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DRY SEASON AERIAL SURVEY OF ELEPHANTS AND WILDLIFE IN NORTHERN BOTSWANA JULY – OCTOBER 2014

Authors:
  • Elephants Without Borders

Abstract and Figures

During the 2014 dry season, a fixed-wing aerial survey of elephants and wildlife was flown over the core conservation areas of northern Botswana. This aerial survey was commissioned by Elephants Without Borders (EWB) and the Department of Wildlife and National Parks (DWNP) under the auspices of the Great Elephant Census (GEC). The GEC is a continent-wide survey of African elephant populations using standardized methods to estimate elephant populations in 21 African countries. A small fixed-wing plane was used to fly a stratified sample survey, with parallel transects, over a survey area of 98425 km2. Surveyed areas included Moremi Game Reserve (GR), Chobe National Park (NP), Makgadikgadi and Nxai Pan NPs and surrounding Wildlife Management Areas (WMAs) in Ngamiland, Chobe and Central districts. The primary objective of this survey was to provide precise and accurate estimates of wildlife populations in the survey area, using repeatable, standardized methods. Secondary objectives included mapping the spatial distribution of elephants and other wildlife; determining the distribution of elephant carcasses, baobab trees and large birds; and measuring trends in wildlife populations. The 2014 survey expanded upon the 2010 dry-season aerial surveys of northern Botswana conducted by EWB through the addition of additional strata in Ngamiland west and south of the Southern Buffalo Fence as well as in the Central district. Resampling strata sampled in 2010 allowed direct measurement of recent population trends by comparing wildlife populations between 2010 and 2014. This report provides the results of this survey, including information on the spatial distribution, abundance, and trends of elephant and other wildlife populations. Maps and tables illustrating the distribution, numbers, density and trends of wildlife species in northern Botswana are provided. The survey area was divided into 49 strata that largely conformed to the boundaries of WMAs and protected areas. Within each stratum, transects were parallel and regularly spaced between 2 and 10 km apart. To improve the precision of population estimates, sampling intensity in 46 strata ranged from 4 – 20%. In three strata, we conducted total counts in which the entire stratum was surveyed so that the population estimates are complete counts of all animals present. The overall sampling intensity was 12 %. Overall mean search effort was 1.3 km2 per minute. Aerial surveys often underestimate wildlife numbers, with the degree of underestimation higher for small or cryptic species than for large species. High-resolution, wide-angle digital cameras were used to compensate for any underestimated herd sizes or missed animals. The locations of wildlife herds seen during the survey were entered into a GIS to produce maps showing the distribution and herd sizes of principal large herbivores and birds in northern Botswana. The estimated number of fresh elephant carcasses and older remains (bones) was 9694 for the entire survey area and represented 6.9% of the total number of live and dead elephants. Of that total, an estimated 123, or 0.09% of the total population of live and dead elephants, were fresh carcasses indicating death within the past year. This ratio decreased from 0.5% in the 2010 survey. The highest carcass ratios and densities occurred in the Okavango Panhandle and Chobe Enclave, where arable farming is part of the land use, as well as along the Chobe Riverfront near the Namibian border.
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... Botswana: An estimated total of between 2,000 and 4,000 hippos was reported in 2016, comprising 2-3% of the estimated global hippo population. However, these estimates were based on census studies first made in 1993 (Chase et al., 2018). Updated census data in 2018 estimated a total of 13,232 hippos in northern Botswana, comprising 10-12% of an updated total global population and meaning the country contains one of the largest hippo populations in Africa (Chase et al., 2018). ...
... However, these estimates were based on census studies first made in 1993 (Chase et al., 2018). Updated census data in 2018 estimated a total of 13,232 hippos in northern Botswana, comprising 10-12% of an updated total global population and meaning the country contains one of the largest hippo populations in Africa (Chase et al., 2018). The declining population trend reported in 2016 likely resulted from a period of extended drought and low flooding resulting in scarce food and water availability (Chase et al., 2018). ...
