Considering dispersal in reintroduction and restoration

planning

Kate Richardson

Massey University/Zoological Society of London

This talk • Based on chapter from

upcoming book:

• “Advances in Reintroduction Biology of Australian and NZ Fauna”

• Editors - Doug Armstrong, Matt Hayward, Dorian Moro, Phillip Seddon

• Out April 2015, CSIRO Press, Melbourne Follow up to 1994 book

This talk

• “Considering dispersal in reintroduction and restoration planning”

• Co-authors:

• Veronica Doerr, Mehregan Ebrahimi, Tim Lovegrove, Kevin Parker

Dispersal and reintroduction • Can influence success in

multitude of ways

• Short term: immediate post-release dispersal out of unmanaged areas

• Long term: natal dispersal (juveniles) or ongoing dispersal of adults

• Or conversely – may fail to lack of dispersal -> ↓ genetic

or demographic exchange with other populations

Dispersal and reintroduction

• Establishment phase:

• ↓ founder group size

• Alter founder composition

• Persistence phase:

• ↓ recruitment of juveniles

• Differential habitat selection – e.g. conspecific attraction

Reintroductions in New Zealand

• Shift from pest-free islands

• To mainland sites with no pests/intensive pest control, and varying connectivity to surrounding landscape

>300m

100m

100m

Hypothetical example of dispersal from a sanctuary

>300m

100m

100m

Hypothetical example of dispersal from a sanctuary

Sanctuary and release site -predators eradicated/controlled

>300m

Sanctuary and release site -predators eradicated/controlled

100m

100m

Unmanaged patches linking to larger unmanaged patch Hypothetical

example of dispersal from a sanctuary

>300m

100m

100m

Hypothetical translocation of hihi

>300m

100m

100m

Typical post-release movements in first week Based on Ark, Maungatautari + Bushy Park monitoring: distances >6 km gaps 100m (++ ?), <300m

>300m

100m

100m

First breeding season

>300m

100m

100m

Typical natal dispersal movements Based on Maungatautari: Male average 1700m (range 0-5170m) Female average 900m (range 0-3425m)

• 21 robins released in 1999

• Wenderholm (60 ha)

• 4-7 pairs persisted to 2008/09

• 241 chicks fledged over this period

• Little recruitment beyond mate replacement of existing pairs

NI robin at Wenderholm Regional Park

Data: Tim Lovegrove, Auckland Council

NI robin at Wenderholm Regional Park

60 ha forest Peninsula Trapping/poisoning Moderate connectivity

• Dispersal known to at least 2 sites on private land 2-15km away

• 1-6 pairs at these sites, 2002/03-2008/09

• Breeding, but female and chick mortality higher than at Wenderholm

NI robin at Wenderholm Regional Park

• Wenderholm population extinct by 2013/14

• Satellite populations – 2 individuals remaining by 2014

• Dispersal induced translocation failure?

NI robin at Wenderholm Regional Park

Managing dispersal – options?

• 1. Some tools exist to reduce dispersal – very context dependent and mixed results

Managing dispersal – options?

• 1. Some tools exist to reduce dispersal – very context dependent and mixed results

• 2. Can translocate more individuals to mitigate for losses to dispersal

Managing dispersal – options?

• 1. Some tools exist to reduce dispersal – very context dependent and mixed results

• 2. Can translocate more individuals to mitigate for losses to dispersal

• Short term fixes • Assume dispersal is maladaptive

• Fail to fully take into account why individuals disperse and why this can be a problem

Managing dispersal – options?

• 1. Some tools exist to reduce dispersal – very context dependent and mixed results

• 2. Can translocate more individuals to mitigate for losses to dispersal

• 3. Appropriate site selection

Managing dispersal – options?

• 1. Some tools exist to reduce dispersal – very context dependent and mixed results

• 2. Can translocate more individuals to mitigate for losses to dispersal

• 3. Appropriate site selection

• 4. Integrated landscape management approach

1. Tools to reduce dispersal

• Supplementary feeding?

• Anchoring of captive species?

• Acoustic anchoring?

• Delayed release?

2. Translocating more individuals

• Can be successful if dispersal only post-release

• Multiple releases over multiple years –effective where dispersers have ↑ survival probabilities but geographically isolated?

