First assessment of age and sex structures of elephants by using dung size analysis in a West African savannah
DOI:
https://doi.org/10.1515/eje-2017-0001Keywords:
African Elephant, Age structure, sex ratio, dung circumference analysis, Burkina FasoAbstract
1. An age and sex structure study of the West African savannah elephant (Loxodonta africana africana) population of the Nazinga Game ranch (Burkina Faso) was carried out using direct sightings of individuals near water points, where they group during hot periods of the day, and droppings circumference measurements of dung pile along line transects, during the dry seasons of 2007 and 2008. The age structure, from direct observation data, was estimated by classifying the individuals into 9 age-class-categories based on body size and eruption (length) of tusks.
2. The frequency distribution of number of individuals into the age-class-categories showed high similarity with the distribution of circumference measurements of dung-piles that the individuals were seen depositing. Fifty dung-piles measured soon after they were deposited (Class A) and after they dried (to class C) showed a significant difference between the circumference measurements in relation to the time elapsed between the measurements.
3. The frequency distribution of dung circumference classes of the observed elephants was similar to that of the dung-piles measured along the transects in 2008. Therefore, dung-piles measurements were used to estimate the Nazinga Game Ranch savanna elephant population’s age and sex structures at the end of dry seasons of 2007 and 2008. We advocated that the Nazinga elephant population consisted mainly of sub-adults.
4. The sex ratio was estimated to be in favour of females (1/2). The age-class-specific sex ratio was uneven for calves and young individuals, while being in favour of females with adults. Individuals of less than 1 year represented 6% of the population during the study period.
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USA, 101 p.
Barnes, R.F.W., Asamoah-BoatEng, B., Naada Majam, J. & Agyei-Ohmemeng,
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dung-piles in the forests of southern Ghana. Afr. J. Ecol.
35, 39–52.
Barnes, R.F.W., (2001) How reliable are dung counts for estimating elephant
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Blanc, J.J., Barnes, RF.W., Craig, G.C., Dublin, H.T., Thouless, C.R., Douglas-
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West African Savannahs? PLoS ONE 36,6, e20619.
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report, Ouagadougou, Burkina Faso.
Coe, M. (1974) Defaecation by African elephants (Loxodonta africana africana
(Blumenbach)). East African Wildlife Journal, 10, 165–174.
Corfield, T.F. (1973) Elephant Mortality in Tsavo National Park, Kenya.
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Croze, H. (1972) A modifi ed photogrammetric technique for assessing
age-structure of elephant populations and its uses in Kidepo National
Park. East African Wildlife Journal, 10, 91–115.
Damiba, T.E. & Ables, E.D. (1994) Population characteristics and impacts
on woody vegetation of elephants on Nazinga Game Ranch,
Burkina Faso. Pachyderm, 18, 46–53.
Douglas-Hamilton, I. (1973) On the ecology and behaviour of the Lake
Manyara elephants. East African Wildlife Journal, 11, 401–403.
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Forest Elephants to Infer Population Structure, Movements,
and Habitat Use in a Conservation and Development Landscape
in Gabon. Conservation Biology, 1, 107–18.
Filippi, E., Rugiero, L., Capula, M., Burke, R.L. &Luiselli, L. (2010) Population
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9, 54–60.
Galimberti, F., Sanvito, S., Boitani, L. & Fabiani, A. (2001) Viability of the
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de l’Environnement et du Tourisme, Direction de l’Aménagement
Forestier et du Reboisement, Ouagadougou, Burkina Faso.
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Hailey, A., Wright, J. & Steer, E. (1988) Population ecology and conservation
of tortoises: the effects of disturbance. Herpetological Journal,
1, 294–301.
Hammond, P.S., Mizroch, S.A. & Donovan, G.P. (1990) Individual Recognition
of Cetaceans: Use of Photo-Identification and Other
Techniques to Estimate Population Parameters. Report of the
International Whaling Commission Special Issue 12. Cambridge.
Hema, M.E., Niagabaré, B., Zongo, J.P. & Hébié, L. (2009) Recensements
pédestres des grands mammifères diurnes aux Ranch de Gibier
de Nazinga. Unpublished report, Ranch de Gibier de Nazinga,
Section Suivi Ecologique et Recherche Appliquée.
