Estimating population sizes for elusive animals: the forest elephants of Kakum National Park, Ghana

Eggert, L. S.; Eggert, J. A.; Woodruff, D. S.

doi:10.1046/j.1365-294x.2003.01822.x

Cited by 243 publications

(234 citation statements)

References 58 publications

(72 reference statements)

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“…The advent of permanent marking techniques such as genetic 'tagging' (e.g. Feldheim et al 2002, Mowat & Paetkau 2002, Eggert et al 2003 for whale sharks will permit validation of our model predictions.…”

Section: Discussionmentioning

confidence: 99%

Population size and structure of whale sharks Rhincodon typus at Ningaloo Reef, Western Australia

Meekan¹,

Bradshaw²,

Press³

et al. 2006

Mar. Ecol. Prog. Ser.

165

222

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We used photo-identification to produce estimates of population size and structure of whale sharks Rhincodon typus at Ningaloo Reef, Western Australia. We analysed photographs of whale sharks taken from 1992 to 2004. A combination of spot and stripe patterns behind the last gill slit and forward of the dorsal fin (lateral view), and distinctive scars and marks on the body and fins were useful for identifying individual sharks. These patterns appeared to be unique to individuals and distinctive markings could be recognized on some sharks for more than a decade. From 581 photographs, 159 individuals were identified. Of these, 74% were male, 16% were female and 10% were of indeterminate gender. Photographed sharks ranged in estimated size from 3 to 10 m total length (TL). The size distribution of sharks was bimodal with a large peak at 8 m and a smaller peak at 6 m TL. Sixty individuals were resighted during the study. Of these, 46 were resighted at different times during the same year (sometimes on multiple occasions) up to 4 mo after they were initially photographed, and 33 were resighted (4 on > 2 occasions) in different years. The interval between inter-annual resightings was typically 1 to 3 yr; however, 2 sharks were resighted after a period of 12 yr. We estimated the super population of whale sharks that visit Ningaloo Reef to consist of approximately 300 to 500 individuals (95% confidence interval) based on closed population models, or 320 to 440 based on Jolly-Seber open-population models. Our study shows that photo-identification offers a practical, non-invasive and non-destructive means to obtain data on the population size and demography of whale sharks.

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Section: Discussionmentioning

confidence: 99%

Population size and structure of whale sharks Rhincodon typus at Ningaloo Reef, Western Australia

Meekan¹,

Bradshaw²,

Press³

et al. 2006

Mar. Ecol. Prog. Ser.

165

222

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“…In addition, traditional CMR methods that require trapping or handling of individuals may harm the animals. For difficult-to-observe species, noninvasive genetic surveys have in recent years provided valuable information for the management and monitoring of populations [7][8][9][10][11][12][13]. These studies showed that use of molecular census techniques may reduce time and effort and provide more detailed information about elusive species [14].…”

mentioning

confidence: 99%

Noninvasive genetic assessment of the population trend and sex ratio of the Shennongjia population of Sichuan snub-nosed monkeys (Rhinopithecus roxellana)

Chang

Liu

Yang³

et al. 2011

Chin. Sci. Bull.

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Effective population management relies on assessments of population size and sex ratio. However, these estimates are difficult to obtain for elusive and rare species. Recently, noninvasive genetic census methods have been developed as an alternative to traditional capture-mark-recapture methods. In this study, we estimated the size of the Sichuan snub-nosed monkey (Rhinopithecus roxellana) population in the Shennongjia Nature Reserve (SNR) using a noninvasive sampling method based on 16 microsatellite loci. We also used a PCR-based genetic method to sex the sampled individuals and infer the population sex ratio. The population size of R. roxellana in the SNR was estimated to be 1044 individuals (95% CI TIRM : 613-1409). The estimated population sex ratio is more female-biased than expected, which we attribute to the sampling biased towards one male units and limited sampling of bachelor male units. Moreover, there is no suggestion that the heavy traffic road through the reserve might block movement of monkeys. The results of this study indicate genetic assessments based on a noninvasive sampling method can provide useful information regarding populations of elusive primates.

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“…The method can easily be up-scaled to larger mammals like elephants, 27 tigers and hornbills 28 of conventional concern to Thai conservationists. This would provide wildlife managers with a new tool to assess a population' s viability and opens up numerous research opportunities, as habitat fragmentation is such a ubiquitous phenomenon.…”

Section: Discussionmentioning

confidence: 99%

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Srikwan¹,

Hufford²,

Eggert³

et al. 2002

ScienceAsia

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We describe the sequences of six primer pairs for the PCR amplification of nuclear microsatellite markers in the tree shrews, Tupaia glis and T. belangeri. Multilocus genotyping based on non-destructive DNA sampling of live-trapped animals reveals high allelic variability (A) and heterozygosity (H e ) at these loci. Such characteristics make these genetic markers ideal for linkage mapping and comparative genomics, and for studies of pedigree relationships, population structure, and population genetic variability in wild populations. We illustrate another use of these markers in the study of genetic erosion in small recently fragmented natural populations of tree shrews in south Thailand. This method for detecting and monitoring genetic erosion in fragmented populations can be applied to larger taxa of traditional concern to wildlife managers.

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Estimating population sizes for elusive animals: the forest elephants of Kakum National Park, Ghana

Cited by 243 publications

References 58 publications

Population size and structure of whale sharks Rhincodon typus at Ningaloo Reef, Western Australia

Population size and structure of whale sharks Rhincodon typus at Ningaloo Reef, Western Australia

Noninvasive genetic assessment of the population trend and sex ratio of the Shennongjia population of Sichuan snub-nosed monkeys (Rhinopithecus roxellana)

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