Elephant Database
African Elephant Specialist Group

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

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

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

Summary Totals for Chad

Estimates from SurveysGuesses% Known and
Possible Range		Area (km2)
Survey categoryEstimate± 95% CLFromTo
Aerial Total Counts454———5.03,101
Informed Guesses433—1821430.418,668
Other Guesses——0134.02,433
Totals 2015887018227  
Totals 20063,88501,5001,950  
Assessed Range39.424,202
Unassessed Range60.637,288
Total Range10061,490

Summary Totals for Chad

Data Category Definite Probable Possible Speculative
Aerial or Ground Total Counts454000
Informed Guesses433018196
Other Guesses7000
Totals 2013894018196
Totals 20063,88501,500450

Interpretation of Changes in Estimates from Previous Report

 Estimates from SurveysGuessesArea
Cause of Change Estimate ± 95% CL From To% Known and PossibleTotal
Repeat Survey-3,4310005.03,101
New Population+9600+237.54,604
New Guess+3370-1,482-1,74626.816,497
Totals-2,9980-1,482-1,72339.424,202

Interpretation of Changes in Estimates from Previous Report

Cause of Change Definite Probable Possible Speculative
Repeat Survey-3,431000
New Population+10300+10
New Guess+3370-1,482-264
Totals-2,9910-1,482-254

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

Cause of Change Definite Probable Possible Speculative
Repeat Survey-3,431000
New Population+10300+10
New Guess+3370-1,482-264
Totals-2,9910-1,482-254
toggle scaling

Area of Range Covered by Each Data Category (km²)

Data CategoryKnown RangePossible RangeTotal Range
Aerial or Ground Total Counts3,10103,101
Informed Guesses18,668018,668
Other Guesses1,6597742,433
Unassessed Range29,9517,33837,288
Totals53,3788,11261,490

Chad: Elephant Estimates

Cause ofSurvey Details2 Number of Elephants Area Map Location
Input ZoneChange1TypeReliab.YearEstimate95% C.L. SourcePFS3 (km²) Lon. Lat.
+ Baga Sola AreaNPOD20136African Parks, 20132963 18.7E 13.1N
NPOD20136African Parks, 2013963 18.7E 13.1N
+ Baibokoum - Mbitoye AreaNGOD201330African Parks, 201316,052 17.8E 12.2N
NGOD201330African Parks, 20136,052 17.8E 12.2N
+ Binder Lere Faunal ReserveNPOD201390 10*African Parks, 201322,533 18.6E 12.0N
NPOD201390 10*African Parks, 20132,533 18.6E 12.0N
+ Birket Fatime - Eref AreaNPOE20137 13*African Parks, 201321,884 18.6E 13.2N
NPOE20137 13*African Parks, 20131,884 18.6E 13.2N
+ Bousso - Mbere AreaNGOD2013171 179*African Parks, 201314,570 18.6E 13.2N
NGOD2013171 179*African Parks, 20134,570 18.6E 13.2N
+ Dembo AreaNGOE20090African Parks, 201322,409 18.1E 8.1N
NGOE20090African Parks, 20132,409 18.1E 8.1N
+ Gagal-Yapala (Kamkel) AreaNGOD201318African Parks, 20132891 15.4E 9.1N
NGOD201318African Parks, 2013891 15.4E 9.1N
+ Koloudia-Doum Doum AreaNGOD201363 7*African Parks, 201322,363 15.3E 13.4N
NGOD201363 7*African Parks, 20132,363 15.3E 13.4N
+ Lac Fitri AreaNGOD201373African Parks, 201314,167 17.6E 12.9N
NGOD201373African Parks, 20134,167 17.6E 12.9N
+ Zakouma National ParkRSATA2011454Potgieter et al., 201123,326 19.8E 10.9N
RSATA2011454Potgieter et al., 20113,326 19.8E 10.9N

* 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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