... Updated census data in 2018 estimated a total of 13,232 hippos in northern Botswana, comprising 10-12% of an updated total global population and meaning the country contains one of the largest hippo populations in Africa (Chase et al., 2018). The declining population trend reported in 2016 likely resulted from a period of extended drought and low flooding resulting in scarce food and water availability (Chase et al., 2018). The hippo population in northern Botswana between 2014 and 2018 increased significantly, particularly within the Okavango Delta (Chase et al., 2018). ...
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Technical Report
CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) wasopened for signature in Washington DC on 3rd March 1973, and to date has 184 Parties from across the world. If CITES is to remain a credible instrument for conserving species affected by trade, the decisions of the Parties must be based on the best available scientific and technical information. Recognizing this, IUCN and TRAFFIC have undertaken technical reviews of the proposals to amend the CITES Appendices submitted to the Nineteenth Meeting of the Conference of the Parties to CITES (CoP19). The Analyses - as these technical reviews are known - aim to provide as objective an assessment as possible of each amendment proposal against the requirements of the Convention, as agreed by Parties and laid out in the listing criteria elaborated in Resolution Conf. 9.24 (Rev. CoP17) and other relevant Resolutions and Decisions. To ensure the Analyses are as accessible as possible to all Parties, we have created a bespoke webpage where the Analyses can be downloaded individually by proposal or in full (see https://citesanalyses.iucnredlist.org/).
... DWNP surveyed primarily in earlier years (1996, 1999, 2001-2006, also 2012-2013) whereas EWB surveys were carried out in recent years (2010, 2014, and 2018). Detailed methodology is available (Chase, 2011;Chase et al., 2015Chase et al., , 2018Department of Wildlife & National Parks, 1996, 2001, 2003, 2004, 2005, 2006, 2012 but briefly described here, including differences in survey effort between the two organisations. Different areas were surveyed each year; therefore, we restricted our analyses to the area that was intersected by all surveys, which included most of the Delta (Figure 1). ...
... Observers scanned for all large herbivores (including hippos), recording the number of animals seen and their GPS location. Large groups were photographed during EWB surveys to verify or correct the numbers of animals seen by observers (Chase, 2011;Chase et al., 2015Chase et al., , 2018, which is a recommended technique to improve the accuracy of hippo counts (Bouché, 2008;Jachmann, 2001). The hippo population was estimated for each stratum by dividing the total number of hippos counted in transects by the searched transect area, then extrapolating for total stratum area (i.e. ...
... In 2018, there were an estimated 12,576 hippos in the Delta and surrounding areas, representing 95% of Botswana's hippo population (Chase et al., 2018), and ranking the country third behind Tanzania and Zambia (Lewison & Pluháček, 2017), two long established hippo strongholds. Our lower estimate in 2018 of 9,655 hippos reflects our restricted study area, which excluded the southern and western extents of the Delta and the Linyanti and Kwando River systems. ...
Article
• Conservation requires reliable estimates of a species' population and their spatial distribution. Knowledge of large-scale habitat use and population trends in common hippopotamus (Hippopotamus amphibius; hereafter hippo) in wetland ecosystems is limited, with no studies of hippo populations in the Okavango Delta (the Delta), Botswana. • We examined the drivers of long-term trends and spatial patterns in the Delta's hippo population, using 13 years of aerial surveys (1996–2018) informing on the potential impacts of changes in inflow, flooding patterns and rainfall on hippo populations. • We estimated temporal changes in hippo populations and relationships with rainfall and inflow. We also examined how spatially explicit hippo counts related to flood and surface water extent and vegetation class at different scales. • The Delta's hippo population has increased, probably due to increasing long-term rainfall and inflow, following a period of severe drought/low flooding. Hippos were positively associated with areas with high variation in flooding and negatively associated with broad-scale surface water extent, indicating hippos avoided permanent swamps and main channels, probably due to water depth, lack of nearby grazing, and thick riparian vegetation. At a fine scale, hippos relied on large lagoons for daytime refuge. • The most recent population estimate indicates that Botswana has the third highest hippo population in Africa, reflecting the importance of the Delta. Reductions in inflow and rainfall from climate change and water resource development would threaten these hippo populations by reducing grazing availability, lagoon sizes, and seasonal swamps. Ongoing monitoring of hippos should continue as they represent a good indicator for the entire floodplain ecosystem.
