Application of distance sampling to estimate population densities of large herbivores in Kruger National Park

Aerial surveys have been used in the Kruger National Park, South Africa, to count large ungulates since the late 1970s. After 1998, aerial line-transect sampling using fixed-wing aircraft and Distance analyses replaced the ‘total’ counting method. This paper investigates these methods and three sampling intensities for estimating the densities of nine large ungulate species in Kruger National Park. Estimates suitable for the detection of population trends and making management decisions were decided by examination of coefficients of variation (set <20%, a priori). Despite the likely violation of some key assumptions of Distance sampling methods, analyses gave population estimates with adequate coefficients of variation for monitoring trends in impala, giraffe, zebra, kudu, white rhinoceros, and elephant bull populations. Significant improvements in precision were obtained at higher sampling intensities for kudu, giraffe, bull elephants and white rhinoceros, but these species already had sufficiently precise population estimates for the detection of trends at the lowest sampling intensity (15%). The estimates for warthog, wildebeest and waterbuck populations were, however, insufficiently precise for assessing population trends. Increasing sampling intensity to 22% and higher did not significantly increase the precision of the Distance estimates for these species. Shortcomings in interpretation of the data caused by violations of critical assumptions of analyses are identified and discussed.

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Population estimates of Endangered Mongolian saiga Saiga tatarica mongolica: implications for effective monitoring and population recovery

Oryx ◽

10.1017/s0030605309990858 ◽

2010 ◽

Vol 44 (2) ◽

pp. 285-292 ◽

Cited By ~ 11

Author(s):

Julie K. Young ◽

Kim M. Murray ◽

Samantha Strindberg ◽

Bayarbaatar Buuveibaatar ◽

Joel Berger

Keyword(s):

Distance Sampling ◽

Iucn Red List ◽

Population Trends ◽

Population Estimates ◽

Line Transect ◽

Population Recovery ◽

Saiga Tatarica ◽

Survey Protocol ◽

Global Population

AbstractThe global population of saiga Saiga tatarica, categorized as Critically Endangered on the IUCN Red List, declined by > 95% at the end of the 20th century, resulting in several conservation initiatives to protect the species. Previously used methods to monitor population trends were inadequate to assess numbers of saiga properly. We report findings from the first survey for Mongolian saiga S. tatarica mongolica to utilize statistically rigorous methodology, using line transect distance sampling in 2006 and 2007 to obtain population estimates in and around the Sharga Nature Reserve, the southern part of the species' current range. We estimate a density of 0.54 and 0.78 saiga km-2 in 2006 and 2007, respectively. Our best models suggest that 4,938 (95% confidence interval, CI = 2,762–8,828) saiga occupied the 4,524-km2 study area in 2006 and 7,221 (95% CI = 4,380–11,903) occupied the 4,678-km2 study area in 2007. Although these estimates, with their large confidence intervals, preclude an assessment of the impacts of conservation initiatives on population trends, they suggest that the Mongolian saiga population is larger than previous reports based on minimum counts, and adequate to support in situ population recovery. Modifications to the survey protocol hold promise for improving the precision of future estimates. Distance sampling may be a useful, scientifically defensible method for monitoring saiga population trends and assessing the effectiveness of conservation efforts to stabilize and recover populations.

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Radio transmitter implants in the horns of both the white and the black rhinoceros in the Kruger National Park

Koedoe ◽

10.4102/koedoe.v34i2.425 ◽

1991 ◽

Vol 34 (2) ◽

Cited By ~ 2

Author(s):

D.J. Pienaar ◽

A.J. Hall-Martin

Keyword(s):

National Park ◽

Kruger National Park ◽

Black Rhinoceros ◽

Radio Transmitter ◽

Related Difference ◽

White Rhinoceros ◽

Radio Transmitters

The procedure for implanting radio transmitters into the horns of white and black rhinoceroses is described. Mean transmitter life in the white rhinoceros was 13,9 months which is significantly longer than the 9,7 months in black rhinoceros. In the white rhinoceros a significant sex-related difference in transmitter life was found with the transmitters in males lasting a mean of 12,1 months compared to the 15,3 months in females.

