondents would be willing to lose before killing the predator responsible. We interviewed 416 subsistence livestock farmers (community members) and commercial livestock ranchers in central Kenya. Commercial ranchers had more positive attitudes and higher tolerance than community members. Community members said their tolerance would increase if they were to derive income from ecotourism or trophy hunting. We found that community members with land title deeds were most tolerant of predators, stressing the importance of land security for conserva- tion efforts. Subsistence livestock farming is the primary land use throughout much of Africa and, as a result, identifying strategies to improve tolerance of predators under this land tenure system is of major conservation significance.