by the removal of adult males from their populations. Males are trophy hunted more frequently than females. However, the removal of these males still degrades the networks and groups these species create in order to survive and provide for offspring. Hunting regulations and laws proposing constant proportions or thresholds of community members for these species have been proposed in African nations such as Botswana, Zambia and Zimbabwe, but are exceptionally difficult to enforce due to the logistics of tracking carnivore populations. Effects on habitat loss A 2005 paper by Nigel Leader-Williams and colleagues in the Journal of International Wildlife Law and Policy asserted that the legalization of white rhinoceros hunting in South Africa motivated private landowners to reintroduce the species onto their lands. As a result, white rhinos increased from fewer than one hundred individuals to more than 11,000. Leader-Williams's study also showed that trophy hunting in Zimbabwe doubled wildlife areas relative to state protected areas. The implementation of controlled and legalized hunting led to an increase in the area of suitable land available to elephants and other wildlife, which "reversed the problem of habitat loss and helping to maintain a sustained population increase in Zimbabwe's already large elephant population". A study in the journal Biological Conservation stated that trophy hunting is of "major importance to conservation in Africa by creating economic incentives for conservation over vast areas, including areas which may be unsuitable for alternative wildlife-based land uses such as photographic ecotourism". Financial incentives from trophy hunting effectively more than double the land area that is used for wildlife conservation, relative to what would be conserved relying on national parks alone, according to the study published in Biological Conservation. According to the American writer and journalist Richard Conniff, Namibia is home to 1,750 of the roughly 5,000 black rhinos surviving in the wild. Namibia's mountain zebra population has increased from 1,000 in 1982 to 27,000 in 2014. Elephants, which are gunned down elsewhere for their ivory, have gone from 15,000 to 20,000 in 1995. Lions, which were on the brink of extinction "from Senegal to Kenya", are increasing in Namibia. Financial support of conservation efforts The International Union for Conservation of Nature recognizes that trophy hunting, when well-managed, can generate significant economic incentives for the conservation of target species and their habitats outside of protected areas. A study published in the journal Animal Conservation and led by Peter Lindsey