kate richardson of london - sanctuaries of new zealand · •“advances in reintroduction biology...
TRANSCRIPT
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.