Have relocations been a successful management tool for the conservation of oribi antelope in KwaZulu-Natal? Savanna Science Network Meeting: March 2016 © Keenan Stears Tamanna Patel, Dr. Adrian Shrader, Dr. Keenan Stears, Dr. Ian Little Oribi (Ourebia ourebi) • Highly specialized antelope • Grassland requirements • Numbers are declining in South Africa • Habitat loss & fragmentation • Illegal hunting & poaching • Current status: • Vulnerable Oribi Working Group • Monitor oribi population numbers through annual oribi surveys • Aims to promote the long term survival of oribi in their natural grassland habitats © Ian Little Relocations • What is a relocation? • Movement of an animal or population of animals from an area where they are currently threatened to a more suitable area • Successful relocations • Arabian oryx • White rhinoceros • Springbok Successful Relocation • Results in a self-sustaining population • Births observed every year • Increase in population number • Prior to relocation: • Basic set of criteria should be met: • Aims of the relocation should be defined clearly • Assessment of habitat suitability should be conducted • Post-relocation: • Long-term monitoring over several years Oribi Relocations? Key Questions 1. What is the success rate of previous oribi relocations in KwaZulu-Natal? 2. Have relocations been a successful conservation tool for oribi? 3. What are the factors driving the success/failure of these relocations? 4. How can the success of relocations be improved in future? Data Collection • 10 sites in KwaZulu-Natal with relocated oribi • 10 points to consider before any relocation (Pérez et al. 2012) • Trends at each site → Success/fail • Factors influencing success/failure → Additional questions Pérez et al. 2012 1. Is the population under threat? 2. Have threatening factors been removed/controlled? 3. Are relocations the best tool to use? 4. Are risks for the target species acceptable? 5. Are risks for other species/ecosystem acceptable? 6. Effects of the relocation acceptable to local people? 7. Does the project maximize the likelihood of establishing a viable population? 8. Does the project include clear goals and monitoring? 9. Do enough economic and human resources exist? 10. Do scientific, governmental & stakeholder groups support the relocation? 10 9 8 7 6 No. of sites of No. sites 5 4 1 2 3 4 5 6 7 8 9 10 Points to consider (Pérez et al. 2012) The number of sites that considered each point before any relocation 10 9 8 7 6 No. of sites of No. sites 5 4 1 2 3 4 5 6 7 8 9 10 Points to consider (Pérez et al. 2012) The number of sites that considered each point before any relocation Points that were overlooked at many of the sites: • Have threatening factors been removed or controlled? • Are risks for the target species acceptable? • Does the project maximize the likelihood of establishing a viable population? • Does the project include clear goals and monitoring? • Do enough economic and human resources exist? Success or Fail? 9 8 7 6 5 4 3 No. of No. Sites 2 1 0 Increasing Decreasing Stable Population Trend Number of criteria initially considered vs. Lambda 2.0 1.5 1.0 0.5 Population growth rate (lambda) 0.0 5 6 7 8 9 10 Number of criteria considered Factors driving these trends • A model selection procedure based on small- sample corrected (second order) Akaike’s Information Criterion (AICc) values. • Generalized linear model: • Gamma distribution and a log link function • Best fit model (lowest AICc value): • Oribi population size • Suitable habitat • Stocking rates • Suitable habitat x stocking rates Population size, suitable habitat, stocking rates 2.5 2.5 2.0 2.0 1.5 1.5 1.0 1.0 0.5 0.5 0.0 0.0 Population growth rate (lambda) Population growth rate (lambda) 0 10 20 30 40 50 0 500 1000 1500 Oribi population size Suitable habitat (ha) 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 Population growth rate (lambda) 0 1 2 3 4 5 6 Stocking rate (ha/AU) Interaction between suitable habitat available & stocking rates vs. Lambda 1.0 0.8 Key Lambda (λ) 0.6 -0.2 0.0 0.4 0.2 0.4 0.2 0.6 0.8 0.0 1.0 -0.2 1 2 Population growth rate (lambda) rate growth Population 200 3 400 600 4 Suitable habitat800 (ha) 5 1000 1200 1400 1600 Stocking rates (ha/AU) Conclusion • What is the success rate of previous oribi relocations in KwaZulu-Natal? • Relocation success of 10% • Have relocations been a successful conservation tool for oribi? • No, but they can be successful • Require proper management prior to and post- relocation • Monitoring is very important: • Directly after the relocation • Long-term monitoring plans Conclusion • What are the factors driving the success/failure of these relocations? • Oribi population size • Availability of suitable habitat • Stocking rates of other mammalian herbivores • How can the success of relocations be improved in future? • To use the 10 points as a basic criteria prior to any relocation • To monitor oribi relocations over several years to be able to determine success/fail Management Recommendations • Intermediate sized populations should be relocated (>18 individuals in new area) • High availability of suitable habitat in the new area (>800 ha) • Stocking rates of 3.5 ha/AU • Recommended by the different Bioresource Groups from the Department of Agriculture .