Metapopulation Tracking Juvenile Penguins Reveals an Ecosystem-wide Ecological Trap

• DOI: 10.1016/j.cub.2016.12.054
• Publication Date: 2017-02-09T21:03:10Z
• Authors: Richard B. Sherley; Katrin Ludynia; Bruce M. Dyer; Tarron Lamont; Azwianewi B. Makhado; Jean-Paul Roux; Kylie L. Scales; Les G. Underhill; Stephen C. Votier
• Keywords: Forage fish; Metapopulation; Marine ecosystem; Nursery habitat; Seascape

Climate change and fisheries are transforming the oceans, but we lack a complete understanding of their ecological impact [1McCauley D.J. Pinsky M.L. Palumbi S.R. Estes J.A. Joyce F.H. Warner R.R. Marine defaunation: animal loss in global ocean.Science. 2015; 347: 1255641-1255647Crossref PubMed Scopus (735) Google Scholar, 2Sydeman W.J. Poloczanska E. Reed T.E. Thompson S.A. marine vertebrates.Science. 350: 772-777Crossref (147) 3Hobday A.J. Bell J.D. Cook T.R. Gasalla M.A. Weng K.C. Reconciling conflicts pelagic under climate change.Deep Sea Res. Part II Top. Stud. Oceanogr. 113: 291-300Crossref (24) Scholar]. Environmental degradation can cause maladaptive habitat selection, inducing traps with profound consequences for biodiversity [4Fletcher Jr., R.J. Orrock J.L. Robertson B.A. How type anthropogenic alters traps.Proc. Biol. Sci. 2012; 279: 2546-2552Crossref (69) 5Robertson Rehage J.S. Sih A. Ecological novelty emergence evolutionary traps.Trends Ecol. Evol. 2013; 28: 552-560Abstract Full Text PDF (283) 6Hale R. Treml E.A. Swearer S.E. Evaluating metapopulation 282: 20142930Crossref (63) However, whether operate systems is unclear [7Hale traps: current evidence future directions.Proc. 2016; 283: 20152647Crossref (153) Large vertebrates may be vulnerable to [6Hale Scholar], broad-scale movements complex life histories obscure population-level selection [8Runge C.A. Martin T.G. Possingham H.P. Willis S.G. Fuller R.A. Conserving mobile species.Front. Environ. 2014; 12: 395-402Crossref (303) 9Hays G.C. Ferreira L.C. Sequeira A.M.M. Meekan M.G. Duarte C.M. Bailey H. Bailleul F. Bowen W.D. Caley M.J. Costa D.P. et al.Key questions megafauna movement ecology.Trends 31: 463-475Abstract (322) We satellite tracked postnatal dispersal African penguins (Spheniscus demersus) from eight sites across breeding range test they have become ecologically trapped degraded Benguela ecosystem. Bayesian state-space models show that traversed thousands square kilometers areas low sea surface temperatures (14.5°C–17.5°C) high chlorophyll-a (∼11 mg m−3). These were once reliable cues prey-rich waters, industrial fishing depleted forage fish stocks this system [10Grémillet D. Lewis S. Drapeau L. van der Lingen C.D. Huggett Coetzee J.C. Verheye H.M. Daunt Wanless Ryan P.G. Spatial match-mismatch upwelling zone: should expect chlorophyll sea-surface temperature predict predator distributions?.J. Appl. 2008; 45: 610-621Crossref (189) 11Roux J.-P. Gibbons Moroff N. Shannon L.J. Smith A.D. Cury P.M. Jellyfication ecosystems as consequence overfishing small fish: lessons Benguela.Bull. Mar. 89: 249-284Crossref (94) Juvenile penguin survival populations selecting areas, projection suggest numbers ∼50% lower than if non-impacted habitats used, revealing extent effect trap first time. cascading impacts localized depletion—unobserved studies on adults—were only elucidated via demographic data juveniles. Our results support suspending when prey biomass drops below critical thresholds [12Pikitch E.K. Stop-loss order fisheries.Proc. Natl. Acad. USA. 112: 6529-6530Crossref (13) 13Essington Moriarty P.E. Froehlich H.E. Hodgson E.E. Koehn L.E. Oken K.L. Siple M.C. Stawitz C.C. Fishing amplifies population collapses.Proc. 6648-6652Crossref (187) Scholar] mitigation will require matching conservation action scale processes [14Boyd C. Brooks T.M. Butchart S.H.M. Edgar G.J. Da Fonseca G.A.B. Hawkins Hoffmann M. Sechrest W. Stuart S.N. Dijk P.P. threatened species.Conserv. Lett. 1: 37-43Crossref