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Baseline Hematologic Results for Free-ranging White Rhinoceros (Ceratotherium simum) in Kruger National Park, South Africa

Journal of Wildlife Diseases ◽

10.7589/2015-03-081 ◽

2015 ◽

Vol 51 (4) ◽

pp. 916-922 ◽

Cited By ~ 3

Author(s):

Michele Miller ◽

Peter Buss ◽

Rachel Wanty ◽

Sven Parsons ◽

Paul van Helden ◽

...

Keyword(s):

South Africa ◽

National Park ◽

Kruger National Park ◽

Ceratotherium Simum ◽

White Rhinoceros ◽

Free Ranging

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Notes on wild dog Lycaon pictus and lion Panthera leo population trends during a drought in the Kruger National Park

Koedoe ◽

10.4102/koedoe.v38i1.309 ◽

1995 ◽

Vol 38 (1) ◽

Cited By ~ 9

Author(s):

M.G.L. Mills

Keyword(s):

National Park ◽

Kruger National Park ◽

Population Trends ◽

Adult Survival ◽

Panthera Leo ◽

Lycaon Pictus ◽

Drought Period ◽

In The Wild ◽

High Predation ◽

Wild Dog

Wild dog Lycaon pictus and lion Panthera leo populations in the Kruger National Park appeared to undergo an increase during a drought period in the early 1990s. Newly established packs, high adult survival and pup productivity contributed to an increase in the wild dog population and evidence for high predation success during the height of the drought is presented. An increase in the lion density between 1989 and 1993 on the northern basalt plains, as well as changes in the structure of the population, seem to be related to changes in prey populations, particularly to a decline in numbers and condition of buffalo Syncerus cafer.

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Some aspects of the history and population ecology of the tsessebe damaliscus lunatus lunatus in the Kruger National Park

Koedoe ◽

10.4102/koedoe.v20i1.937 ◽

1977 ◽

Vol 20 (1) ◽

Cited By ~ 3

Author(s):

S.C.J. Joubert ◽

P.J.L. Bronkhorst

Keyword(s):

Sex Ratio ◽

Population Ecology ◽

Age Structure ◽

National Park ◽

Kruger National Park ◽

Population Trends ◽

Social Organisation ◽

Developmental History ◽

The Social ◽

History Of

The population trends and distribution of the tsessebe population of the Kruger National Park are evaluated in terms of the available data derived from records compiled in the developmental history of the Kruger National Park (KNP). The recent numerical status of the population is also given. A description of the habitats favoured by tsessebe in the KNP is presented as well as an analysis of the age structure and sex-ratio of the population. Aspects of the social organisation of tsessebe affecting the interpretation of the age structure and sex-ratio phenomena of the population, are also discussed.

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Estimating abundance of the Endangered onager Equus hemionus onager in Qatruiyeh National Park, Iran

Oryx ◽

10.1017/s0030605311001827 ◽

2013 ◽

Vol 47 (2) ◽

pp. 266-272 ◽

Cited By ~ 3

Author(s):

Mahmoud-Reza Hemami ◽

Moslem Momeni

Keyword(s):

Growth Rate ◽

Protected Area ◽

National Park ◽

Natural Populations ◽

Distance Sampling ◽

Line Transect ◽

Management Interventions ◽

Equus Hemionus ◽

Wild Ass ◽

Semi Arid

AbstractHistorically, the onager or Persian wild ass Equus hemionus onager, endemic to Iran, was widespread on the arid and semi-arid central steppes but only two natural populations remain. We estimated the population density of the onager in Qatruiyeh National Park using line transect distance sampling. Transects were surveyed on three plains in the Park and the results compared with total counts conducted by the Department of Environment. Our estimate (109 onagers per 100 km2; 95% confidence interval 67–179) is similar to that obtained by the total counts (137 onagers per 100 km2). Distance sampling is therefore a promising method for estimating the abundance of the onager. Using the annual censuses performed by the Department of Environment over the last 13 years we estimated that the population has a growth rate of 0.09. During the same period the onager population in the Touran Protected Complex has experienced a severe decline. The high density of onagers within the National Park indicates the unsuitability of adjacent habitats, including Bahram-e-Goor Protected Area, for this species. Lack of sufficient security and poorly distributed water sources appear to be the main reasons discouraging onagers from entering the Bahram-e-Goor Protected Area. We recommend and describe management interventions that could potentially assist in maintaining the last surviving onager populations in Iran.

