Seabird Group Conference, 2018

Presentation on work from my PhD about the effect of environmental heterogeneity on seabird behaviour and fitness. Thank you to the scientific committe for awarding me with joint first student presentation for this talk.

Transcript

1. The Consequences of Environmental Heterogeneity Alice Trevail, J Green, J Sharples, J Polton, P Miller & S Patrick FAME data from Ellie Owen, Mark Bolton et al. @AliceTrevail alice.trevail@Liverpool.ac.uk
2. Optimal foraging theory
3. Optimal foraging theory
4. Resource heterogeneity
5. Resource heterogeneity
6. Resource heterogeneity Richard Shucksmith
7. • Not all heterogeneous resource distributions are equal Resource heterogeneity
8. • Not all heterogeneous resource distributions are equal • Distribution of patches travel distance Resource heterogeneity
9. • Not all heterogeneous resource distributions are equal • Distribution of patches travel distance • Heterogeneity Number of foragers at each patch Resource heterogeneity Matt Doggett
10. Q: How does resource heterogeneity influence Foraging behaviour ? & Fitness ? Resource heterogeneity
11. • The environment can define resource distributions Environmental heterogeneity = proxy for resource heterogeneity Environmental heterogeneity
12. Data from 15 colonies around UK range • Foraging behaviour: GPS data 415 birds 1567 trips • Reproductive success Muckle Skerry Copinsay Winnyfold Fowlsheugh Isle of May Coquet Filey Bempton Cliffs Puffin Bardsey Skomer St Martins Rathlin Colonsay Lambay Black-legged kittiwakes
13. Data from 15 colonies around UK range • Foraging behaviour: GPS data • Reproductive success Muckle Skerry Copinsay Winnyfold Fowlsheugh Isle of May Coquet Filey Bempton Cliffs Puffin Bardsey Skomer St Martins Rathlin Colonsay Lambay Does environmental heterogeneity influence 1. Kittiwake foraging behaviour ? 2. Kittiwake reproductive success ? Black-legged kittiwakes
14. Quantifying environmental heterogeneity 1. Environmental variables for spatial points • Bathymetry • Stratification • Front density, persistence & distance
15. Quantifying environmental heterogeneity 1. Environmental variables for spatial points 2. Principal coordinate analysis • Account for variation in all environmental variables Axis 1 Axis 2 Colony A Colony B
16. Quantifying environmental heterogeneity 1. Environmental variables for spatial points 2. Principal coordinate analysis • Account for variation in all environmental variables Axis 1 Axis 2 Colony A Colony B Heterogeneous Homogeneous
17. Quantifying environmental heterogeneity 1. Environmental variables for spatial points 2. Principal coordinate analysis 3. Heterogeneity = dispersion of points along principal coordinate axes • Continuous variable - average distance from colony mean Axis 1 Axis 2 Colony A Colony B Heterogeneous Homogeneous
18. Quantifying environmental heterogeneity • Can identify gradient between colonies (p < 0.01) 0.8 1.2 1.6 2.0 Coquet Winnyfold Isle of May Muckle Skerry Fowlsheugh St Martins Lambay Filey Bempton Skomer Puffin Island Bardsey Colonsay Rathlin Colony Average distance from colony mean Heterogeneous Homogeneous
19. Quantifying environmental heterogeneity • Can identify gradient between colonies (p < 0.01) 0.8 1.2 1.6 2.0 Coquet Winnyfold Isle of May Muckle Skerry Fowlsheugh St Martins Lambay Filey Bempton Skomer Puffin Island Bardsey Colonsay Rathlin Copinsay Colony Average distance from colony mean Heterogeneous Homogeneous Increasing heterogeneity Muckle Skerry Copinsay Winnyfold Fowlsheugh Isle of May Coquet Filey Bempton Cliffs Puffin Bardsey Skomer St Martins Rathlin Colonsay Lambay
20. Quantifying foraging behaviour 1. Trip characteristics • Duration • Max distance • Total distance
21. Quantifying foraging behaviour 2. At-sea area use • Size of 50% core area 1. Trip characteristics • Duration • Max distance • Total distance
22. Quantifying foraging behaviour 2. At-sea area use • Size of 50% core area • Overlap between individuals 1. Trip characteristics • Duration • Max distance • Total distance
23. Quantifying foraging behaviour 3. Behavioural state • HMM model 2. At-sea area use • Size of 50% core area • Overlap between individuals 1. Trip characteristics • Duration • Max distance • Total distance transit forage rest transit
24. Quantifying foraging behaviour 3. Behavioural state • HMM model • Proportion of time in different states 2. At-sea area use • Size of 50% core area • Overlap between individuals 1. Trip characteristics • Duration • Max distance • Total distance transit forage rest transit
25. Results: foraging behaviour 1. Trip characteristics 1 2 3 -1 0 1 2 Environmental heterogeneity
26. Results: foraging behaviour 1. Trip characteristics 1 2 3 -1 0 1 2 Environmental heterogeneity Trip Duration ( log (h) )
