ASAB easter conference, 2017

Talk at the Easter conference of the Association for the Study of Animal Behaviour, Liverpool, April 2017. Here we show that plasticity in behaviour varies with environmental heterogeneity.

Transcript

1. Extrinsic drivers of foraging behaviour in a central-place predator Alice M Trevail, Jonathan A Green, Jonathan Sharples, Jeffrey Polton, John Arnould & Samantha C Patrick @AliceTrevail alice.trevail@Liverpool.ac.uk
2. What shapes behavioural plasticity? • Widespread variability in foraging behaviours Individual / Population Ed Schneider Liam Quinn Antarctica.gov.au
3. What shapes behavioural plasticity? • Widespread variability in foraging behaviours • Environment can influence foraging habitat choice Environment can shape resource availability E.g. hotspots Ed Schneider Liam Quinn Antarctica.gov.au
4. What shapes behavioural plasticity? • Widespread variability in foraging behaviours • Environment can influence foraging habitat choice • Q: How plastic are foraging behaviours over time? Respond to resource availability at different time scales? Adapt to predictability? Ed Schneider Liam Quinn Antarctica.gov.au
5. What shapes behavioural plasticity? • Widespread variability in foraging behaviours • Environment can influence foraging habitat choice • Q: How plastic are foraging behaviours over time? • Q: Does environment influence plasticity? Heterogeneity predictability May shape variation between populations Ed Schneider Liam Quinn Antarctica.gov.au
6. Extrinsic drivers of foraging behaviour
7. Extrinsic drivers of foraging behaviour Spatial variation: Depth Direction of currents Water column structure Resource availability
8. Extrinsic drivers of foraging behaviour Spatial variation: Depth Direction of currents Water column structure Resource availability Q1 How does space influence foraging behaviour?
9. Extrinsic drivers of foraging behaviour Temporal variation: Tide = predictable 12 hr cycle Speed & direction of currents Prey availability accessibility
10. Extrinsic drivers of foraging behaviour Temporal variation: Tide = predictable 12 hr cycle Speed & direction of currents Prey availability accessibility Q2 Does foraging behaviour change with tide?
11. Extrinsic drivers of foraging behaviour Depth Tide
12. Extrinsic drivers of foraging behaviour Depth Tide Tidal coupling hypothesis (Zamon 2003; MEPS)
13. Tidal coupling hypothesis
14. Tidal coupling hypothesis
15. Tidal coupling hypothesis
16. Tidal coupling hypothesis
17. Tidal coupling hypothesis
18. However Geographic variation in behavioural response to tidal cycle (Cox et al 2003; MEPS)
19. Hypothesis: Environmental heterogeneity important at this stage Predictable cues Behaviour
20. Study question: Does tidal influence on behaviour vary with spatial heterogeneity? Q3
21. Skomer Puffin Is. Skomer Puffin Island Spatially heterogeneous Hypothesis: More behavioural plasticity Spatially homogeneous Hypothesis: Less behavioural plasticity Bathymetry Longitude Latitude 51.4 N 51.6 N 51.8 N 52 N 52.2 N 52.4 N 6 W 5.5 W 5 W 4.5 W 0 20 40 60 80 100 120 140 Water depth (m) 140 0 10 km Study sites of contrasting heterogeneity
22. Methods: seabird tracking • Study species = Black legged kittiwake • Indicator species in marine policy • GPS loggers (iGotU 120) • Multiple trips per individual • Puffin Island: 505 trips, 59 individuals, 6 years • Skomer Island: 22 trips, 10 individuals, 1 year Latitude (°) 4.4 4.2 4 53.3 53.4 53.5 53.6 4.3 4.1 Puffin Island 52 51.9 51.8 51.7 Skomer Island 5.5 5.4 5.3 5.2 Longitude (°) @AliceTrevail
23. 5.6 5.8 5.2 51.6 52 51.8 5.4 Latitude (°N) Depth Longitude (°W) 4.5 W 0 20 40 60 80 100 120 140 Water depth (m) 140 0 Methods: quantifying habitat selection
24. 5.6 5.8 5.2 51.6 52 51.8 5.4 Latitude (°N) Depth Longitude (°W) 4.5 W 0 20 40 60 80 100 120 140 Water depth (m) 140 0 5.6 5.8 5.2 5.4 Depth for GPS points = Used (1) Methods: quantifying habitat selection
25. 5.6 5.8 5.2 51.6 52 51.8 5.4 Latitude (°N) Depth Longitude (°W) 4.5 W 0 20 40 60 80 100 120 140 Water depth (m) 140 0 5.6 5.8 5.2 5.4 Depth for GPS points = Used (1) 5.6 5.8 5.2 5.4 Depth for random points x10 = Available (0) Methods: quantifying habitat selection
