Elephant Database
African Elephant Specialist Group

Gabon
Provisional African Elephant Population Estimates: update to 31 Dec 2013

  1. Reports
  2. 2013
  3. Africa
  4. Central Africa
  5. Gabon

All Years for Gabon: 2016 — 2013 — 2007 — 2002 — 1998 — 1995

Summary Totals for Gabon

Estimates from SurveysGuesses% Known and
Possible Range		Area (km2)
Survey categoryEstimate± 95% CLFromTo
Reliable Dung Counts5,9212,302——4.910,386
Other Dung Counts0—15,65517,8832.65,441
Informed Guesses337—6,80911,48613.829,478
Degraded Data——4,0354,0351.94,128
Modeled Extrapolation——32,37832,37876.7163,629
Totals 20156,2582,30258,87765,782  
Totals 20062,350827217,359218,646  
Assessed Range99.9213,062
Unassessed Range0.1311
Total Range100213,373

Summary Totals for Gabon

Data Category Definite Probable Possible Speculative
Direct Sample Counts and Reliable Dung Counts3,6192,3022,3020
Other Dung Counts012,0714,6630
Informed Guesses337039,1874,677
Other Guesses0004,035
Totals 20133,95614,37346,1528,712
Totals 20061,52323,45727,911168,739

Interpretation of Changes in Estimates from Previous Report

 Estimates from SurveysGuessesArea
Cause of Change Estimate ± 95% CL From To% Known and PossibleTotal
Repeat Survey+1,792±2,320002.24,669
New Population+3370-167,806-167,4700.71,570
Different Technique+1,343±778-168,890-168,8901.94,159
Different Area00+1,318+3,2281.83,890
New Guess+4360-158,541-145,99491.0194,243
Data Degraded00001.94,128
Totals+3,908±2,447-493,919-479,12699.7212,658

Interpretation of Changes in Estimates from Previous Report

Cause of Change Definite Probable Possible Speculative
Repeat Survey+452+1,340+1,3400
New Population+3370-36-16,441
Different Technique+565+2,141-1,327-16,777
Different Area0+2,273+3830
New Guess0-20,634+22,357-4,230
Data Degraded00-4,035+4,035
Totals+1,354-14,880+18,681-33,413

Interpretation of Changes in Estimates from Previous Report (2007 scaling)

Cause of Change Definite Probable Possible Speculative
Repeat Survey+813+1,437+1,2980
New Population+6060-35-74,227
Different Technique+1,015+2,296-1,285-75,744
Different Area0+2,438+3710
New Guess0-22,130+21,653-19,097
Data Degraded00-3,908+18,217
Totals+2,433-15,959+18,093-150,852
toggle scaling

Area of Range Covered by Each Data Category (km²)

Data CategoryKnown RangePossible RangeTotal Range
Direct Sample Counts and Reliable Dung Counts10,2899710,386
Informed Guesses47,267145,841193,107
Other Dung Counts5,3421005,441
Other Guesses3,5555734,128
Unassessed Range932-621311
Totals67,384145,988213,373