27. Results: foraging behaviour 1. Trip characteristics 1 2 3 -1 0 1 2 Environmental heterogeneity Trip Duration ( log (h) ) • Significantly longer trips • No effect on max or total distance
28. Results: foraging behaviour 2. At-sea area use 1. Trip characteristics 1 2 3 -1 0 1 2 0.05 0.10 0.15 0.20 -1 0 1 2 Environmental heterogeneity Trip Duration ( log (h) ) Foraging Overlap (BA index) • Significantly longer trips • No effect on max or total distance
29. Results: foraging behaviour 2. At-sea area use 1. Trip characteristics 1 2 3 -1 0 1 2 0.05 0.10 0.15 0.20 -1 0 1 2 Environmental heterogeneity Trip Duration ( log (h) ) Foraging Overlap (BA index) • Significantly longer trips • No effect on max or total distance • Significantly more overlap • No effect on foraging area
30. Results: foraging behaviour 3. Behavioural state 2. At-sea area use 1. Trip characteristics 1 2 3 -1 0 1 2 0.05 0.10 0.15 0.20 -1 0 1 2 Environmental heterogeneity Trip Duration ( log (h) ) Foraging Overlap (BA index) Proportion of time • Significantly longer trips • No effect on max or total distance • Significantly more overlap • No effect on foraging area 0.2 0.4 0.6 -1 0 1 2 behaviour Forage Transit Rest
31. Results: foraging behaviour 3. Behavioural state 2. At-sea area use 1. Trip characteristics 1 2 3 -1 0 1 2 0.05 0.10 0.15 0.20 -1 0 1 2 Environmental heterogeneity Trip Duration ( log (h) ) Foraging Overlap (BA index) Proportion of time behaviour Forage Transit Rest • Significantly longer trips • No effect on max or total distance • Significantly more overlap • No effect on foraging area • Significantly more foraging • Significantly less transiting 0.2 0.4 0.6 -1 0 1 2
32. Results: reproductive success 0.5 1.0 -1 0 1 2 Environmental heterogeneity Mean fledglings per nest
33. • Environmental heterogeneity = lower reproductive success (p < 0.001) Results: reproductive success 0.5 1.0 -1 0 1 2 p < 0.001, R2=0.27 Environmental heterogeneity Mean fledglings per nest
34. • Environmental heterogeneity = lower reproductive success (p < 0.001) Results: reproductive success 0.5 1.0 -1 0 1 2 p < 0.001, R2=0.27 63% decrease in success across range of environmental heterogeneity Environmental heterogeneity Mean fledglings per nest
35. Why does fitness decline with heterogeneity? 1. Are homogeneous sites higher quality? Heterogeneity Environment metric
36. Why does fitness decline with heterogeneity? 1. Are homogeneous sites higher quality? Homogeneous Heterogeneous Increase in foraging range Heterogeneity Environment metric
37. Why does fitness decline with heterogeneity? 1. Are homogeneous sites higher quality? Homogeneous Heterogeneous Increase in foraging range Heterogeneity Environment metric No links No change in max foraging distance
38. Why does fitness decline with heterogeneity? 2. Does heterogeneity make it harder to find food?
39. Why does fitness decline with heterogeneity? 2. Does heterogeneity make it harder to find food? No change in total distance travelled
40. Why does fitness decline with heterogeneity? 2. Does heterogeneity make it harder to find food? No change in total distance travelled No change in size of core foraging area
41. Why does fitness decline with heterogeneity? 3. Does heterogeneity increase competition at resource patches? Homogeneous Heterogeneous Increase in overlap
42. Why does fitness decline with heterogeneity? 3. Does heterogeneity increase competition at resource patches? Trip duration increased Homogeneous Heterogeneous Increase in overlap
43. Why does fitness decline with heterogeneity? 3. Does heterogeneity increase competition at resource patches? Trip duration increased Time spent foraging increased Homogeneous Heterogeneous Increase in overlap
44. Why does fitness decline with heterogeneity? 3. Does heterogeneity increase competition at resource patches? Trip duration increased Overlap between individuals increased Time spent foraging increased Homogeneous Heterogeneous Increase in overlap
45. Summary Heterogeneity may cluster resources into patches This increases competition at patches Foraging takes longer Poorer chick provisioning Reduced breeding success
46. Summary • Heterogeneity could effect species distributions • Important consideration in studies of population resilience to environmental stressors?
47. Thanks to… FAME project Many others for their help in the field Steve Dodd Matt Wood Ed Stubbings Birgitta Buche Kendrew Colhoun Liam McFaul SEGUL Lots more… Ellie Owen Mark Bolton Ewan Wakefield Kendrew Colhoun Louise Soanes Julia Baer Matthew Carroll Francis Daunt Tim Guilford Roddy Mavor Mark Newall Stephen Newton Gail Robertson Akiko Shoji Steve Votier Sarah Wanless
48. In brief: Environmental heterogeneity increases foraging competition & reduces breeding success @AliceTrevail alice.trevail@Liverpool.ac.uk