Size Matters
Protection rescued Africa’s savanna elephants from looming extinction. We continue to have thriving populations in many protected areas thanks to early conservation initiatives, but only in five of these does the elephant population exceed 10,000 elephants. These I consider the strongholds for elephants. They also are bastions of biodiversity conservation and are world-renowned for their wildlife.
Elephant populations in most protected areas number 1,000 to 10,000, but those where elephants are fenced in usually have fewer than 500. Low numbers also occur in several buffer areas where people live and harass wildlife. This does not imply that smaller populations do not contribute to the species’ well-being – they certainly do. In some cases, lower numbers reflect ecological limitations, but in others, the continuing exploitation erodes populations despite extraordinary efforts to control exploitation.
Strongholds have several things in common. They are large core protected areas connected to buffers. They have ample water supplies, either from rivers or artificially maintained ponds. They are not fenced but well protected by well-trained personnel with the necessary infrastructure. Governments and NGOs support them, they are included in transfrontier conservation incentives and have programmes to help neighbouring communities. Four of them are popular tourist destinations.
Strongholds include the following national parks:
The Kruger National Park in northeastern South Africa covers 19,485 square kilometres. Kruger has been incorporated into the Great Limpopo Transfrontier Park by removing its fences along the Zimbabwean and northeastern Mozambican border, providing continuous roaming space over at least 35,000 square kilometres. In 1993, the fences between Kruger and game reserves to the park’s west were removed entirely. Additionally, in 2002, sections of the fence separating Kruger and the Limpopo National Park in Mozambique were removed to create the Great Limpopo Transfrontier Park.
Before 1890, hunters devastated this elephant population to near extirpation. Our recent genetic study showed that the population recovered through dispersal from several areas rather than a single source, as previously suggested. Elephant populations in southern Kruger originated from those south of Kruger, while populations in the northern parts of the park originated from regions to the north and west of Kruger. Also, Kruger’s elephant population does not suffer the negative genetic consequences that may be due to isolation. Furthermore, it now forms part of a functional entity in which migration has helped to maintain a relatively diverse gene pool.
Our analyses of census data collected yearly since 1967 show that a rapid increase in elephant numbers followed the end of culling in 1994. This sharp increase continued for some 10 years, but since 2003, the growth rate has slowed.
The Gonarezhou National Park, founded in 1975 in the southeast lowveld of Zimbabwe, presently supports at least 10,000 elephants in an area of about 5,000 square kilometres. These elephants are considered part of the larger population of the Great Limpopo Transfrontier Conservation Area. Gonarezhou is no longer fenced – those erected in the late 1960s had been wholly vandalised by the late 1990s. However, an electrified fence erected in 2016 restricts elephant movements into Mozambique while fences on two sections in the north-western border of the park also restrict elephant movements.
The Save and Runde Rivers flow throughout the year in the park. Other smaller rivers are seasonal. Rainfall is low but variable, and droughts, elephants and fires continuously alter vegetation dominated by mopane shrubland or woodland, wooded and bushed grassland, dry deciduous woodland, and riverine woodland.
Habitat deterioration prompted management to institute culling, and 10,657 elephants were culled from 1964 to 1993. The concern of conservation practitioners and management authorities at the time was that this population had deleterious effects on other components of biodiversity. Their concern was valid. Our analysis of population estimates since 2010 suggests that the population is no longer increasing. However, the number of elephants in areas along the boundary of Gonarezhou is increasing, most likely due to the movement of elephants to neighbouring areas.
The Hwange National Park covers about 15,000 square kilometres of semi-arid savannas on the northwestern border of Zimbabwe. Some 40,000 elephants now live here – more than in any other African national park. The park is part of Africa’s largest transfrontier conservation area (the Kavango-Zambezi landscape), where elephants can mostly roam at liberty.