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White rhinoceros range size in the south-western Kruger National Park

Journal of Zoology ◽

10.1111/j.1469-7998.1993.tb02661.x ◽

1993 ◽

Vol 229 (4) ◽

pp. 641-649 ◽

Cited By ~ 8

Author(s):

D. J. Pienaar ◽

J. du P. Bothma ◽

G. K. Theron

Keyword(s):

National Park ◽

Range Size ◽

Kruger National Park ◽

The South ◽

White Rhinoceros

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Tendencias poblacionales recientes de la avutarda hubara en las Islas Canarias: análisis metodológico y estado de conservación

Animal Biodiversity and Conservation ◽

10.32800/abc.2012.35.0125 ◽

2012 ◽

Vol 35 (1) ◽

pp. 125-139

Author(s):

C. Schuster ◽

◽

J. J. Iglesias-Lebrija ◽

L. M. Carrascal ◽

◽

...

Keyword(s):

Canary Islands ◽

Conservation Status ◽

Distance Sampling ◽

Small Variation ◽

Population Trends ◽

Line Transect ◽

Sampling Area ◽

Average Value ◽

Houbara Bustard ◽

Population Sizes

Recent population trends of the houbara bustard in the Canary Islands. Methods and conservation status Determining conservation status requires rigorous and reliable data about population sizes and trends, especially if they have to be applied to islands where the species have small populations. The Canary bustard houbara (Chlamydotis undulata fuertaventurae) is catalogued as ‘in danger’ by the Red Book of the Birds of Spain. This work analyzes the value of previously published information on the species using the method of adjacent linear transects separated by 200 m, as a baseline for establishing robust population trends in 30 important areas (ranging from 1.3 to 12.8 km2) for the houbara in the islands of Lanzarote and Fuerteventura (Canary Islands). Censuses were repeated on the same dates (from November to December) and localities as those carried out in 1994, 2004 and 2006. The detection probability of the houbara was estimated by means of distance sampling, being 0.42 up to 250 m from the observer, and 0.82 in the main census belt of 100 m on either side of the line transect. The method of adjacent linear transects —counting the maximum number of hubaras detected— provides accurate figures of population densities (detection of 95.2% of the birds). The previous estimations of houbara densities can therefore be considered highly trustworthy, with a probable average underestimation of only 5 %. Nevertheless, the confidence intervals of density estimations using only one census were very large. Therefore, with only one census per sampling area and year it is not possible to obtain precise estimates of houbara densities with small variation around the average value. This raises concern when trying to obtain solid evidence about the increases–decreases of houbara populations comparing different dates or study areas. The density of the Canary Island hubara bustard decreased significantly from 2004/2006 to 2011 in eight areas of Fuerteventura (Vega Vieja, Los Alares–Pocetas, Matas Blancas, Lorenzo– Diviso, Corralejo, Lajares and Fimapaire) and in two areas of Lanzarote (Argana and La Santa). Conversely, the density of the houbara significantly increased in three areas of Lanzarote (Zonzamas, Guatiza and Llano de las Maretas). As a whole, average population density did not differ significantly between 2004/2006 and 2011 in Fuerteventura (slight decrease of 29% in 2011), but there was a significant increase in Lanzarote (increase of 60% from 2004/2006 to 2011). The change in density from 2004/2006 to 2011 tended to be an increase in areas further from paved roads, and a decrease in locations predominantly covered by loose sandy soils.

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