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Defining ecologically-relevant scales for spatial protection using long-term data on an endangered seabird and local prey availability

, , , , , , , ,
1 Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, United Kingdom
2 Animal Demography Unit, University of Cape Town, Cape Town, South Africa
3 Percy FitzPatrick Institute, University of Cape Town, Cape Town, South Africa
4 Marine Research Institute, University of Cape Town, Cape Town, South Africa
5 Department of Agriculture, Forestry and Fisheries, Cape Town, South Africa
6 Department of Environmental Affairs, Cape Town, South Africa
7 Institute of Ecology and Environmental Sciences, Université Pierre et Marie Curie (Paris VI), Paris, France
DOI
10.7287/peerj.preprints.2122v1
Published
Accepted
Subject Areas
Conservation Biology, Ecology, Marine Biology
Keywords
Benguela upwelling ecosystem, Jasus lalandii, Phalacrocorax neglectus, rock lobster, marine protected areas, seabird conservation, marine spatial planning
Copyright
© 2016 Sherley et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
Cite this article
Sherley RB, Botha P, Underhill LG, Ryan PG, van Zyl D, Cockcroft AC, Crawford RJ, Dyer BM, Cook TR. 2016. Defining ecologically-relevant scales for spatial protection using long-term data on an endangered seabird and local prey availability. PeerJ Preprints 4:e2122v1

Abstract

Human activities are important drivers of marine ecosystem functioning. However, teasing apart the synergistic effects of fishing and environmental variability on the prey base of non-target predators is difficult, often because estimates of prey availability on appropriate scales are lacking. Hence, understanding the links between direct measures of prey abundance and population change can help integrate the needs of non-target predators into fisheries management. Here we investigated the local population response (number of breeders) of bank cormorants Phalacrocorax neglectus, an Endangered seabird, to the availability of its prey, the heavily-fished West Coast rock lobster Jasus lalandii. Using Bayesian state-space modelled counts of cormorants at three colonies, 22 years of fisheries-independent data on local lobster abundance and generalized additive modelling, we determined the spatial-scale pertinent to these relationships in areas of differing lobster abundance. Cormorant numbers responded positively to rock lobster availability in the regions of intermediate and high abundance, but not where regime shifts and fishing pressure have made rock lobster scarce. However, the spatial scale (30 km) at which the relationships were strongest was greater than the cormorants’ foraging range when breeding. Prey availability in the non-breeding season, prey switching and prey ecology can all influence neritic seabirds and should be considered in marine spatial planning. Crucially, though, our results highlight the potential for small-scale marine protected areas (MPAs) to benefit top predators over their full-life cycle by protecting their prey. Precautionary implementation of MPAs, with robust assessment and adaptive-management, could protect predators and their prey without negatively impacting dependent fisheries.

Author Comment

This is a preprint submission to PeerJ Preprints. The manuscript is to be submitted to Conservation Biology.

Supplemental Information

Appendix S1: State-space model code

DOI: 10.7287/peerj.preprints.2122v1/supp-1

Appendix S2: Additional Figures

DOI: 10.7287/peerj.preprints.2122v1/supp-2

Appendix S3: Full candidate model set and model selection results

DOI: 10.7287/peerj.preprints.2122v1/supp-3

Additional Information

Competing Interests

The authors declare that they have no competing interests.

Author Contributions

Richard B Sherley conceived and designed the experiments, analyzed the data, wrote the paper, prepared figures and/or tables, reviewed drafts of the paper.

Philna Botha analyzed the data, wrote the paper, reviewed drafts of the paper.

Les G Underhill analyzed the data, reviewed drafts of the paper.

Peter G Ryan reviewed drafts of the paper.

Danie van Zyl performed the experiments, reviewed drafts of the paper.

Andrew C Cockcroft performed the experiments, reviewed drafts of the paper.

Robert JM Crawford performed the experiments, reviewed drafts of the paper.

Bruce M Dyer performed the experiments, reviewed drafts of the paper.

Timothée R Cook conceived and designed the experiments, analyzed the data, wrote the paper, prepared figures and/or tables, reviewed drafts of the paper.

Animal Ethics

The following information was supplied relating to ethical approvals (i.e., approving body and any reference numbers):

The work involving vertebrate animals (counts of birds) was conducted by staff of the South African Government's Department of Environmental Affairs (the relevant permitting authority) and approved by their Animal Ethics Board.

Field Study Permissions

The following information was supplied relating to field study approvals (i.e., approving body and any reference numbers):

The field data were collected by the co-authors from the South African Government's Department of Environmental Affairs and Department of Agriculture, Forestry and Fisheries (the relevant permitting authorities).

Data Deposition

The following information was supplied regarding data availability:

Plots of the bank cormorant count data and rock lobster data are including in the manuscript. Code to fit the state-space model is included in the supplementary materials. All raw data are held in repositories of the South African government and are free-available upon request.

Funding

Funding was provided by the National Research Foundation (NRF), through its SEAChange Programme (Grant Number: 79735) and an incentive grant to RJMC, the Leiden Conservation Foundation (RBS), the Claude Leon Foundation (TRC). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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Defining ecologically-relevant scales for spatial protection using long-term data on an endangered seabird and local prey availability
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