... Botswana has the largest elephant population in Africa with approximately 130,000 individuals (Chase et al., 2019), together with one of the lowest human populations of all African countries (~2.3 million) (World Bank Database, 2019). Botswanan wildlife management authorities are concerned about the effect that the large elephant populations will have on expanding urban and agricultural development, and they predict increases in human-elephant conflict (HEC) over space and resources (Government of Botswana, 2021). ...
... There are four recognised seasons within northern Botswana: cold dry season (May-July), hot dry season (August-October), wet season (November-March) and post-wet season (April) (Adams et al., 2017). There are approximately 32,700 elephants in Chobe District, with an estimated 15,000 of them in Chobe National Park (Chase et al., 2019). Chobe district is an unfenced area, where wildlife can move freely throughout the different land-use designations. ...
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The global impact of increased human activities has consequences on the conservation of wildlife. Understanding how wildlife adapts to increased human pressures with urban expansion and agricultural areas is fundamental to future conservation plans of any species. However, there is a belief that large wild free-ranging carnivores and ungulates, cannot coexist with people, limited studies have looked at wildlife movements through differing human-dominated landscapes at finer spatial scales, in Africa. This information is vital as the human population is only going to increase and the wildlife protected areas decrease. We used remote-sensor camera traps to identify the movement patterns of African elephant (Loxodonta africana) through six wildlife corridors in Botswana. The wildlife corridors were located in two different human-dominated landscapes (agricultural/urban), with varying degrees of human impact. While we found that elephants use corridors in both landscapes, they use the urban corridors both diurnally and nocturnally in contrast to agricultural corridors which were only nocturnal. Our results provide evidence for temporal partitioning of corridor use by elephants. We identified that seasonality and landscape were important factors in determining the presence of elephants in the corridors. Our findings demonstrate that elephant diel patterns of use of the wildlife corridor differs based on the surrounding human land-uses on an hourly basis and daily basis, revealing potential adaptation and risk avoidance behaviour.
... Vegetation in the MPNP can be classified into five broad categories (Brooks, 2005): dense acacia woodland with some stands of Dichrostachys cinerea, along the edges of the Boteti River, dominated by Schmidtia kalahariensis grasses; open acacia woodland dominated by Vachellia erioloba trees and Stipagrostis uniplumis and Digitaria eriantha grasses; Schmidtia pappaphoroides grasslands dotted with isolated stands of Hyphaene petersiana palms; pan grassland around the edge of the salt pans dominated by Cenchrus ciliaris and Sporobolus ioclados; and mixed woodland dominated by Colophospermum mopane and Combretum imberbe with S. ioclados grasses (Fig. 1). Plains zebra and blue wildebeest are the most numerous large herbivores, with approximately 24,000 of the former and 10,000 of the latter (Chase et al., 2018). ...
... Aerial surveys of wildlife in Botswana are conducted every four years by the Department of Wildlife and National Parks (DWNP), most recently during the 2010 rainy season and the 2014 and 2018 dry seasons in conjunction with Elephants without Borders (Chase, 2010;Chase et al., 2015;Chase et al., 2018). The surveys are structured by area, including the East (rainy season range) and West (dry season range) Makgadikgadi. ...
