Environmental drivers of movement in a threatened seabird: insights from a mechanistic model and implications for conservation

Frankish, Caitlin K., Phillips, Richard A., Clay, Thomas A., Somveille, Marius ORCID: https://orcid.org/0000-0002-6868-5080 and Manica, Andrea (2020) Environmental drivers of movement in a threatened seabird: insights from a mechanistic model and implications for conservation. Diversity and Distributions, 26 (10). pp. 1315-1329. ISSN 1366-9516

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Abstract

Aim: Determining the drivers of movement of different life-history stages is crucial for understanding age-related changes in survival rates and, for marine top predators, the link between fisheries overlap and incidental mortality (bycatch), which is driving population declines in many taxa. Here, we combine individual tracking data and a movement model to investigate the environmental drivers and conservation implications of divergent movement patterns in juveniles (fledglings) and adults of a threatened seabird, the white-chinned petrel (Procellaria aequinoctialis). Location: South-west Atlantic Ocean. Methods: We compare the spatial distributions and movement characteristics of juvenile, breeding and non-breeding adult petrels, and apply a mechanistic movement model to investigate the extent to which chlorophyll a concentrations (a proxy for food resources) and ocean surface winds drive their divergent distribution patterns. We also consider the conservation implications by determining the relative overlap of each life-history stage with fishing intensity and reported fishing effort (proxies for bycatch risk). Results: Naïve individuals fledged with similar flight capabilities (based on distances travelled, flight speeds and track sinuosity) to adults but differed in their trajectories. Comparison of simulations from the mechanistic model with real tracks showed that juvenile movements are best predicted by prevailing wind patterns, whereas adults are attracted to food resources on the Patagonian Shelf. The juveniles initially dispersed to less productive oceanic waters than those used by adults, and overlapped less with fishing activity; however, as they moved westwards towards South America, bycatch risk increased substantially. Main conclusions: The use of a mechanistic framework provided insights into the ontogeny of movement strategies within the context of learned versus innate behaviour and demonstrated that divergent movement patterns of adults and juveniles can have important implications for the conservation of threatened seabirds.

Item Type:	Article
Additional Information:	Funding Information: This study represents a contribution to the Ecosystems component of the British Antarctic Survey Polar Science for Planet Earth Programme, funded by NERC. The tracking devices were funded by the Government of South Georgia and the South Sandwich Islands (GSGSSI). CFK was supported by a studentship co‐funded by NERC (Grant Number: NE/L002507/1) and GSGSSI, with CASE funding from the Royal Society for the Protection of Birds (RSPB).
Uncontrolled Keywords:	fisheries bycatch mitigation,juvenile,mechanistic movement model,ontogeny,seabirds,tracking,ecology, evolution, behavior and systematics,sdg 14 - life below water ,/dk/atira/pure/subjectarea/asjc/1100/1105
Faculty \ School:	Faculty of Science > School of Environmental Sciences
UEA Research Groups:	Faculty of Science > Research Centres > Centre for Ecology, Evolution and Conservation
Related URLs:	http://www.scopus.com/inward/record.url?...
Depositing User:	LivePure Connector
Date Deposited:	22 Jul 2024 10:32
Last Modified:	09 Oct 2024 13:40
URI:	https://ueaeprints.uea.ac.uk/id/eprint/95979
DOI:	10.1111/ddi.13130

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