Hwange was established in 1928. It is not fenced, so elephants can and do move in and out of the park and into neighbouring Botswana. Veterinary fences along portions of the southern and western boundaries limit movements. There are no large rivers, and the few streams that drain from high-lying areas flow only sporadically. Wetlands and natural pans fill with water during the summer rainy season. During the dry season, most animals roam relatively close to water holes. This allows wildlife to disperse widely throughout the park.
Elephant numbers in Hwange have been fluctuating widely. Water supplementation probably attracted elephants to this typically harsh and dry area during the extended non-rainy season. Water provisioning gave rise to the year-round elephants in Hwange. The population stabilised in 1995, and growth since then fluctuated around zero. Like elsewhere in southern Africa, this year-round presence of elephants at high numbers and high local densities changed woodlands into shrublands that could be more appealing to most visitors. But recent research shows that changes in the vegetation have stabilised over the last 20 years. Our recent demographic assessment of the population shows that relatively high juvenile mortality and not reduced breeding stabilised the population.
Elephants were already present when the Chobe National Park in northern Botswana was established in 1961 and officially proclaimed in 1968. Chobe is 10,590 square kilometres in extent and is not fenced. The Chobe River forms its northern boundary, and in the hinterland, the park’s neighbours mainly comprise protected wildlife or forestry areas. The elephant population has not been managed, but for the possible effects of placing 18 water holes on movement. These water points were established in an attempt to reduce human-wildlife conflict in the Kasane area, as well as reduce elephant concentrations along the Chobe River.
The elephants in Chobe National Park are at the core of Africa’s largest continuous population of savanna elephants. For at least 80 years, the populations in Chobe have been protected by law and not exposed to large-scale poaching, but for incidences reported during 2018.
This elephant population of Botswana represents about 50 per cent of the remaining savanna elephants in Africa. Elephants in this region have not been culled except for licensed trophy hunting and the killing of ‘problem’ elephants. Collectively, these account for fewer than 1,000 elephants. The region named the Kavango-Zambezi Transfrontier Conservation Area comprises a variety of conservation-related land use practices. Here elephants can roam over 440,000 square kilometres and regularly cross borders between the southern African countries of Angola, Botswana, Namibia, Zambia and Zimbabwe.
The population within the Chobe National Park in Botswana is surprisingly unstable, comprising of about 10,000 elephants in 1975, 45,000 in 2010, and around 15,000 at the last census in 2018. The year-to-year fluctuations in numbers here are most probably due to dispersal, with elephants free to move in and out of Chobe. Our demographic assessment supports this notion as the yearly growth rate resulting from birth and death rates has been stable at around zero for at least 10 years. Here, we may have a functional metapopulation that stabilises regional populations through dispersal.
Our time series analyses were constructed from population estimates across Botswana and immediate neighbouring populations sharing elephants with Botswana show that elephant numbers for the entire region have been stable for the past 24 years (a generation length for elephants). Yearly growth rates of specific populations over these 24 years varied considerably but were generally low and seldom differed significantly from zero (but for Chobe District East and the Makgadikgadi Pans). All these populations are administrative subunits of a continuous entity, with dispersal between the subunits only in some places being hindered by fences maintained to control the spread of animal diseases or to demarcate the borders between countries.
The South and North Luangwa National Parks in Zambia are at the end of Africa’s Great Rift Valley. The Luangwa River, one of the main tributaries of the Zambezi River, flows through the Luangwa Valley for a distance of about 700 kilometres. The Luangwa River sustains wildlife throughout the year. It flows along the eastern boundary of the parks with a wealth of lagoons and oxbow lakes in its wake. This lush landscape supports some of the greatest concentrations of wildlife in Africa.
South and North Luangwa National Parks are at the core of the Luangwa Valley cluster of conservation areas covering a total area of 73,769 square kilometres. At the end of the 1970s, 88,000 elephants lived here – far more than the 15,000 that now roam the valley. Poaching in the 1980s and early 1990s was primarily responsible for this precipitous decline. Our assessment of trends over the last 24 years suggests that the population of North Luangwa National Park is stable, while that of South Luangwa National Park is decreasing exponentially.
Collectively, these five strongholds account for 100,000 elephants.