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In migratory tropical ecosystems governed by water availability, artificially altering water availability can affect herbivore distribution and movement. The Makgadikgadi Pans, Botswana, sustains approximately 10,000 blue wildebeest (Connochaetes taurinus) and 24,000 plains zebra (Equus quagga) migrating between a dry season range with permanent water and a rainy season range with productive grasses. Artificial water points (AWPs) have been created by pumping some natural waterholes in the rainy season range. We combined data from aerial surveys and from GPS collars on 20 and 12 zebra pre- and post-AWP installation, respectively, and on 17 wildebeest post-AWP, to test hypotheses relating to large- and small-scale movement patterns. Post-AWP, a higher proportion of wildebeest, but not zebra, were in the rainy season range during the dry season. Post-AWP zebra migration to their rainy season range occurred longer after rainfall cessation than pre-AWP, though this period was still shorter than that of wildebeest (one month compared to three). The effect of proximity to waterholes on probability of space use varied seasonally for both species and followed opposing trends, suggesting resource partitioning or competition effects. Both species visited AWPs more than natural waterholes, particularly wildebeest in the dry season. Wildebeest movement patterns were more likely to be disturbed by AWPs, which could cause the development of residency and reduce population resilience. Management interventions, such as AWPs, can affect species to different extents, so the responses of several species should be assessed to determine the level of disturbance to migratory ecosystem resilience and functioning.
... Botswana is endowed with a variety of wildlife resources including an estimated 130,000 elephants (Chase et al., 2018). However, Botswana is faced with opposition from the animal rights groups about the re-introduction of hunting which was announced in 2019. ...
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... Here, we focused on large carnivores, but our approach can be extended to any other species or taxa with data available at extensive temporal and spatial scales (e.g. Chase et al., 2018;Keeping, 2014). We stress that nationwide approaches and collaborations such as the one presented in this study are crucial to drawing inferences at adequate biological and spatial scales, to develop research priorities, and for the implementation of evidence-based conservation and management strategies. ...
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Aim Assessing the distribution and persistence of species across their range is a crucial component of wildlife conservation. It demands data at adequate spatial scales and over extended periods of time, which may only be obtained through collaborative efforts, and the development of methods that integrate heterogeneous datasets. We aimed to combine existing data on large carnivores to evaluate population dynamics and improve knowledge on their distribution nationwide. Location Botswana. Methods Between 2010 and 2016, we collated data on African wild dog, cheetah, leopard, brown and spotted hyaena and lion gathered with different survey methods by independent researchers across Botswana. We used a multi-species, multi-method dynamic occupancy model to analyse factors influencing occupancy, persistence and colonization, while accounting for imperfect detection. Lastly, we used the gained knowledge to predict the probability of occurrence of each species countrywide. Results Wildlife areas and communal rangelands had similar occupancy probabilities for most species. Large carnivore occupancy was low in commercial farming areas and where livestock density was high, except for brown hyaena. Lion occupancy was negatively associated with human density; lion and spotted hyaena occupancy was high where rainfall was high, while the opposite applied to brown hyaena. Lion and leopard occupancy remained constant countrywide over the study period. African wild dog and cheetah occupancy declined over time in the south and north, respectively, whereas both hyaena species expanded their ranges. Countrywide predictions identified the highest occupancy for leopards and lowest for the two hyaena species. Main Conclusions We highlight the necessity of data sharing and propose a generalizable analytical method that addresses the challenges of heterogeneous data common in ecology. Our approach, which enables a comprehensive multi-species assessment at large spatial and temporal scales, supports the development of data-driven conservation guidelines and the implementation of evidence-based management strategies nationally and internationally.
... It appears that there was definitely an increase in poaching in some parts of Botswana, including the Okavango World Heritage Site and its buffer zone areas (Rogan et al 2017;Chase et al 2018;Schlossberg, Chase, and Sutcliffe 2019). The degree to which this poaching is due to the actions of local community members as opposed to internationally supported criminal gangs is open to question. ...
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Many governments and conservation organisations have argued that hunter-gatherers, farmers and pastoralists are responsible, in considerable part, for environmental degradation and biodiversity losses in southern Africa. Particular attention has been paid to alleged wildlife losses, especially elephants in Botswana. This article considers some of the issues surrounding hunting bans and protected areas with a view to conserving elephants. In Botswana, local people were removed from protected areas after being blamed for declines in wildlife numbers. Utilising government and other scientific wildlife data, the hunting ban cannot be shown to have had any significant impact on the conservation of elephants and other game species. Local people argue that many of their activities are sustainable, maintaining that they are generally not responsible for biodiversity losses and environmental degradation. Population growth, the expansion of agricultural, livestock and mining activities, the construction of veterinary cordon fences and increases in water point distribution have led to localised environmental degradation. The ‘great elephant debate’ became an important political issue during the run-up to the Botswana elections of October 2019. Local communities sought to ensure that they would be able to obtain benefits from wildlife tourism which had been denied them during the hunting ban.
