Considering dispersal in reintroduction and restoration planning. Kate Richardson Massey University/Zoological Society of London

Transcription

1 Considering dispersal in reintroduction and restoration planning Kate Richardson Massey University/Zoological Society of London

2 Based on chapter from upcoming book: Advances in Reintroduction Biology of Australian and NZ Fauna Editors - Doug Armstrong, Matt Hayward, Dorian Moro, Phillip Seddon This talk Out April 2015, CSIRO Press, Melbourne Follow up to 1994 book

3 This talk Considering dispersal in reintroduction and restoration planning Co-authors: Veronica Doerr, Mehregan Ebrahimi, Tim Lovegrove, Kevin Parker

4 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

5 Dispersal and reintroduction Establishment phase: founder group size Alter founder composition Persistence phase: recruitment of juveniles Differential habitat selection e.g. conspecific attraction

6 Reintroductions in New Zealand Shift from pest-free islands To mainland sites with no pests/intensive pest control, and varying connectivity to surrounding landscape

7 Hypothetical example of dispersal from a sanctuary 100m >300m 100m

8 Hypothetical example of dispersal from a sanctuary 100m >300m 100m Sanctuary and release site -predators eradicated/controlled

9 Unmanaged patches linking to Hypothetical larger unmanaged patch example of dispersal from a sanctuary 100m >300m 100m Sanctuary and release site -predators eradicated/controlled

10 Hypothetical translocation of hihi 100m >300m 100m

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

12 First breeding season 100m >300m 100m

13 Typical natal dispersal movements Based on Maungatautari: Male average 1700m (range m) Female average 900m (range m) >300m 100m 100m

14 NI robin at Wenderholm Regional Park 21 robins released in 1999 Wenderholm (60 ha) 4-7 pairs persisted to 2008/ chicks fledged over this period Little recruitment beyond mate replacement of existing pairs Data: Tim Lovegrove, Auckland Council

15 NI robin at Wenderholm Regional Park 60 ha forest Peninsula Trapping/poisoning Moderate connectivity

16 NI robin at Wenderholm Regional Park Dispersal known to at least 2 sites on private land 2-15km away 1-6 pairs at these sites, 2002/ /09 Breeding, but female and chick mortality higher than at Wenderholm

17 NI robin at Wenderholm Regional Park Wenderholm population extinct by 2013/14 Satellite populations 2 individuals remaining by 2014 Dispersal induced translocation failure?

18 Managing dispersal options? 1. Some tools exist to reduce dispersal very context dependent and mixed results

19 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

20 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

21 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

22 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

23 1. Tools to reduce dispersal Supplementary feeding? Anchoring of captive species? Acoustic anchoring? Delayed release?

24 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

25 3. Appropriate site selection Most effective tool in short to medium term Consider: Species-based characteristics Site-based characteristics Interactions

26 Characteristics of species Dispersal propensity Vulnerability of dispersers Distances species can travel? Mortality risk of dispersers in unmanaged areas? Gap-crossing ability? In NZ context predation risk Variation: species, individuals, life stages Variation between species, e.g. tui/bellbird vs saddleback/hihi

27 Characteristics of site Connectivity to surrounding landscape High landscape connectivity a key factor associated with low individual establishment probability (NI robins, Parlato and Armstrong 1 ) Management in surrounding landscape 1 Biological Conservation, 160 (2013)

28 Interactions between species & site Site characteristics Species 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

29 High dispersal propensity + predator-vulnerable High probability of dispersal-related failure Esp. if predator control limited in area and connectivity high E.g. NI kokako, hihi/stitchbird, kaka -> Need large areas subject to ongoing predator control or areas of low connectivity

30 High dispersal propensity + predator-resistant Medium-high probability of dispersalrelated failure E.g. tui, bellbird, tomtit, whitehead Individuals may return to source site, become isolated

31 3. Appropriate site selection: Making decisions Look at connectivity of proposed release site E.g. connectivity index (Parlato and Armstrong 1 ) 1 Biological Conservation, 160 (2013)

32 3. Appropriate site selection: Making decisions Consider dispersal ability of proposed species Use data from other sites where available, e.g. Parlato methods for NI robin No data on dispersal ability? Can infer from similar species? historical range/decline? natural dispersal abilities?

33 3. Appropriate site selection: Making decisions Consider social effects (esp. follow-up releases) Post-release monitoring opportunity to gain valuable information Bellbird carrying tailmounted transmitter

34 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

35 4. Integrated landscape management - what? Long-term goals: Establish self-sustaining populations Provide safe opportunities for dispersal and gene flow to re-establish natural metapopulations

36 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

37 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

38 4. Integrated landscape management - examples Auckland Council, Forest and Bird, Gecko Trust, QEII National Trust Improving migration routes from Hauraki Gulf to Waitakere Ranges Predator control + plantings

39 4. Integrated landscape management - examples Waikato Regional Council, Landcare Research, DoC, Hamilton City Council, Weedbusters, Tui2000 Initial focus on bringing tui into city

40 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

41 Take-home message for sanctuaries Look at potential for expansion of managed areas Move towards longterm integrated approach Collaborations between groups and agencies to work at landscape level

42 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.