Hema, M.E., Barnes, R.F.W. & Guenda, W. (2010a) Distribution of savannah
elephants (Loxodonta africana africana Blumenbach 1797)
within Nazinga game ranch, southern Burkina Faso. African Journal
of Ecology, 49, 141–149.
Hema, M.E., Barnes, R.F.W. & Guenda, W. (2010b) The seasonal distribution
of savana elephants (Loxodonta africana africana Blumenbach
1797) in Nazinga Game Ranch, southern Burkina Faso.
Pachyderm, 48, 33–40.
Hema, M.E. (2012) Distribution et impact environnemental de
l’elephant de savana: distributions de l’elephant et impact sur
l’environnement du ranch de gibier de Nazinga, Burkina Faso.
Presse Academique Francophone, Montreal.
Hosmer, D.W. & Lemeshow, S. (2000) Applied logistic regression analysis.
2nd ed. John Wiley and Sons, New York.
Jachmann, H. & Bell, R.H.V. (1984) The use of éléphant droppings in assessing
numbers, occupance and âge structure: a refinement of
the method. African Journal of Ecology 22, 127–141.
Kioko, J., Zink, E., Sawdy, M. & Kiffner, C. (2013) Elephant (Loxodonta
africana) demography and behaviour in the Tarangire-Manyara
Ecosystem, Tanzania. South African Journal of Wildlife Research,
43(1), 44–51.
Laws, R.M. (1966) Age criteria for the African elephant, Loxodonta a.
africana. East African Wildlife Journal, 4, 1–31.
Laws, R.M. (1969) The Tsavo research project. Journal of reproduction
and fertility (Suppl.), 6, 495–531.
Laws, R.M., Parker, I.S.C. & Johnstone, R.C.B. (1975) “Elephants and
their Habitats.” Clarendon Press, Oxford.
Lee, P.C. & Moss, C.J. (1995) Statural growth in known-age African elephants
(Loxodonta africana). Journal Zoology, 236, 29–41.
Leuthold, W. (1976) Age structure of elephants in Tsavo National Park,
Kenya. Journal of Applied Ecology, 13, 435–444.
Lindeque, M. (1991) Dentition and age estimation of elephants in the
Etosha National Park, Namibia. Madoqua, 18(1), 17–25.
McCullagh, P. & Nelder, J.A. (1989) Generalized linear models. Chapman
and Hall/CRC, London, U.K.
Morrison, T.A., Chiyo, P.I., Moss, C.J. & Albert, S.C. (2005) Measures of
dung bolus size for known-age African elephants (Loxodonta africana):
implications for age estimation. Journal of Zoology, 266,
89–94.
Moss, C.J. (1983) Oestrous behaviour and female choice in the African
elephant. Behaviour, 86, 167–196.
Moss, C.J. (1996) Getting to know a population. In Studying elephants
Kanwanga K, 1996 pp. 58–74. Eds. Nairobi, Kenya: African Wildlife
Foundation.
Moss, C.J. (2001) The demography of an African elephant (Loxodonta
Africana) population in Amboseli, Kenya. Journal of Zoology,
255, 145–156.
Nussey, D.H., Coulson, T., Festa-Bianchet, M. & Gaillard, J.M. (2008)
Measuring senescence in wild animal populations: towards a
longitudinal approach. Functional Ecology, 22, 393–406.
Poole, J.H. (1989a) Mate guarding, reproductive success and female
choice in African elephants. Animal Behaviour, 37, 842–849.
Poole, J.H. (1989b) Announcing intent: the aggressive state of musth in
African elephants. Animal Behaviour, 37, 140–152.
Postma, M., Tordiffe, A. S. W., Hofmeyr, M. S., Reisinger, R. R., Bester,
L. C., Buss, P. E. & de Bruyn, P. J. N. (2015) Terrestrial mammal
three-dimensional photogrammetry: multispecies mass estimation.
Ecosphere, 6(12), 1–16.
Reilly, J. (2002) Growth in the Sumatran elephant (Elephas maximus Sumatrans)
and age estimation based on dung diameter. Journal of
Zoology, 258, 205–213.