• If ongoing translocations needed – query sustainability of reintroduction attempt

3. Appropriate site selection

• Most effective tool in short to medium term

• Consider:

• Species-based characteristics

• Site-based characteristics

• Interactions

Characteristics of species

Dispersal propensity

• Distances species can travel?

• Gap-crossing ability?

• Variation: species, individuals, life stages

Vulnerability of dispersers

• Mortality risk of dispersers in unmanaged areas?

• In NZ context – predation risk

• Variation between species, e.g. tui/bellbird vs saddleback/hihi

Characteristics of site

• Connectivity to surrounding landscape

• High landscape connectivity a key factor associated with low individual establishment probability (NI robins, Parlato and Armstrong1)

• Management in surrounding landscape

1 Biological Conservation, 160 (2013) 97-104

Interactions between species & site

Species characteristics

Site characteristics

Low connectivity

High connectivity

Low dispersal propensity Predator-resistant

?

Low dispersal propensity Predator-vulnerable

?

High dispersal propensity Predator-resistant

? ?

High dispersal propensity Predator-vulnerable

? X

High dispersal propensity + predator-vulnerable

• High probability of dispersal-related failure

• Esp. if predator control limited in area and connectivity high

• -> Need large areas subject to ongoing predator control or areas of low connectivity

• E.g. NI kokako, hihi/stitchbird, kaka

High dispersal propensity + predator-resistant

• Medium-high probability of dispersal-related failure

• Individuals may return to source site, become isolated

• E.g. tui, bellbird, tomtit, whitehead

3. Appropriate site selection: Making decisions

• Look at connectivity of proposed release site

• E.g. connectivity index (Parlato and Armstrong1)

1 Biological Conservation, 160 (2013) 97-104

3. Appropriate site selection: Making decisions

• No data on dispersal ability? Can infer from…

• similar species?

• historical range/decline?

• natural dispersal abilities?

• Consider dispersal ability of proposed species

• Use data from other sites where available, e.g. Parlato methods for NI robin

3. Appropriate site selection: Making decisions

• Consider social effects (esp. follow-up releases)

• Post-release monitoring – opportunity to gain valuable information

Bellbird carrying tail-mounted transmitter

4. Integrated landscape management - what?

• Wider landscape managed beyond reintroduction sites/sanctuaries

• Predict how/where reintroduction sites functionally connected to other sites

• Allow targeting of management to most relevant connections/protected areas

• Dispersal viewed as natural component of life history

4. Integrated landscape management - what?

• Long-term goals:

• Establish self-sustaining populations

• Provide safe opportunities for dispersal and gene flow to re-establish natural meta-populations

4. Integrated landscape management - how?

• Uptake of new methods/modelling approaches to assess site suitability and landscape connectivity

• Improved technologies for predator control

• Increased collaboration between agencies and communities

• Incorporation into restoration planning from outset – consider priorities where conflicts btwn species

4. Integrated landscape approach - examples

• NZ Landcare Trust and WWF-NZ

• Pilot project: Kiwi Coast Project

• Multiple aims, including facilitating safe movement of dispersing juvenile kiwi

• Auckland Council, Forest and Bird, Gecko Trust, QEII National Trust

• Improving migration routes from Hauraki Gulf to Waitakere Ranges

• Predator control + plantings

4. Integrated landscape management - examples

4. Integrated landscape management - examples

• Waikato Regional Council, Landcare Research, DoC, Hamilton City Council, Weedbusters, Tui2000

• Initial focus on bringing tui into city

Take-home message for sanctuaries

• Consider adverse effects of dispersal in proposed translocations

• Many NZ species subject to translocation will disperse

• Degree to which this an issue dependent on

connectivity of site and vulnerability of species to predation

Take-home message for sanctuaries

• Look at potential for expansion of managed areas

• Move towards long-term integrated approach

• Collaborations between groups and agencies to work at landscape level

Acknowledgments

• Co-authors: Veronica Doerr, Mehregan Ebrahimi, Tim Lovegrove, Kevin Parker

• Thanks to Doug Armstrong, John Innes, Phil Seddon for providing feedback

• Hihi Recovery Group, MEIT, Ark in the Park, Bushy Park for hihi radio tracking projects

• Photo credits: Bill Beale, Laurence Bechet, Phil Brown, Isabel Castro, Neil Fitzgerald, Ken Jacobsen, Rainer Kant, David Mudge, Angela Wickham, Eric Wilson.