Environmental constraints on seabird energetics across spatiotemporal scales

PhD research (2020 - Date)

Supervised by Amanda Bates, Dave Fifield and Shawn Leroux

My doctoral research aims to answer the overarching question: how does environmental change constrain seabird energetics across multiple levels of biological organization? Through coupling fieldwork with long-term timeseries and powerful modelling frameworks (e.g., Niche Mapper, Dynamic Energy Budget Modelling), I hope to expose the species, populations, communities, and ecosystems with the greatest energetic limitations to past and future environmental change. This research will provide clear recommendations for how environmental decision-makers can integrate the ecophysiological requirements of biological levels into management actions for practical real-world outcomes.

The link between seabird traits and anthropogenic threats 

MSc research (2018 - 2020)

Supervised by Amanda Bates, Dave Fifield and Shawn Leroux

Collaborators: Robert Cooke, Diana Bowler and Kristina Boerder

Seabirds are heavily threatened by anthropogenic activities and their conservation status is deteriorating rapidly. Key goals for successful management and conservation are to identify vulnerable species, and to evaluate conservation gains. Here, we couple a comprehensive dataset of traits with International Union for Conservation of Nature (IUCN) Red List extinction risk categories, and threat data for all 341 seabird species. We reveal seabirds segregate in trait space based on threat status, and anthropogenic impacts are selectively removing large, long-lived, pelagic surface feeders with small habitat breadths. Furthermore, we quantify species’ vulnerability to longline, trawl and purse seine bycatch, and find bycatch mitigation could successfully conserve species’ traits and ecosystem functions at a global scale. Our results suggest that targeted conservation strategies must be implemented to ensure a functionally similar suite of seabirds will not be lost in the near future.

Associated Publications

Richards, C., Cooke, R. S. C. & Bates, A. E. (2021) 'Biological traits of seabirds predict extinction risk and vulnerability to anthropogenic threats', Global Ecology and Biogeography, 00: 1– 14.

Richards, C., Cooke, R. S. C., Bowler, D., Boerder, K. & Bates, A. E. (in prep) ‘Bycatch mitigation could prevent significant shifts in seabird traits across the globe’, intended journal: Biological Conservation.

Richards, C., Cooke, R. S. C., Bowler, D., Boerder, K. & Bates, A. E. (in prep) ‘Species’ traits and exposure as a future lens for quantifying seabird bycatch vulnerability in global fisheries’, intended journal: Avian Conservation & Ecology.

Manx shearwater rafting behaviour around Skomer Island

BSc research (2016 - 2017)

Supervised by Amanda Bates

Collaborators: Oliver Padget, Tim Guilford, Oxford Navigation Group

Before visiting or leaving their remote island colonies, seabirds often engage in a behaviour termed "rafting", where birds sit, often in groups, on the water close to the colony. Despite rafting being a widespread behaviour across many seabird taxa, the functional significance of rafting remains unknown. Here we combine global positioning system (GPS) tracks, observational and wind condition data to investigate correlates of rafting behaviour in Manx shearwaters (Puffinus puffinus) at a large colony on Skomer Island, Wales. We test (1) the influence of wind direction on rafting location and (2) whether raft size changes with respect to wind speed. Our approach further allows us to describe day-night trends in (3) raft distance from shore through time; (4) the number of birds present in the nearshore waters through time; and (5) spatial patterns of Manx shearwater rafts in marine waters adjacent to the breeding colony. We find no evidence that wind direction, for our study period, influences Manx shearwater rafting location, yet raft size marginally increases on windier days. We further find rafting birds closer to the shore at night than during the day. Thus, before sunset, birds form a "halo'' around Skomer Island, but this halo disappears during the night as more individuals return from foraging trips and raft nearer the colony on Skomer Island. The halo pattern reforms before sunrise as rafts move away from land and birds leave for foraging. Our results suggest that wind conditions may not be as ecologically significant for rafting locations as previously suspected, but rafting behaviour may be especially important for avoiding predators and cleaning feathers.

Associated Publications

Richards, C., Padget, O., Guilford, T. & Bates, A. E. (2019) ‘Manx shearwater (Puffinus puffinus) rafting behaviour revealed by GPS-tracking and behavioural observations’, PeerJ , 7:e7863.

[Editors' Pick]

All content © Cerren Richards 2020

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