Invasive fauna impact and eradication: an Australian perspective Dr Pip Masters Envisage Environmental Services

Invasive fauna impact and eradication: an Australian perspective Dr Pip Masters Envisage Environmental Services

The Joan Southgate Travelling Scholarship available through AWMS Joan s principal intent for the fund was to assist in reciprocal travel and on-costs between Australasia and Southern Africa for MSc and PhD students studying aspects of wildlife conservation and management

The Australian perspective European settlement 315 endemic land mammals 29 species extinct, 55 species threatened Invasive species the main driver Hard to eradicate on mainland due to size Australia has over 8,300 isiands and 518 with vertebrate invasives Species on islands Once widely distributed on the mainland but now restricted to islands Species only found on islands Refugia for translocated individuals John C. Z. Woinarski, Burbidgec,A.A. and Harrisond P.L. Ongoing unraveling of a continental fauna: Decline and extinction of Australian mammals since European settlement

Predictors of successful eradication Human habitation Topographic complexity Island area Preparedness: planning, strategic approach and adequate funding Gregory, Henderson,Cassey 2014; Pluess et al 2012

Is eradication feasible using a cost effective approach? 1. Does the socio-political environment support eradication? 2. Can you destroy the population faster than replacement? 3. Are all individuals at risk using available techniques? 4. Can the population be monitored at low densities? 5. Can re-infestation be prevented? 6. Does the cost of eradication out weigh the benefits? Bomford and Obrien (1995), Parkes et al (1996)

Implementing effective feral animal control Community support Effective control Effective monitoring and evaluation

Rat eradication on Lord Howe Island Small island (14 km 2 ) 600 km east of mainland, 380 people. Benefits Avoid seven extinctions & save endangered palm-forest ecosystem No more rat baiting, save local palm industry Planning and implementation 2001: feasibility study 2012: $9 m received for rodent eradication using poisonous baits Lack of community trust of government and staff Concerns for livelihoods, health, tourism and environment 2016: resident liaison officer to gain trust and provide facts

Implementing effective feral animal control Community support Effective control Effective monitoring and evaluation

The Kangaroo Island example Third largest island (4,400 km 2 ) Inhabited by around 5,000 people Topographically complex Large areas of thick native vegetation that is difficult to access Invasive species: koalas, goats, deer, pigs, cats, rodents, peacocks

Koalas Iconic arboreal marsupial eats Eucalypt leaves Declining in Queensland and NSW through urbanization and clearing Over abundant in the south (Victoria and SA) Vulnerable to extinction in 2012 Susceptible to dehydration in drought, hence impacted by climate change

Koalas on Kangaroo Island Habitat quality Unsuitable High Quality Medium quality Low quality

Koalas on Kangaroo Island 1994: farmers protecting trees by shooting koalas 1996: population estimate (5,000 koalas) no culling; only sterilization and translocation 2001: more accurate estimate (25,000 koalas) 2016: population size unchanged due to new habitat koalas expand into new forestry plantations >12,700 koalas sterilized, $8.6 m in 21 years 2017: new conflict with future logging of forests Molsher 2017

Implementing effective feral animal control Community support Effective control Effective monitoring and evaluation

Goats Cats

Issue Goats Pigs Deer Cats Stakeholder support Moderate Moderate Moderate High Species recruitment Medium Extremely High Low High Destroy faster than they breed Yes with Judas Difficult Yes Difficult Every individual accessible Yes Possibly Yes No Monitoring at low density Yes, Judas, tracks & scats Tracks, scats & cameras Tracks, scats & cameras Low Reinvasion potential Domestic Low Domestic Pets Non-target issues Shooting : low Poison: high Shooting: low Poison :high

Gaining and maintaining community support, trust and involvement Scoping studies and surveys to determine community support and concerns Employment of trusted locals for control activities Local knowledge and skills, eyes and ears, dob in a deer Local champions Control methods ethical and acceptable

Deer habitat

Management units Goats Identified distribution Seven units: based on natural barriers Trialled eradication in MU1 Worked from south to north to limit reinvasion Parks first to show it could be done Deer One management unit individuals using whole area

Trial effectiveness of Judas goats Number of goats destroyed with and without Judas goats in FCNP (Cape du Couedic to West Bay) Number of destroyed goats 60 50 40 30 20 10 0 J=3 Oct-Dec 06 J=3 Jan-Mar 07 J=2 April- June 07 J=3 J=3 J=1 J=4 July-Sep 07 Oct- Dec07 Jan_Mar 08 April- June 08 J=4 July-Sep 08 Without Judas With Judas J=4 J=4 Oct-Dec 08 Jan-Mar 09

When is goat eradication complete? Monitor using Judas goats for two years Annual searching for sign once Judas goats removed Motion cameras placed in high use areas Community reports

Monitoring to determine decline in distribution and abundance Look for tracks at dams in dry season and estimate probability of occupancy Remote cameras: identifying individuals Changes in age structure based on tooth eruption and wear patterns Time taken to destroy a deer

Decline in probability of occupancy over time Changed data collection method from prints at dams to detection on camera grids in 2014 following trials and comparisons. This allowed for identification of individuals.

Number shot Changes in age structure 45 40 35 30 25 20 15 10 5 0 2006 2006/7 2007/08 2008/09 2009/10 2010/11 2011/12 2012/13 2013/14 14/15 <1 1.1-2 2.1-3 3.1-4 >4

Hours of hunting per deer Time taken to destroy a deer 180 160 140 120 100 80 60 40 20 0 2006/7 2007/8 2008/9 2009/10 2010/11 2011/12 2012/13

Was it worth while? 2005 2008 2008 2017 2017 2017

Biosecurity and preventing reinfestation Risk assessment criteria for domestic goats Risk and detection for escape (vegetation cover, fencing, stock monitoring) Consequence of escape (chance of entering suitable habitat). Deer Domestic deer permitted with conditions (double fencing, tagging, log books)

Implementing effective feral animal control Community support Effective control Effective monitoring and evaluation

Cost of the eradications Costs Aus $1.2M for 10 year project (goats and deer) KI the last 18 goats in FCNP cost approx $235.00 per goat The last three goats in Western River cost around $20,000 each Benefits No on-going control Improved habitat quality and plant diversity No competition with stock, less soil erosion

Unforeseen problems Community State response to volunteer hunting accident Amalgamation of organisations resulting in delays and changes to policies and procedures Accessing forestry and individual landholders Control Recreational hunting accident involving staff member Thick vegetation following fires resulted in difficult access Difficulty to maintain momentum and motivation when densities very low Monitoring Monitoring of goat impacts is seen by upper management as low priority and not maintained

Summary Eradication on inhabited islands is more complex than uninhabited islands Planning and implementation identify feasibility: finances, staff and technologies transparent, consistent and coherent public information control activities carried out by staff trusted by the community science-based monitoring and evaluation of progress and responses Be flexible and adaptable and learn as you go The final stages are the most expensive and difficult to maintain An eradication will be successful when funding, staff & public interest, and control & monitoring options become aligned.

Acknowledgements Nick Markopoulos Brenton Florance KI NRM Board Invasive Animals CRC Caring for our Country Friends of Parks Biosecurity SA Rick Southgate Envisage Env Services Robert Henzell Local volunteers Local Landholders