Have relocations been a successful management tool for the conservation of oribi antelope in

KwaZulu-Natal?

Tamanna Patel, Dr. Adrian Shrader, Dr. Keenan Stears, Dr. Ian Little

Savanna Science Network Meeting: March 2016

© Keenan Stears

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?

The number of sites that considered each point before any relocation

4

5

6

7

8

9

10

1 2 3 4 5 6 7 8 9 10

No

. of

site

s

Points to consider (Pérez et al. 2012)

The number of sites that considered each point before any relocation

4

5

6

7

8

9

10

1 2 3 4 5 6 7 8 9 10

No

. of

site

s

Points to consider (Pérez et al. 2012)

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?

0

1

2

3

4

5

6

7

8

9

Increasing Decreasing Stable

No

. of

Site

s

Population Trend

Number of criteria initially considered vs. Lambda

Number of criteria considered

5 6 7 8 9 10

Po

pu

lati

on

gro

wth

rat

e (

lam

bd

a)

0.0

0.5

1.0

1.5

2.0

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

Oribi population size

0 10 20 30 40 50Po

pu

lati

on

gro

wth

rat

e (

lam

bd

a)

0.0

0.5

1.0

1.5

2.0

2.5

Suitable habitat (ha)

0 500 1000 1500Po

pu

lati

on

gro

wth

rat

e (

lam

bd

a)

0.0

0.5

1.0

1.5

2.0

2.5

Stocking rate (ha/AU)

0 1 2 3 4 5 6Po

pu

lati

on

gro

wth

rat

e (

lam

bd

a)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Interaction between suitable habitat available & stocking rates vs. Lambda

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

12

34

5

200

400

600

800

1000

1200

1400

1600

Po

pu

lati

on

gro

wth

rat

e (

lam

bd

a)

Stocking rates (ha/AU)

Suitable habitat (ha)

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

Key Lambda (λ)

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