Gabon: Elephant Estimates

Cause ofSurvey Details2 Number of Elephants Area Map Location
Input ZoneChange1TypeReliab.YearEstimate95% C.L. SourcePFS3 (km²) Lon. Lat.
+ Djouah Bélinga-OE20024,035Lahm & Barnes, pers. comm., 200624,339 13.6E 1.2N
-OE20024,035Lahm & Barnes, pers. comm., 20064,339 13.6E 1.2N
+ Evaro ZoneNGOD2006469 525*Maisels & Strindberg, 201222,365 10.0E 0.9S
NGOD2006469 525*Maisels & Strindberg, 20122,365 10.0E 0.9S
+ Gamba Reserve ComplexNGOD20112,020Ngoran, pers. comm., 201424,456 10.4E 2.4S
NGOD20081,328Blake et al., 20122,337 10.0E 2.2S
NGDCD2007442Maisels & Strindberg, 20121,510 9.6E 2.2S
NGOD2011250 100*Ngoran, pers. comm., 2014609 10.4E 2.4S
+ Ivindo National ParkDADCC20093,489732Maisels et al., 201023,864 12.6E 0.1N
DADCC20092,851 677Maisels et al., 20102,996 12.6E 0.1N
DADCC2009638 278Maisels et al., 2010868 12.6E 0.1N
+ Lopé National ParkRSDCB20094,142 2,167Bezangoye & Maisels, 201024,486 11.5E 0.6S
RSDCB20094,142 2,167Bezangoye & Maisels, 20104,486 11.5E 0.6S
+ Lopé-Waka CorridorDTDCB20081,343 778Maisels et al., 200823,000 11.3E 1.1S
DTDCB20081,343 778Maisels et al., 20083,000 11.3E 1.1S
+ Mayombe Ecosystem NGDCB2011436Aba'a et al., 201151,682 11.1E 3.5S
NGDCB2011436Aba'a et al., 20111,682 11.1E 3.5S
+ Mayumba National Park NGOD201160 68*Maisels & Strindberg, 20123161 11.0E 3.8S
NGOD201160 68*Maisels & Strindberg, 2012161 11.0E 3.8S
+ Minkébé National ParkNGDCC20136,875 4,588ANPN, 2013111,956 12.6E 1.7N
NGDCC20136,875 4,588ANPN, 201311,956 12.6E 1.7N
+ Monts de Cristal Ecosystem NGOD20062,416 2,707*Maisels & Strindberg, 201225,300 10.3E 0.7N
NGOD20062,416 2,707*Maisels & Strindberg, 20125,300 10.3E 0.7N
+ Mwagné Buffer NGOD2004151 168*Maisels & Strindberg, 201222,020 13.7E 0.7N
NGOD2004151 168*Maisels & Strindberg, 20122,020 13.7E 0.7N
+ Mwagné National ParkDTDCC20121,363 378Maisels & Akou, 2012.31,166 13.8E 0.5N
DTDCC20121,363 378Maisels & Akou, 2012.1,166 13.8E 0.5N
+ Plateaux Batéké National ParkNPOD2006301 336*Maisels & Strindberg, 2012; Douckaga, 201422,042 12.5E 0.5S
NPOD2006301 336*Maisels & Strindberg, 2012; Douckaga, 20142,042 12.5E 0.5S
+ Pongara National Park-DCC2006344 194Latour, 20063378 9.4E 0.1N
-DCC2006344 194Latour, 2006378 9.4E 0.1N
+ Rest of Gabon Forest RangeNGOD201132,378Maisels, Strindberg et al., 20131145,497 11.1E 0.4S
NGOD201132,378Maisels, Strindberg et al., 2013145,497 11.1E 0.4S
+ Waka National ParkNGOD2006690 773*Maisels & Strindberg, 201221,061 11.1E 1.3S
NGOD2006690 773*Maisels & Strindberg, 20121,061 11.1E 1.3S
+ Wonga-Wongue Presidential Reserve NGDCD20111,039Motsaba & Aba'a 201224,967 9.5E 0.5S
NGDCD20111,039Motsaba & Aba'a 20124,967 9.5E 0.5S

* Range of informed guess

1Key to Causes of Change (only tracked since 2007): DA: Different Area; DD: Data Degraded; DT: Different Technique; NA: New Analysis; NG: New Guess; NP: New population; PL: Population Lost; RS: Repeat Survey (RS ́ denotes a repeat survey that is not statistically comparable for reasons such as different season); –––: No Change

2Key to Survey Types: AC: Aerial Count, not specified; AS: Aerial Sample Count; AT: Aerial Total Count; DC: Dung Count; EX: Extrapolation from GIS; GD: Genetic Dung Count; GS: Ground Sample Count; GT: Ground Total Count; IG: Informed Guess; IR: Individual Registration; OG: Other Guess. Survey Type is followed by an indicator of survey quality, ranked from 1 to 3 (best to worst). Survey Reliability is keyed A-E (best to worst) as outlined in this table.

3PFS: Priority for Future Surveys, ranked from 1 to 5 (highest to lowest). Based on the precision of estimates and the proportion of national range accounted for by the site in question, PFS is a measure of the importance and urgency for future population surveys. All areas of unassessed range have a priority of 1. See Introduction for details on how the PFS is derived.

Note that totals for the Definite, Probable, and Possible categories are derived by pooling the variances of individual estimates, as described at http://www.africanelephantdatabase.org/reliability. As a result, totals do not necessarily match the simple sum of the entries within a given category.

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