710 Mammals, Conservation Efforts for anthropogenic factors For example, carnivores with large home ranges frequently travel beyond the borders of protected areas, where they come into contact with people Such contact is often fatal, with the result that wide-ranging species require larger parks and reserves for effective protection (Woodroffe and Ginsberg, 1998) The direct and indirect effects of human activity on mammals lead to general associations between high human population density and local extinction of mammal populations Elephants, primates, and carnivores all demonstrate such associations This probably reflects complex interactions between direct killing of mammals by people, destruction of mammals’ habitat by people, or, on the small scale, simple avoidance of people by mammals Price and Gittleman (2007) showed that artiodactyls (even-toed ungulates) are more likely to be threatened if they live in areas of high poverty, and that if a species is also hunted, then slowergrowing species are more likely to be threatened The effect of living in poor areas is probably related to the degree of human use of wildlife habitat and habitat clearance that is going on, whereas the effect of the species’ biology is probably because slow-growing species are less resilient to high levels of hunting In summary, individual species may be threatened by a number of different factors, so that the type of conservation effort needed to counteract these threats can also vary widely between species However, it is possible to discern some broad patterns that can help to identify species that may be at particular risk of extinction These patterns relate both to the biology of the species and to the level and type of human pressure on the species and its habitat Types of Conservation Effort The threats described above demand a variety of conservation measures We discuss these measures briefly, giving more detailed evaluations of their costs and benefits in the case studies Legal protection of areas is the most traditional form of conservation; this approach, if effectively enforced, has the advantage of protecting habitats, as well as particular species, against a multitude of threats associated with human activities While reserves are often targeted at a particular species, and even named as such (e.g., Addo Elephant Park, Gemsbok National Park), well-planned reserves can protect multiple species, habitats, and landscapes Large mammals are often used as ‘‘flagships’’ to promote such reserves (e.g., India’s Project Tiger) Craigie et al (2010) analyzed mammal population trends in African protected areas over the period 1970–2005, and showed an average 59% decline in species’ population sizes within protected areas, which suggests that overall, protected areas are not enough to conserve Africa’s mammal populations However, they uncovered major regional differences; in southern Africa populations were generally stable, while severe declines were recorded in West Africa This suggests that a better understanding of what makes protected areas successful in some areas and not in others could markedly improve conservation effectiveness Legal protection of species or populations may also be used as a conservation measure For example, stringent legislation in the United Kingdom protects the European badger from killing and disturbance International treaties have effectively protected many cetacean species from intense overhunting, and led to population increases in previously highly threatened species such as the bowhead whale (George et al., 2004) Difficulties of enforcement mean that such legislation may have limited value as a conservation tool in countries without effective governance, however; for example, a wide range of mammals is still openly traded for meat in the Democratic Republic of Congo despite having full legal protection (Rowcliffe et al., 2004) Species threatened by exploitation may be protected by legislation governing trade rather than preventing killing For example, it is not illegal to kill leopards in some countries, such as the Gambia, but international trade in their skins is prohibited from or to member countries of the Convention on International Trade in Endangered Species (CITES) Problems surrounding the enforcement – and ethics – of legislation prohibiting the exploitation of wild populations or use of protected areas have led to initiatives aimed at conservation through sustainable use The rationale behind such initiatives is that sustainable use should ensure that local people value and protect natural resources, if the benefits accrue to local communities Like the establishment of reserves, this approach has attracted controversy; the array of political, legislative, and logistical concerns that it entails is different from, but no less complex than, that surrounding more traditional legal protection At the international level, sustainable use and equitable sharing of the benefits from biodiversity are at the heart of the Convention on Biological Diversity Threatened populations may also be protected through direct management, particularly when the population has become very small and unlikely to survive in the wild without intervention Habitat management involves measures such as provision of waterholes or den sites, or control of predators (both native and invasive) Population management describes a variety of interventions such as vaccination against infectious diseases and supplementation from other populations, wild or captive Species conservation may also involve reestablishment of extinct populations through reintroduction of captive-bred or wild-caught mammals Such measures have been important in the recovery of some endangered species (e.g., golden lion tamarins and red wolves), as well as for the reestablishment of populations of species that remain widespread but have suffered local extinctions (e.g., gray wolves) Finally, the conservation of some endangered species may benefit from captive breeding, maintaining a population in captivity that may or may not be intended for release into the wild Such efforts have proven valuable for critically endangered species reduced to their last few individuals (e.g., Arabian oryx, black-footed ferret, and island fox), in which managed breeding can minimize the loss of genetic variation However, captive breeding is a choice of last resort, as it can lead to the loss of wild behaviors Animals that are habituated to people are particularly vulnerable to persecution or exploitation once reintroduced Przewalski’s horse, however, provides an example to show that all is not lost when species are reduced just to a few individuals in captivity In this case, the individuals were not even genetically pure, with their genepool having been contaminated by domestic horses