26. 5.6 5.8 5.2 51.6 52 51.8 5.4 Latitude (°N) Depth Longitude (°W) 4.5 W 0 20 40 60 80 100 120 140 Water depth (m) 140 0 5.6 5.8 5.2 5.4 Depth for GPS points = Used (1) 5.6 5.8 5.2 5.4 Depth for random points x10 = Available (0) Binomial GLMM Response = Used/Available (1/0) Methods: quantifying habitat selection
27. Can split tidal cycle by: flow rate and tidal height Methods: quantifying tidal variation Tidal height (m) Time Low Water High Water Low Water High Water Prey behaviour Prey accessibility
28. Methods: quantifying tidal variation Tidal height (m) Time Low Water High Water Slack Low Slack Low: • Flow rate = Low • Water height = Low Low Water High Water
29. Flood: • Flow rate = High • Water height = Increasing Methods: quantifying tidal variation Tidal height (m) Time Low Water High Water Low Water High Water Slack Low Flood
30. Slack High: • Flow rate = Low • Water height = High Methods: quantifying tidal variation Tidal height (m) Time Low Water High Water Low Water High Water Slack Low Flood Slack High
31. Ebb: • Flow rate = High • Water height = Decreasing Methods: quantifying tidal variation Tidal height (m) Time Low Water High Water Low Water High Water Slack Low Flood Slack High Ebb
32. Results: Habitat selection Depth (m) Probability of habitat use 0.00 0.25 0.50 0.75 1.00 0 50 100
33. Habitat influences foraging behaviour Depth (m) Probability of habitat use 0.00 0.25 0.50 0.75 1.00 0 50 100 At species level: kittiwakes select for shallower water Kittiwake habitat selection
34. Habitat selection varies with tide Depth (m) Probability of habitat use 0.00 0.25 0.50 0.75 1.00 0 50 100 Tide = a predictable 12hr cycle = influences habitat selection Habitat selection by tide state Slack Low Flood Slack High Ebb
35. Habitat selection varies with tide Depth (m) Probability of habitat use Tide = a predictable 12hr cycle = influences habitat selection Selection strongest during flood slack high High flow rate / high water May alter prey fish distribution (Zamon 2003; MEPS) Habitat selection by tide state Slack Low Flood Slack High Ebb 0.00 0.25 0.50 0.75 1.00 0 50 100
36. 0 50 100 0 50 100 Tidal variability varies with colony Depth (m) Probability of habitat use Tide = more influence at Skomer 0.00 0.25 0.50 0.75 1.00 Habitat selection by tide state Slack Low Flood Slack High Ebb Puffin Island; 2016 Skomer Island; 2016
37. 0 50 100 0 50 100 Tidal variability varies with colony Depth (m) Probability of habitat use Tide = more influence at Skomer Strongest selection at different tidal states 0.00 0.25 0.50 0.75 1.00 Habitat selection by tide state Slack Low Flood Slack High Ebb Puffin Island; 2016 Skomer Island; 2016
38. 0 50 100 0 50 100 Tidal variability varies with colony Depth (m) Probability of habitat use Tide = more influence at Skomer Strongest selection at different tidal states Environmental heterogeneity influences tidal coupling 0.00 0.25 0.50 0.75 1.00 Habitat selection by tide state Slack Low Flood Slack High Ebb Puffin Island; 2016 Skomer Island; 2016
39. • Foraging behaviour flexible over 12 hour cycle Short term plasticity in foraging behaviour
40. • Foraging behaviour flexible over 12 hour cycle • Plasticity varies between populations Short term plasticity in foraging behaviour Environmental heterogeneity Predictable cues Behaviour
41. Long term plasticity in foraging behaviour 0.00 0.25 0.50 0.75 1.00 0 50 100 Habitat selection by year 2010 2011 2013 2015 2016 Probability of habitat use Foraging behaviour differs between years Can’t explain this by 12hr tidal cycle Inter-annual differences in environment, e.g. ocean fronts Depth (m) Puffin Island
42. Next steps: Skomer Puffin Is. Rathlin 2017 tracking: Rathlin, Skomer & Puffin To explore a gradient in tidal variability coastal morphology Individual level Inter-annual variability in habitat selection
43. Thanks to Puffin Island field teams, including: Federico de Pascalis, Harriet Clarke, Ruth Dunn, Phil Collins, Louise Soanes & Steve Dodd As well as Skomer wardens, B and Ed, & Ros Green
44. In brief: Plasticity in foraging behaviour varies with environmental heterogeneity Thank you for listening! Any Questions? @AliceTrevail alice.trevail@Liverpool.ac.uk