Sebogo, L. (1986) Structure d’âge des éléphants au ranch de Gibier de
Nazinga. Université de Ouagadougou. Mémoire d‟Ingénieur des
Techniques du Développement Rural, Université de Ouagadougou.
Skalski, J.R., Ryding, K.E. & Millspaugh, J. (2005) Wildlife Demography:
Analysis of Sex, Age, and Count Data. Elesevier academic press;
San Diego.
Sokal, R.R. & Rohlf, F.J. (2014) Biometry, 4th edition. W.H. Freeman &
Company, New York.
Stansfield, F.J. (2015) A Novel Objective Method of Estimating the Age
of Mandibles from African Elephants (Loxodonta africana Africana).
PLoS ONE 10(5), e0124980.
Sukumar, R. (1992) The Asian elephant, ecology and management.
Cambridge University press.
Wittemyer, G., Daballen, D. & Douglas-Hamilton, I. (2013) Comparative
Demography of an at-Risk African Elephant Population. PLoS
ONE 8(1), e53726.
White, L.J.T. (1995) Factors affecting the duration of elephant dung
piles in rain forest in the Lopé Reserve. Gabon. Afr. J. Ecol., 33,
142–150.
Whyte, I.J. (1996) Collecting data from dead elephants, pages 171-178.
In K. Kangwana (ed.). Studying elephants. AWF Tech. Handbook
Series No. 7. African Wildlife Foundation
Asian elephant populations: a comparison of two field methods
of age estimation. Gajah 29, 11–16.
Barnes, R.F.W. (1982) Elephant feeding behaviour in Ruaha National
Park. Afr. J. Ecol. 20, 123–136.
Barnes, R.F.W. & Jensen, K.L. (1987) How to count elephants in forests.
IUCN African Éléphant and Rhino Specialist Group Technical Bulletin
1, 1–6.
Barnes, R.F.W., Asamoah-Boateng, B., Naada Majam, J., Agyei-Ohmemeng,
J., Tchamba, M.N., Ekobo, A. & Nchandji, A.C. (1994) Improving
the accuracy of forest elephant census methods: study
of dung decay rates in Ghana and Cameroon. Wild. Cons. Soc.
USA, 101 p.
Barnes, R.F.W., Asamoah-BoatEng, B., Naada Majam, J. & Agyei-Ohmemeng,
J. (1997) Rainfall and the population dynamics of elephant
dung-piles in the forests of southern Ghana. Afr. J. Ecol.
35, 39–52.
Barnes, R.F.W., (2001) How reliable are dung counts for estimating elephant
numbers? Afr. J. Ecol., 39, 1–9.
Blanc, J.J., Barnes, RF.W., Craig, G.C., Dublin, H.T., Thouless, C.R., Douglas-
Hamilton, I. & Hart, J.A. (2007) African Elephant Status Report
2007: an update from the African Elephant Database. Occasional
Paper Series of the IUCN Species Survival Commission, No.
33. IUCN/SSC African Elephant Specialist Group. IUCN, Gland,
Switzerland.
Bouché, P., Douglas-Hamilton, I., Wittemyer, G., Nianogo, A.J., Doucet,
J.L. & Lejeune, P. (2011) Will Elephants Soon Disappear from
West African Savannahs? PLoS ONE 36,6, e20619.
Bouché, P. (2012) Recensement pédestre des grands mammifères de la
Foret Classée et Ranch de Gibier de Nazinga, Burkina Faso. OFINAP
report, Ouagadougou, Burkina Faso.
Coe, M. (1974) Defaecation by African elephants (Loxodonta africana africana
(Blumenbach)). East African Wildlife Journal, 10, 165–174.
Corfield, T.F. (1973) Elephant Mortality in Tsavo National Park, Kenya.
East African Wildlife Journal, 11, 339–368.
Croze, H. (1972) A modifi ed photogrammetric technique for assessing
age-structure of elephant populations and its uses in Kidepo National
Park. East African Wildlife Journal, 10, 91–115.
Damiba, T.E. & Ables, E.D. (1994) Population characteristics and impacts
on woody vegetation of elephants on Nazinga Game Ranch,
Burkina Faso. Pachyderm, 18, 46–53.
