Maximum rate of increase in the African Elephant

Calef, George W.

doi:10.1111/j.1365-2028.1988.tb00984.x

Cited by 51 publications

(43 citation statements)

References 2 publications

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“…Generalised linear models with normal error structure were conducted for (a) the total study area survey population estimates and (b) for the management area NG11 survey population estimates, with year of survey fitted as the explanatory variable and significance tested at p \ 0.05. We calculated the maximum growth rate for an elephant population at 7 % by Calef (1988), using a minimum inter-calving period of 3 years (ranges between 3 and 4.7 years) and a mean age of first birth of a calf at 11 years (ranges between 8 and 14 years). We compared the estimated population growth rate to this predicted maximum rate of increase.…”

Section: Population Growthmentioning

confidence: 99%

Using simulations of past and present elephant (Loxodonta africana) population numbers in the Okavango Delta Panhandle, Botswana to improve future population estimates

Songhurst

Chase²,

Coulson

2015

Wetlands Ecol Manage

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An ability to reliably estimate population numbers, trends and densities of wildlife has a prominent role in conservation and management of wetlands. We use aerial surveys and simulation techniques to explore the results of past and present elephant population surveys in the Okavango Delta Panhandle, Botswana, and use these to propose a technique of simulation to improve counts in the future. Population numbers and density estimates from past survey results show large fluctuations, which are unlikely to come from reproduction. Reasons for such variations could be attributed to imprecision in survey techniques or may be because only part of the elephant range is being surveyed. Simulated surveys of hypothetical elephant populations were used to explore the effect of different survey techniques, spatial distributions of animals and spatial scale on the precision of aerial survey population estimates and trends. Our study reveals the usefulness of using simulations to test the reliability of survey data and plan more efficient surveys. We also find that while there may be some uncertainty in individual population estimates, there is more certainty in the recorded trends. These findings reinforce the need to address elephant management in the Okavango and surrounding wetland systems and call for the urgent consideration of management strategies such as fence realignments to affect the objectives of the Kavango Zambezi Transfrontier Conservation Area (KAZA TFCA) initiative, which will help relieve elephant population pressure.

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Section: Population Growthmentioning

confidence: 99%

Using simulations of past and present elephant (Loxodonta africana) population numbers in the Okavango Delta Panhandle, Botswana to improve future population estimates

Songhurst

Chase²,

Coulson

2015

Wetlands Ecol Manage

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“…Calef (1988) predicted a maximum rate of increase for elephant populations of 7 per cent. Despite the closed nature of the Addo elephant population and the current high density (2.8 elephants per sq km), the observed population growth rate is relatively rapid, indicative of a healthy, growing population.…”

Section: Demographic Analysismentioning

confidence: 99%

Elephants in Addo Elephant National Park, South Africa: reconstruction of the population's history

Whitehouse¹,

Hall-Martin

2000

ORX

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The history of the Addo elephant population in South Africa, from the creation of the Addo Elephant National Park (AENP) in 1931 to the present (every elephant currently living within the park is known), was reconstructed. Photographic records were used as a primary source of historical evidence, in conjunction with all documentation on the population. Elephants can be identified in photographs taken throughout their life by study of the facial wrinkle patterns and blood vessel patterns in their ears. These characteristics are unique for each elephant and do not change during the individual's life. The life histories of individual elephants were traced: dates of birth and death were estimated and, wherever possible, the identity of the individual's mother was ascertained. An annual register of elephants living within the population, from 1931 to the present, was compiled, and maternal family trees constructed. Preliminary demographic analyses for the period 1976-98 are presented. The quantity and quality of photographs taken during these years enabled thorough investigation of the life histories of all elephants. Prior to 1976, insufficient photographs were available to provide reliable data on the exact birth dates and mothers' identities for every calf born. However, data on annual recruitment and mortality are considered sufficiently reliable for use in analyses of the population's growth and recovery.

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“…Previous research done in northern Botswana showed that the resident elephant populations has been increasing (Calef 1988;Melton 1975), and some reports cautioned about excessive woodland utilization by elephants and loss of woodland if elephant numbers were allowed to increase beyond a certain, yet unknown threshold (Child 1968;Moroka 1984;. Recent research (Ben-shahar 1993) has shown that elephants were inclined to utilize particular plant species and the proportion of the plants damaged by elephants depended on the distance of plants from water sources.…”

Section: Introductionmentioning

confidence: 99%

Woodland dynamics under the influence of elephants and fire in Northern Botswana

Ben-Shahar¹

1996

Vegetatio

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Sustained elephant browsing and intense burning could result in the loss of woodlands under conditions where elephant densities are high, such as in northern Botswana. Three woodland types dominated by Acacia erioloba, Baikiaea plurijuga and Colophospermum mopane were monitored in plots and contemporary recruitment rates of woody plants were compared with the associated local elephant densities and fire occurrences. Woodland types differed with respect to structure, extent of elephant damage and the occurrence of fire. Canonical correlations indicated that high extent of fire damage and high elephant densities did not covary within the woodland types investigated. Low tree densities in some woodland types were associated with high elephant densities and new elephant damage to plants increased with high elephant densities during the dry season. Plots with an apparent high fire frequency had lower tree densities and higher cover abundance of shrubs and seedlings.The annual rates of tree recruitment/loss in each woodland type were estimated through a model based on observed seedling recruitment, mortality and reversal to lower height classes due to combinations of fire occurrence and elephant browsing. The model suggested that elephants induce tree loss in woodlands dominated by plant species which are principal food sources. Fire however, seems to have a widespread effect across woodlands which could result in extensive tree loss.

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Maximum rate of increase in the African Elephant

Cited by 51 publications

References 2 publications

Using simulations of past and present elephant (Loxodonta africana) population numbers in the Okavango Delta Panhandle, Botswana to improve future population estimates

Using simulations of past and present elephant (Loxodonta africana) population numbers in the Okavango Delta Panhandle, Botswana to improve future population estimates

Elephants in Addo Elephant National Park, South Africa: reconstruction of the population's history

Woodland dynamics under the influence of elephants and fire in Northern Botswana

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