British Ornithological Union, 2018

Presentation on the role of environmental heterogeneity in shaping foraging behaviour and driving reproductive success at the British Ornithological Union, March 2017. Here we show that environmental heterogeneity increases trip duration, and decreases breeding success, using data from 15 colonies around the UK. This talk was awarded 2nd prize.

Transcript

1. Population & Individual responses to environmental variability Alice Trevail, J Green, J Sharples, J Polton, P Miller & S Patrick @AliceTrevail alice.trevail@Liverpool.ac.uk
2. Environmental variability @AliceTrevail • Birds experience a wide range of environmental conditions e.g. Migration
3. • Birds experience a wide range of environmental conditions e.g. Migration Breeding range > 60 % species = wide-spread (BirdLife 2008) Environmental variability @AliceTrevail
4. • Birds experience a wide range of environmental conditions Over time Breeding range > 60 % species = wide-spread (BirdLife 2008) Environmental variability @AliceTrevail Global temperature anomaly (°C)
5. • The environment plays a key role in shaping resource availability Environmental variability @AliceTrevail
6. • The environment plays a key role in shaping resource availability • Across environments, how do animals locate essential resources? Environmental variability @AliceTrevail
7. • The environment plays a key role in shaping resource availability • Across environments, how do animals locate essential resources? Environmental variability @AliceTrevail Q: Adapt different foraging strategies across distribution? OR Q: Are species suited to an optimal environment?
8. Adaptations to the environment @AliceTrevail ? ? Environment Influences resource availability Foraging behaviour Allows animals to access resources Reproductive success Measure of fitness
9. Adaptations to the environment @AliceTrevail Environment Influences resource availability Foraging behaviour Allows animals to access resources Reproductive success Measure of fitness If foraging strategies as adaptations… Maintained
10. Adaptations to the environment @AliceTrevail Environment Influences resource availability Foraging behaviour Allows animals to access resources Reproductive success Measure of fitness If adapted to an optimal environment… Constant
11. Environmental heterogeneity @AliceTrevail • Uneven distribution of environmental characteristics
12. Environmental heterogeneity @AliceTrevail • Uneven distribution of environmental characteristics Resource distribution Community dynamics Behavioural response to temporal cycles
13. Environmental heterogeneity @AliceTrevail • Uneven distribution of environmental characteristics Resource distribution Community dynamics Behavioural response to temporal cycles • Universal feature – marine & terrestrial • Can capture multiple variables
14. Black-legged kittiwakes @AliceTrevail • Wide distribution • Chick rearing: short-ranging • Environmental indicator species
15. Black-legged kittiwakes @AliceTrevail 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 Island Bardsey Skomer St Martins Rathlin Colonsay Lambay
16. Black-legged kittiwakes @AliceTrevail 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 Island Bardsey Skomer St Martins Rathlin Colonsay Lambay Does environmental heterogeneity influence 1. Kittiwake foraging behaviour ? 2. Kittiwake reproductive success ?
17. Quantifying environmental heterogeneity @AliceTrevail 1. Environmental variables for spatial points • Bathymetry • Stratification • Front density, persistence & distance
18. Quantifying environmental heterogeneity @AliceTrevail 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
19. Quantifying environmental heterogeneity @AliceTrevail 1. Environmental variables for spatial points 2. Principal coordinate analysis 3. Heterogeneity = dispersion of points along principal coordinate axes Axis 1 Axis 2 Colony A Colony B Heterogeneous Homogeneous
20. Quantifying environmental heterogeneity @AliceTrevail 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
21. Results: Environmental heterogeneity @AliceTrevail • Environmental heterogeneity differed between colonies (p < 0.01) Heterogeneous Homogeneous 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 Principal coordinate analysis • First two axes explained 78.3% of the total variation
22. Results: Environmental heterogeneity • Environmental heterogeneity differed between colonies (p < 0.01) Heterogeneous Homogeneous 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 Muckle Skerry Copinsay Winnyfold Fowlsheugh Isle of May Coquet Filey Bempton Cliffs Puffin Island Bardsey Skomer St Martins Rathlin Colonsay Lambay Increasing heterogeneity @AliceTrevail
23. Results: Foraging behaviour • Environmental heterogeneity = longer trip duration (p < 0.05) @AliceTrevail 0 5 10 15 20 0.8 1.2 1.6 2.0 Environmental heterogeneity Mean trip duration (hr) p = 0.022, R2=0.15 No effect on Total distance Max distance 3-fold increase in duration across range of environmental heterogeneity
24. 0.5 1.0 Breeding success 0.8 1.2 1.6 2.0 Environmental heterogeneity Results: Reproductive success • Environmental heterogeneity = lower reproductive success (p < 0.001) @AliceTrevail p < 0.001, R2=0.35 70% decrease in success across range of environmental heterogeneity
25. 0.5 1.0 Breeding success 0.8 1.2 1.6 2.0 Environmental heterogeneity Results: Reproductive success • Environmental heterogeneity = lower reproductive success (p < 0.001) @AliceTrevail p < 0.001, R2=0.35 Resource acquisition more complex Greater foraging effort Poorer chick provisioning 70% decrease in success across range of environmental heterogeneity
26. Adaptations to the environment @AliceTrevail Environment Influences resource availability Foraging behaviour Allows animals to access resources Reproductive success Measure of fitness In summary… ? ?
27. Adaptations to the environment @AliceTrevail Environment Influences resource availability Foraging behaviour Allows animals to access resources Reproductive success Measure of fitness In summary… Yes
28. Adaptations to the environment @AliceTrevail Environment Influences resource availability Foraging behaviour Allows animals to access resources Reproductive success Measure of fitness In summary… Yes Yes
29. Summary • Populations show behavioural adaptation to environment • However, reproductive success related to environment conditions • Perhaps behavioural adaptations insufficient to buffer environmental differences @AliceTrevail
30. Thanks to… @AliceTrevail FAME project Many others for their help in the field
31. @AliceTrevail alice.trevail@Liverpool.ac.uk In brief: Environmental heterogeneity influences foraging behaviour & reduces breeding success Thank you for listening!
33. No link between success & trip duration 0.4 0.8 1.2 5 10 15 Trip Duration Breeding Success Multivariate analyses: covariation?