Elephant Population Biology and Ecology

Aarde, Rudi J. van; Ferreira, Sam M.; Jackson, T. P.; Page, Bruce R.; Beer, Y. de; Gough, K. F.; Guldemond, Robert; Junker, Jessica; Olivier, Pieter I.; Ott, Theresia

doi:10.18772/22008034792.13

Cited by 35 publications

(41 citation statements)

References 113 publications

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“…In contrast to our hypothesized negative relationship between reserve size and elephant FGMs, reserve size alone explained 0.36% of the observed variation. Therefore, despite remaining lower than the density of elephants at the donor site [Kruger National Park, 0.63 elephants per km 2 ; (van Aarde et al, 2008)] and receiving a low amount of model support (Table 2), elephant density explained 45% of the observed variation in FGM concentrations. 2).…”

Section: Resultsmentioning

confidence: 94%

Delayed physiological acclimatization by African elephants following reintroduction

2013

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Managers of reintroduced wildlife commonly encounter behavioral problems post-release that have been linked to physiological condition and elevated stress hormone concentrations. However, there is uncertainty about the generality of a stress response among populations, factors influencing the intensity of the response and the amount of time needed to physiologically acclimatize. We evaluated the relationship of temporal, climatic and social factors to stress hormone concentrations in five African elephant (Loxodonta africana) populations following reintroduction. We determined fecal glucocorticoid metabolite concentrations (FGMs) in 1567 fecal samples collected from elephants reintroduced to five fenced reserves with differing reintroduction histories in South Africa during 2000-2006. Variation in FGMs across the five reserves was best explained by the number of years that elapsed since initial release. Compared with FGMs 1 year after release, FGMs were 10% lower 10 years after release and 40% lower 24 years after release. Across all reserves, FGMs were consistently highest in the dry season, although daily and monthly temperature and rainfall were not as important as other factors. FGMs did not vary solely in relationship to reserve size or elephant density. Our findings suggest that regardless of reintroduction site conditions, elephants and likely other species subject to reintroduction require an extended period of time to physiologically acclimatize to their new surroundings. Managers should prepare for prolonged behavioral and physiological consequences of long-term elevated stress responses following reintroduction, such as restricted space use and aggressive behavior. bs_bs_banner Animal Conservation. Print ISSN 1367-9430 Animal Conservation 16 (2013) 575-583

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Section: Resultsmentioning

confidence: 94%

Delayed physiological acclimatization by African elephants following reintroduction

2013

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“…In this paper, we study the influence of the spatial scaling of environmental context on habitat selection by African elephants in Kruger National Park, South Africa. We focus specifically on the scaling of the elephants’ response to food and water resources, because these are known to be key determinants of elephant distribution (Chamaille‐Jammes, Valeix & Fritz 2007a,b; Smit, Grant & Devereux 2007a; Smit, Grant & Whyte 2007b; Van Aarde et al. 2008).…”

Section: Introductionmentioning

confidence: 99%

“…We aimed at testing whether the explicit consideration of environmental context at appropriate scales improves the understanding and predictability of habitat selection by elephants. We differentiate between dry and wet season habitat selection, since water is widely available during the wet season, whereas seasonal water sources dry up in the dry season (Van Aarde et al. 2008).…”

Section: Introductionmentioning

confidence: 99%

The spatial scaling of habitat selection by African elephants

Knegt

Langevelde

Skidmore

et al. 2010

Journal of Animal Ecology

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Summary1. Understanding and accurately predicting the spatial patterns of habitat use by organisms is important for ecological research, biodiversity conservation and ecosystem management. However, this understanding is complicated by the effects of spatial scale, because the scale of analysis affects the quantification of species-environment relationships. 2. We therefore assessed the influence of environmental context (i.e. the characteristics of the landscape surrounding a site), varied over a large range of scales (i.e. ambit radii around focal sites), on the analysis and prediction of habitat selection by African elephants in Kruger National Park, South Africa. 3. We focused on the spatial scaling of the elephants' response to their main resources, forage and water, and found that the quantification of habitat selection strongly depended on the scales at which environmental context was considered. Moreover, the inclusion of environmental context at characteristic scales (i.e. those at which habitat selectivity was maximized) increased the predictive capacity of habitat suitability models. 4. The elephants responded to their environment in a scale-dependent and perhaps hierarchical manner, with forage characteristics driving habitat selection at coarse spatial scales, and surface water at fine spatial scales. 5. Furthermore, the elephants exhibited sexual habitat segregation, mainly in relation to vegetation characteristics. Male elephants preferred areas with high tree cover and low herbaceous biomass, whereas this pattern was reversed for female elephants. 6. We show that the spatial distribution of elephants can be better understood and predicted when scale-dependent species-environment relationships are explicitly considered. This demonstrates the importance of considering the influence of spatial scale on the analysis of spatial patterning in ecological phenomena.

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“…Using these two density figures, it is possible that within 100 km of the Limpopo and Shashe River's confluence, an area of 31,416 km 2 , there may have been an elephant population of between 19,164 and 36,527 individuals. It is highly likely that the average density was in fact higher than it is today since elephant movement and distribution is currently heavily restricted by humans (Hoare & Du Toit 1999;van Aarde et al 2008;Graham et al 2009;Selier et al 2014). During the first and beginning of the second millennia AD, this impact would have been less intensive since the local human population was low; elephants may have maintained much of their original mobility habits, possibly only avoiding agriculturalist homesteads.…”

Section: Population and Mortalitymentioning

confidence: 99%

“…We would therefore expect between 9300 (0.61 elephants/km²) and 18,599 (1.22 elephants/km²) tusk-bearing elephants in the area. We can then use the average mortality rate recorded in elephant populations, found to be between 1 and 5 % per annum (see Moss 2001;van Aarde et al 2008), to calculate the number of carcasses on the landscape and the number of collectable tusks. Based on this, there may have been between 194 and 386 tusk-bearing carcasses available for exploitation per year, resulting in between 369 (1 tusk/85 km² [using 31,416 km²]) and 734 (1 tusk/43 km²) actual tusks (Tab.…”

Section: Population and Mortalitymentioning

confidence: 99%