fertility control for managing peri-urban kangaroos … · fertility control for managing...
TRANSCRIPT
FERTILITY CONTROL FOR MANAGING PERI-URBAN KANGAROOS IN AUSTRALIA
Claire Wimpenny1, Doug Eckery2
and Lyn A Hinds3
1Conservation Research, Environment and Sustainable Directorate, ACT Government, Canberra, Australia
2USDA, National Wildlife Research Center, Fort Collins, CO, USA3CSIRO Health and Biosecurity, Canberra, Australia
Canberra, Australian Capital Territory – “The Bush Capital”
Eastern Grey Kangaroo (Macropus giganteus)
Eastern Grey Kangaroos in the ACT
• Largest and most abundant native mammal
• High density (up to 7 EGK/ha) and population growth(up to 40% annual growth) in some areas
• Environmental impacts in nature reserves
• Economic impacts on rural lands
• High number of motor vehicle collisions with kangaroos
ACT Kangaroo Management Policy
Goals:
Maintain populations of kangaroos as a significant part of the fauna of the ‘bush capital’ and a component of the grassy ecosystems of the Territory
Manage and minimise the environmental, economic and
social impacts of those kangaroo populations on other
biota, grassy ecosystems and primary production
Native Grassy Ecosystems
Kangaroo grazing is important!!BUTNeed to achieve a grazing regime favourable for the conservation of small animals that depend on the ground-layer vegetation
Residents attitudes to kangaroos and their management 2015
7% against culling under
any circumstances
74% believe it is important to
have kangaroos in reserves
76% support culling in
reserves for conservation
purposes
65% are satisfied with
the management of
kangaroos
76% believe it is important to develop and
apply fertility control
8% hit a kangaroo in the
last 3 years = 14,000
collisions per year Micromex Research
Phone survey of 600 residents
Fertility control for ACT Eastern Grey Kangaroos
• Could provide an additional management tool for EGKs, particularly in discrete populations
• Use to reduce the amount and frequency of culling by limiting population growth rates
• Must be single dose, long-lasting and remotely deliverable
Eastern Grey Kangaroo Reproduction
• Mating is most common in spring and early summer
• Tiny pouch young crawls to pouch and finds teat
• First pouch emergence is at 9.3 months (pouch young)
• Final pouch emergence is at 10.6 months (young at foot)
• Weaned at approx. 18 months
• Embryonic diapause not common in EGKs
GonaCon Immunocontraceptive Vaccine
• Gonadotrophin Releasing Hormone (GnRH) vaccine –antibodies bind to GnRH, stop the production of reproductive hormones
• 2008 sub-adult female EGKs treated with single injection of GonaCon (n=16), 100% infertile for 3 years, >70% still infertile after 10 years
• Capture and injection by hand is very resource intensive
Aims & Methods
Develop a dart
delivery method
Evaluate the effect
on individuals
Evaluate the effect on
populations
Results – Dart selection trials
• Dart selected that successfully expels GonaCon
• Standard injection marker darts too heavy to safely use on EGKs
• Paint selected to temporarily mark treated kangaroos
• Bruising caused by GonaCon dart comparable to darting with anaesthetics
Results – Population level fecundity
Untreated sites
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
FR LR NW UC CB GU MUpro
po
rtio
n o
f ad
ult
fem
ales
wit
h p
ou
ch y
ou
ng
±SE
2015 2016 2017 2018
Results – Population level fecundity
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
ANBG WP TH
pro
po
rtio
n o
f ad
ult
fem
ales
wit
h p
ou
ch
you
ng
±SE
2015 2016 2017 2018
0.00 0.00
Treated sites
Results – Annual population growth
• Annual population growth varies between years and sites (range from -35.3% to +41.5%)
• Treated sites showing negative annual growth, but some untreated sites also had negative growth in some years
Treated site Untreated sites
Is it more efficient and cheaper than other methods?
• At research sites estimate dart delivery 50% more efficient and 75-90% cheaper than capture and treatment
• Preliminary modelling - over 20 years dart delivery would be 30% cheaper than shooting and would involve half as many animals (model by Steve McLeod, NSW DPI)
• Other sites??
What we know so far…..
• GonaCon can be delivered to kangaroos using a dart
• Injection/marker dart works for short distances, but more testing needed for longer distances
• Dart delivered GonaCon causes infertility for at least 3 years
• Has potential to be more efficient and cheaper than capture and treatment and shooting (long-term)
Next steps…
• Continue to monitor treated individuals and populations
• Refine injection/marking system
• Population modelling
• Trial in larger free-ranging populations in more realistic management scenario
Acknowledgements
Thank you to Steve Henry, Richard Barnsley, Melissa Snape, Don Fletcher, Timothy Portas, Renee Brawata, Katherine Jenkins, Sam Reid, Stephanie Pulsford, Jake Gillen, Zohara Lucas, Ryl Parker and Alice Kenney for their contribution to the design, planning and delivery of this
project.
Thank you to the many casual contractors and volunteers who undertook the kangaroo population counts and the research site managers for their support and assistance.
Thank you to Clark Bigger from Pneu-Dart for designing the new injection/marker dart currently being tested.
GonaCon efficacy is being assessed under a Restricted Use Permit from the Australian Pesticides and Veterinary Medicines Authority