Douglas-Hamilton, I. (1973) On the ecology and behaviour of the Lake
Manyara elephants. East African Wildlife Journal, 11, 401–403.
Dublin, H.T. & Taylor, R.D. (1996) Making management decisions from
data. AWF Technical handbook, 7, 10–17.
Eggert, L.S., Buij, R., Lee, M.E., Campbell, P., Dallmeier, F., Fleischer, R.C.,
Alonso, A & Maldonado J.E. (2013) Using Genetic Profiles of African
Forest Elephants to Infer Population Structure, Movements,
and Habitat Use in a Conservation and Development Landscape
in Gabon. Conservation Biology, 1, 107–18.
Filippi, E., Rugiero, L., Capula, M., Burke, R.L. &Luiselli, L. (2010) Population
and thermal ecology of Testudo hermanni hermanni in the
Tolfa Mountains of Central Italy. Chelonian Conservation and Biology,
9, 54–60.
Galimberti, F., Sanvito, S., Boitani, L. & Fabiani, A. (2001) Viability of the
southern elephant seal population of the Falkland Islands. Animal
Conservation, 4, 81–88.
Guinko, S. (1984) Végétation de la Haute-Volta. Thèse d’Etat, Sciences
Naturelles, Université de Bordeau, France.
Guinko, S. (1985) La végétation et la flore du Burkina Faso. Ministère
de l’Environnement et du Tourisme, Direction de l’Aménagement
Forestier et du Reboisement, Ouagadougou, Burkina Faso.
Guy, P.R. (1975) The daily food intake of the African elephant, Loxodonta
africana Blumenbach, in Rhodesia. Arnoldia, 7, 1–8.
Hailey, A., Wright, J. & Steer, E. (1988) Population ecology and conservation
of tortoises: the effects of disturbance. Herpetological Journal,
1, 294–301.
Hammond, P.S., Mizroch, S.A. & Donovan, G.P. (1990) Individual Recognition
of Cetaceans: Use of Photo-Identification and Other
Techniques to Estimate Population Parameters. Report of the
International Whaling Commission Special Issue 12. Cambridge.
Hema, M.E., Niagabaré, B., Zongo, J.P. & Hébié, L. (2009) Recensements
pédestres des grands mammifères diurnes aux Ranch de Gibier
de Nazinga. Unpublished report, Ranch de Gibier de Nazinga,
Section Suivi Ecologique et Recherche Appliquée.
Hema, M.E., Barnes, R.F.W. & Guenda, W. (2010a) Distribution of savannah
elephants (Loxodonta africana africana Blumenbach 1797)
within Nazinga game ranch, southern Burkina Faso. African Journal
of Ecology, 49, 141–149.
Hema, M.E., Barnes, R.F.W. & Guenda, W. (2010b) The seasonal distribution
of savana elephants (Loxodonta africana africana Blumenbach
1797) in Nazinga Game Ranch, southern Burkina Faso.
Pachyderm, 48, 33–40.
Hema, M.E. (2012) Distribution et impact environnemental de
l’elephant de savana: distributions de l’elephant et impact sur
l’environnement du ranch de gibier de Nazinga, Burkina Faso.
Presse Academique Francophone, Montreal.
Hosmer, D.W. & Lemeshow, S. (2000) Applied logistic regression analysis.
2nd ed. John Wiley and Sons, New York.
Jachmann, H. & Bell, R.H.V. (1984) The use of éléphant droppings in assessing
numbers, occupance and âge structure: a refinement of
the method. African Journal of Ecology 22, 127–141.
Kioko, J., Zink, E., Sawdy, M. & Kiffner, C. (2013) Elephant (Loxodonta
africana) demography and behaviour in the Tarangire-Manyara
Ecosystem, Tanzania. South African Journal of Wildlife Research,
43(1), 44–51.
Laws, R.M. (1966) Age criteria for the African elephant, Loxodonta a.
africana. East African Wildlife Journal, 4, 1–31.
Laws, R.M. (1969) The Tsavo research project. Journal of reproduction
and fertility (Suppl.), 6, 495–531.
