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Scimitar-horned oryx reintroduction to Chad - Updates from the field

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Presented during the 17h Annual Sahelo-Saharan Interest Group Meeting organized by the NGO Sahara Conservation Fund in Senegal, from 4 to 6 May 2017. The Sahara Conservation Fund (SCF) gathers every year about a hundred people who are interested in the field of Sahelo-Saharan species conservation.

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Scimitar-horned oryx reintroduction to Chad - Updates from the field

  1. 1. 17th Annual Sahelo-Saharan Interest Group Meeting 2 days of talks on biodiversity conservation in the Sahara and in the Sahel Oryx reintroduction to Chad Tim WACHER, Conservation Biologist - Zoological Society of London May 4 – 6, 2017
  2. 2. ORYX – RE-INTRODUCTION TO CHAD Tim Wacher Zoological Society of London
  3. 3. POST-RELEASE MONITORING II • What is post release survivorship? • Habitat use, coping with conditions? • Interactions with other wildlife - livestock • Calf production and survival? • Causes of mortality?
  4. 4. ORGANISATION OF THE OBSERVATIONS • Group 1 – 21 Oryx 8 Males 13 Females Released 14 Aug. 2016 • Group 2 – 14 Oryx 6 Males : 8 Females Released 21 Jan. 2017 • Group 3 – 37 Oryx 14 Males : 23 Females Not released: + 7 CALVES TO DATE 81 oryx in Chad April 2017 (including calves)
  5. 5. THE MONITORING TEAM Abe (Bobby) Zaid Habib Ali Krazidi Abeye © Tim Wacher © Tim Wacher © Tim Wacher
  6. 6. POST-RELEASE SURVIVAL • Group 1 – 262 days….. 100% • Group 2 – 102 days…..100% [Group 3 – all 37 alive in prelease 03/05/2017]
  7. 7. HABITAT CONDITIONS Group 1 - August 2016 21 Aug. 2017 © Tim Wacher
  8. 8. HABITAT CONDITIONS September 2016 07 Sep. 2016© Tim Wacher
  9. 9. 25 Feb. 2017 GROUP 1 – END OF FEBRUARY (No rain or free water since September – Excellent body condition) HABITAT CONDITIONS February 2017 © Tim Wacher
  10. 10. END OF MARCH 2017 Some oryx losing body condition Adult male B34M : On the day he returned spontaneously to the feeding station – (compare to next slide) B34M walked directly to the release site after 7 months living independently in the Group 1 herd >30 km away 30 Mar. 2017© Tim Wacher
  11. 11. 03 Apr. 2017 ADULT MALE B34M 4 DAYS AFTER RETURN TO FEEDING STATION Compare body condition to previous slide… © Tim Wacher
  12. 12. GROUP 1 – ORYX NOT USING FEED STATION AT ALL 12 Apr. 2017 © Tim Wacher
  13. 13. DRY SEASON IMMOBILITY ALERTS 3 ORYX IN THIS GROUP TRIGGERED IMMOBILITY ALERTS AROUND THE TIME THIS LATE AFTERNOON PICTURE WAS TAKEN – ALMOST ALL MOVEMENT NOCTURNAL AT THIS SEASON © Tim Wacher
  14. 14. 6mm Rain – 15-16 April 2017 Rainfall and cloud cover brought temporary relief from high temperatures and aridity and created water pools for a few days over a wide area in mid-April (Meteorological data from oryx camp automatic weather station) © Tim Wacher © Tim Wacher
  15. 15. AFTER RAIN – ACTIVE MIDDAY 19 Apr. 2017 © Tim Wacher
  16. 16. AFTER RAIN – ACTIVE MIDDAY 22 Apr. 2017 © Tim Wacher
  17. 17. OTHER WILDLIFE AND LIVESTOCK APRIL 2017 TRANSECT SURVEY Mahamat Hatcha Coordinateur du Reserve et l’Equipe DCFAP © Tim Wacher
