Pushing boundaries of range and resilience: a review of range-extension by a barrens-forming sea urchin

• Main Author: Ling, SD
• Format: Text
• Language: English
• Published: Universidad de La Laguna 2012
• Subjects: Biological Sciences; Ecology; Marine and Estuarine Ecology (incl. Marine Ichthyology); Antarc*
• Online Access: http://ecite.utas.edu.au/80090

Pushingboundariesofrangeandresilience:areviewofrange-‐extensionbyabarrens-‐formingseaurchinScottD.Ling,InstituteforMarine&AntarcticStudies,UniversityofTasmania,Hobart.Tas.7001,Australia;email:[e-mail]-‐formingseaurchinCentrostephanusrodgersii(Diadematidae)hasundergonerecentpolewardrange-‐extensiontotheTasmaniancoastline(SEAustralia).Bycompilingfieldobservations(includingSSTspanning>60yrs),broad-‐scalesurveysandmanipulativeexperimentsconductedduringthepastdecade,thisreviewdetailsknowledgeontheresponseofthiskeyseaurchinspeciestoclimatechangeandduallyexploresmultipleprocessesinfluencingtheultimateecologicalconsequenceofcatastrophic-‐shiftfromproductivekelpbedstourchinbarrens,asnowobservedwithintherange-‐extensionregion.Asaresultofchangingregionalclimate,easternTasmaniahasbecomeincreasinglysuitableforCentrostephanuslarvaldevelopmentwiththetimingoftheseaurchinsarrival,age-‐structureandspatialdistributionacrosstheextension-‐regionconsistentwithpatternsinwarmingseatemperaturesandcurrent-‐drivendispersalpotential.Furthermore,consistencyintemperaturedependencyoflarvaldevelopmentpluslackofgeneticdifferentiationofthespeciesacrossitsentirerange,confirmthecriticalroleofchangingclimateindrivingtherange-‐extension.Continuedwarmingpredictedforthisregionwillfavourincreasedlarvalsurvival,promotingongoingpopulationexpansionandultimatelyincreasedlikelihoodofpopulationsreachingsufficientdensitytoaffectwidespreadovergrazing.Assuch,knowledgeofpatternsandmechanismspromotingovergrazingarealsoreviewedforthepurposeofidentifyingkelpbedsatgreatestriskgivenclimatetrends,reefsubstratumtypesandpredatorabundance(chieflyspinylobsters)asinfluencedbyintensefishingpressure.Finally,thisreviewshowshowmanagementofnon-‐climaticlocalscalestressorscanbeusedtoincreaseresilienceofkelpbedsagainstovergrazinggivenlarge-‐scaleclimate-‐drivenincreasesinkeyseaurchinpopulations.