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The Okavango Delta is renowned as an extraordinary ecosystem of high biodiversity, listed as both a Ramsar and World Heritage Site, with part protected in the Moremi Game Reserve. This extensive floodplain ecosystem has 444 recorded bird species, with just under a quarter of these waterbirds, including at least 16 breeding and 4 threatened (1 endangered, 3 vulnerable) species. Despite the global importance of this ecosystem, and its transboundary nature, there are surprisingly few long-term assessments of status of the ecosystem or waterbird communities, a key indicator of ecosystem health, with threats such as upstream water extraction, and climate change threatening its outstanding biodiversity. We compiled a comprehensive 53-year dataset comprised of citizen science and other datasets (1970-2019), on 36 waterbird species (Anhingidae, Ardeidae, Ciconiidae, Gruidae, Pelecanidae, Phalacrocoracidae, and Phoenicopteridae), including eight waterbird breeding colonies in the Okavango Delta. We investigated trends in waterbird biodiversity as well as responses to temperature, flow, flooding, and local rainfall. Waterbird breeding colonies were associated with relatively high areas of riparian woodland, and experienced moderate flooding frequencies (> 1 in 5 years). Total abundance of all 36 waterbird species was positively related to river flows. Despite increased citizen science effort over time, total abundance within the Okavango Delta significantly declined with declining average inundation. Four species led these declines (African darter Anhinga rufa, green-backed heron Butorides striata, slaty egret Egretta vinaceigula, squacco heron Ardeola ralloides) and one marabou stork Leptoptilos crumenifer, increasing (only sufficient data to analyse 15 species individually). Decreased inundation within the Delta and other internal factors (urbanisation, tourism, vegetation change) as well as external factors (habitat loss elsewhere) are likely driving these declines. Rigorous monitoring of waterbirds, including the eight breeding colonies across the Delta, is needed to explore these changes closely, providing baselines in the case of water resource developments on the rivers supplying the Okavango Delta. Long-term conservation of the magnificent Okavango Delta and its dependent biodiversity, including its waterbirds, is highly reliant on protection of river flows in three countries to ensure natural flooding regimes, alongside the conservation of neighbouring wetlands.
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Technical Report
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We conducted wet [26 March-4 April 2003 (Apr03)] and dry [1-8 November 2005 (Nov05)] season aerial surveys of African elephants (Loxodonta africana Blumenbach) in the Caprivi Strip, Namibia to provide an updated status report on elephant numbers and distribution and assist with a historical analysis of elephant distribution and abundance in the Caprivi Strip. During the wet season when water was available in seasonal pans, elephants were widely distributed throughout the survey area. In contrast, during the dry season, a majority of elephant herds occurred within 30 km of the perennial Kwando, Linyanti and Okavango rivers and few herds occurred within the West Caprivi Game Reserve where water in the seasonal pans was limited. We estimated 5318 elephants for the 7731-km(2) survey area (0.71 elephants km(-2)) for the Apr03 wet season survey and 6474 elephants for the 8597-km(2) survey area (0.75 elephants km(-2)) for the Nov05 dry season survey. Based on our aerial surveys and reports of elephant numbers and distribution from historical aerial surveys and telemetry studies, civil war, veterinary fences and human activities appear to have effected changes in African elephant abundance, distribution and movements in the Caprivi Strip, Namibia since 1988 when the first comprehensive aerial surveys were conducted.
Ecology of elephants in the Okavango Delta
  • M J Chase
Chase, M.J. (2010) Ecology of elephants in the Okavango Delta. Elephants Without Borders, Kasane, Botswana.