  18. 18. HABITAT USE LINE TRANSECT SURVEY Feb. 2017 February Group 1 oryx (red points) – burnt areas (grey) and livestock relative density contours 15,865 dorcas (cv 14.35%) 52,550 Tropical Livestock Units (cv 29%)
  19. 19. B36F – CALVING BEHAVIOUR 27 Jan. 2017 The first female to give birth on the project, was B36F on 21 September 2016 She isolated from Group 1 on the day she gave birth: considered typical oryx behaviour. She has not re-joined a herd since, becoming widely separated from the only herd available © Tim Wacher
  20. 20. GROUP 1 B36-01 Born 23/Sep/2016 16 Apr. 2017© Tim Wacher
  21. 21. B23F – CALVING BEHAVIOUR B23F also separated from Group 1 to give birth : the male who joined her from group 1 in a consort pair shortly afterwards was B38M, not the socially dominant male of Group 1, B40M.
  22. 22. B23F – CALVING DETAILS 0 5 10 15 20 25 Group size Female Group 1 Male Calf B23F’s calf was reported to be very small and was no longer seen after 10 days. The dam moved widely with group size and composition more variable A sign of emerging more flexible social structures
  23. 23. B31F – CALVING BEHAVIOUR B31F also separated to give birth and consorted with 2 different males post-partum; Neither was the dominant male of Group 1 with whom she had associated since arrival in Chad. Detecting this distinctive spatial and social indicator of calving from satellite location data is proving difficult and planned automatic alerts based on it have not yet been developed. © Tim Wacher
  24. 24. GROUP 2 – 2 CALVES B02F gave birth at the feeding station, at very high risk from jackals attracted there: © Tim Wacher
  25. 25. GROUP 2 – 2 CALVES Jackals are present in numbers all night long every night at the feeding station water trough
  26. 26. GROUP 2 – FIRST CALF B02-01 was killed by jackals 250m from the feeding station within 24 hours : © Tim Wacher
  27. 27. GROUP 2 – SECOND CALF R30-01 and all calves born at the feeding station subsequently have been herded back to the pre-release pens successfully © Tim Wacher
  28. 28. 12 calves born (to 27.04.2017) • Wild born wet season release Survival 3 calves – 1 mortality (lost calf small, born mid dry season, abandoned?) 60% • Wild born – dry season release 2 calves – 2 mortalities (1 killed by jackal / 0% 1 abandoned after moving back into pen system) • Pre-release pen birth 7 calves 100%
  29. 29. NEXT RELEASE – AUG 2017 Manage calving in relation to dry season post-release behaviour © Tim Wacher
  30. 30. MALE CONFLICT IN PRE-RELEASE PENS STRONGLY ESCALATED WITH ONSET OF CALFING © Tim Wacher
  31. 31. SUMMARY • RELEASE ORYX SURVIVAL OVER FIRST 8 MONTHS – 100% • DISPERSAL MODERATE AND GROUP 1 HERD COHERENT • FIDELITY TO / AWARENESS OF RELEASE SITE PROVEN AFTER 7 MONTHS • CALVING IN THE WILD SUCCESSFUL ALTHOUGH LOW POPULATION SIZE HAS CONTRIBUTED TO 2 of 3 BREEDING FEMALES LOSING CONTACT WITH HERDS FOLLOWING TYPICAL ISOLATION BEHAVIOR AT BIRTH • MAINTENANCE OF THE FEEDING STATION AT THE RELEASE SITE HAS CREATED A CONCENTRATION OF JACKALS REQUIRING LOCAL MANAGEMENT OF BREEDING FEMALE ORYX • MID-DRY SEASON SOME ORYX ARE HOLDING BODY CONDITION BETTER THAN OTHERS - A SHORT RAIN STORM IN EARLY APRIL STIMULATED AN IMMEDIATE CHANGE IN BEHAVIOR AND RAPID RESPONSE IN BODY CONDITION FOR MANY • CONCLUSIONS PREMATURE UNTIL FIRST FULL CALENDAR YEAR COMPLETED

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