title: Population dynamics can be more important than physiological limits for determining range shifts under climate change.
abstract: Evidence is accumulating that species' responses to climate changes are best predicted by modelling the interaction of physiological limits, biotic processes and the effects of dispersal-limitation. Using commercially harvested blacklip (Haliotis rubra) and greenlip abalone (Haliotis laevigata) as case studies, we determine the relative importance of accounting for interactions among physiology, metapopulation dynamics and exploitation in predictions of range (geographical occupancy) and abundance (spatially explicit density) under various climate change scenarios. Traditional correlative ecological niche models (ENM) predict that climate change will benefit the commercial exploitation of abalone by promoting increased abundances without any reduction in range size. However, models that account simultaneously for demographic processes and physiological responses to climate-related factors result in future (and present) estimates of area of occupancy (AOO) and abundance that differ from those generated by ENMs alone. Range expansion and population growth are unlikely for blacklip abalone because of important interactions between climate-dependent mortality and metapopulation processes; in contrast, greenlip abalone should increase in abundance despite a contraction in AOO. The strongly non-linear relationship between abalone population size and AOO has important ramifications for the use of ENM predictions that rely on metrics describing change in habitat area as proxies for extinction risk. These results show that predicting species' responses to climate change often require physiological information to understand climatic range determinants, and a metapopulation model that can make full use of this data to more realistically account for processes such as local extirpation, demographic rescue, source-sink dynamics and dispersal-limitation.
authors.affiliation: The Environment Institute, School of Earth and Environmental Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia.
authors.forename: Damien A
authors.initials: DA
authors.lastname: Fordham
authors.forename: Camille
authors.initials: C
authors.lastname: Mellin
authors.forename: Bayden D
authors.initials: BD
authors.lastname: Russell
authors.forename: Reşit H
authors.initials: RH
authors.lastname: Akçakaya
authors.forename: Corey J A
authors.initials: CJ
authors.lastname: Bradshaw
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Aiello-Lammens
authors.forename: Julian M
authors.initials: JM
authors.lastname: Caley
authors.forename: Sean D
authors.initials: SD
authors.lastname: Connell
authors.forename: Stephen
authors.initials: S
authors.lastname: Mayfield
authors.forename: Scoresby A
authors.initials: SA
authors.lastname: Shepherd
authors.forename: Barry W
authors.initials: BW
authors.lastname: Brook
mesh_terms: D000818:Animals; D001315:Australia; D057231:Climate Change; D049851:Gastropoda / Q000502:physiology*; D008962:Models, Theoretical; D011156:Population Density; D011157:Population Dynamics
keywords: abalone; demographic processes; ecological niche model; extinction risk; marine biodiversity conservation; marine species distribution model; mechanistic model; metapopulation dynamics; population viability analysis; source-sink dynamics