Laws, R.M., Parker, I.S.C. & Johnstone, R.C.B. (1975) “Elephants and
their Habitats.” Clarendon Press, Oxford.
Lee, P.C. & Moss, C.J. (1995) Statural growth in known-age African elephants
(Loxodonta africana). Journal Zoology, 236, 29–41.
Leuthold, W. (1976) Age structure of elephants in Tsavo National Park,
Kenya. Journal of Applied Ecology, 13, 435–444.
Lindeque, M. (1991) Dentition and age estimation of elephants in the
Etosha National Park, Namibia. Madoqua, 18(1), 17–25.
McCullagh, P. & Nelder, J.A. (1989) Generalized linear models. Chapman
and Hall/CRC, London, U.K.
Morrison, T.A., Chiyo, P.I., Moss, C.J. & Albert, S.C. (2005) Measures of
dung bolus size for known-age African elephants (Loxodonta africana):
implications for age estimation. Journal of Zoology, 266,
89–94.
Moss, C.J. (1983) Oestrous behaviour and female choice in the African
elephant. Behaviour, 86, 167–196.
Moss, C.J. (1996) Getting to know a population. In Studying elephants
Kanwanga K, 1996 pp. 58–74. Eds. Nairobi, Kenya: African Wildlife
Foundation.
Moss, C.J. (2001) The demography of an African elephant (Loxodonta
Africana) population in Amboseli, Kenya. Journal of Zoology,
255, 145–156.
Nussey, D.H., Coulson, T., Festa-Bianchet, M. & Gaillard, J.M. (2008)
Measuring senescence in wild animal populations: towards a
longitudinal approach. Functional Ecology, 22, 393–406.
Poole, J.H. (1989a) Mate guarding, reproductive success and female
choice in African elephants. Animal Behaviour, 37, 842–849.
Poole, J.H. (1989b) Announcing intent: the aggressive state of musth in
African elephants. Animal Behaviour, 37, 140–152.
Postma, M., Tordiffe, A. S. W., Hofmeyr, M. S., Reisinger, R. R., Bester,
L. C., Buss, P. E. & de Bruyn, P. J. N. (2015) Terrestrial mammal
three-dimensional photogrammetry: multispecies mass estimation.
Ecosphere, 6(12), 1–16.
Reilly, J. (2002) Growth in the Sumatran elephant (Elephas maximus Sumatrans)
and age estimation based on dung diameter. Journal of
Zoology, 258, 205–213.
Sebogo, L. (1986) Structure d’âge des éléphants au ranch de Gibier de
Nazinga. Université de Ouagadougou. Mémoire d‟Ingénieur des
Techniques du Développement Rural, Université de Ouagadougou.
Skalski, J.R., Ryding, K.E. & Millspaugh, J. (2005) Wildlife Demography:
Analysis of Sex, Age, and Count Data. Elesevier academic press;
San Diego.
Sokal, R.R. & Rohlf, F.J. (2014) Biometry, 4th edition. W.H. Freeman &
Company, New York.
Stansfield, F.J. (2015) A Novel Objective Method of Estimating the Age
of Mandibles from African Elephants (Loxodonta africana Africana).
PLoS ONE 10(5), e0124980.
Sukumar, R. (1992) The Asian elephant, ecology and management.
Cambridge University press.
Wittemyer, G., Daballen, D. & Douglas-Hamilton, I. (2013) Comparative
Demography of an at-Risk African Elephant Population. PLoS
ONE 8(1), e53726.
White, L.J.T. (1995) Factors affecting the duration of elephant dung
piles in rain forest in the Lopé Reserve. Gabon. Afr. J. Ecol., 33,
142–150.
Whyte, I.J. (1996) Collecting data from dead elephants, pages 171-178.
In K. Kangwana (ed.). Studying elephants. AWF Tech. Handbook
Series No. 7. African Wildlife Foundation
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How to Cite
Hema, E. M., Di Vittorio, M., Petrozzi, F., Luiselli, L., & Guenda, W. (2017). First assessment of age and sex structures of elephants by using dung size analysis in a West African savannah. European Journal of Ecology, 3(1), 1-8. https://doi.org/10.1515/eje-2017-0001
