Elephant Database
African Elephant Specialist Group

Provisional African Elephant Population Estimates: update to 31 Dec 2013

All Years for Nigeria: 201620132007200219981995

Summary Totals for Nigeria

Estimates from SurveysGuesses% Known and
Possible Range
Area (km2)
Survey categoryEstimate± 95% CLFromTo
Aerial Total Counts00.00
Informed Guesses82027910.92,182
Degraded Data38038012.62,527
Totals 2015820380659  
Totals 20063480380480  
Assessed Range23.44,709
Unassessed Range76.615,379
Total Range10020,088

Summary Totals for Nigeria

Data Category Definite Probable Possible Speculative
Aerial or Ground Total Counts0000
Informed Guesses8200279
Other Guesses000380
Totals 20138200659
Totals 20063480105375

Interpretation of Changes in Estimates from Previous Report

 Estimates from SurveysGuessesArea
Cause of Change Estimate ± 95% CL From To% Known and PossibleTotal
Different Technique-26600+27910.92,182
Data Degraded000-1005.61,126

Interpretation of Changes in Estimates from Previous Report

Cause of Change Definite Probable Possible Speculative
Different Technique-26600+279
Data Degraded00-105+5

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

Cause of Change Definite Probable Possible Speculative
Different Technique-26600+279
Data Degraded00-105+5

Area of Range Covered by Each Data Category (km²)

Data CategoryKnown RangePossible RangeTotal Range
Informed Guesses2,18202,182
Other Guesses1,5161,0102,527
Unassessed Range8,1467,23315,379

Nigeria: Elephant Estimates

Cause ofSurvey Details2 Number of Elephants Area Map Location
Input ZoneChange1TypeReliab.YearEstimate95% C.L. SourcePFS3 (km²) Lon. Lat.
+ Andoni Island-OE20026 4*Mshelbwala et al., 20022215 7.5E 4.5N
-OE20026 4*Mshelbwala et al., 2002215 7.5E 4.5N
+ Chad Basin National Park-OE1994100Mshelbwala, 199812,160 14.4E 11.7N
-OE1994100Mshelbwala, 19982,160 14.4E 11.7N
+ Cross River National Park-DCE199874 56Obot et al., 19981239 9.2E 6.3N
-DCE199874 56Obot et al., 1998239 9.2E 6.3N
+ Gashaki Gumti-OE200220 30*R. Barnwell, pers. comm., 200215,860 11.7E 7.5N
-OE200220 30*R. Barnwell, pers. comm., 20025,860 11.7E 7.5N
+ Kambari-OE19985 10*Gawaisa, quest. reply, 199812,000 10.6E 8.8N
-OE19985 10*Gawaisa, quest. reply, 19982,000 10.6E 8.8N
+ Kwiambana Game Reserve-OE199380 40*Hurst, quest. reply, 199411,715 6.6E 11.3N
-OE199380 40*Hurst, quest. reply, 19941,715 6.6E 11.3N
+ Marguba Forest Reserve-ATA20060Omondi et al., 20062710 12.7E 11.5N
-ATA20060Omondi et al., 2006710 12.7E 11.5N
+ Okomu Game Santuary-OE199140NRCC, 199121,082 5.1E 6.3N
-OE199140NRCC, 19911,082 5.1E 6.3N
+ Omo Forest Reserve-OE199430 20*Mshelbwala, 199821,300 3.6E 6.8N
-OE199430 20*Mshelbwala, 19981,300 3.6E 6.8N
+ Sambisa-ATA20060Omondi et al., 20062647 13.4E 11.3N
-ATA20060Omondi et al., 2006647 13.4E 11.3N
+ Taylor Creek-OE199325Thouless, 19932145 6.4E 5.2N
-OE199325Thouless, 1993145 6.4E 5.2N
+ Yankari National ParkDTOD201182 279*Bergl et al., 201112,244 10.4E 9.8N
DTOD201182 279*Bergl et al., 20112,244 10.4E 9.8N

* 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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