title: Loss of thermal refugia near equatorial range limits.
abstract: This study examines the importance of thermal refugia along the majority of the geographical range of a key intertidal species (Patella vulgata Linnaeus, 1758) on the Atlantic coast of Europe. We asked whether differences between sun-exposed and shaded microhabitats were responsible for differences in physiological stress and ecological performance and examined the availability of refugia near equatorial range limits. Thermal differences between sun-exposed and shaded microhabitats are consistently associated with differences in physiological performance, and the frequency of occurrence of high temperatures is most probably limiting the maximum population densities supported at any given place. Topographical complexity provides thermal refugia throughout most of the distribution range, although towards the equatorial edges the magnitude of the amelioration provided by shaded microhabitats is largely reduced. Importantly, the limiting effects of temperature, rather than being related to latitude, seem to be tightly associated with microsite variability, which therefore is likely to have profound effects on the way local populations (and consequently species) respond to climatic changes.
authors.affiliation: CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, Vairão, 4485-661, Portugal.
authors.forename: Fernando P
authors.initials: FP
authors.lastname: Lima
authors.affiliation: CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, Vairão, 4485-661, Portugal.
authors.forename: Filipa
authors.initials: F
authors.lastname: Gomes
authors.affiliation: CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, Vairão, 4485-661, Portugal.|Departamento de Biologia, Faculdade de Ciências da, Universidade do Porto, R. Campo Alegre, s/n, Porto, 4169-007, Portugal.
authors.forename: Rui
authors.initials: R
authors.lastname: Seabra
authors.affiliation: Department of Biological Sciences, University of South Carolina, Columbia, SC, 29208, USA.
authors.forename: David S
authors.initials: DS
authors.lastname: Wethey
authors.affiliation: MARE - Marine and Environmental Sciences Centre, Laboratório de Ciências do Mar (CIEMAR), Universidade de Évora, Avenida Vasco da Gama, Apartado 190, Sines, 7520-903, Portugal.
authors.forename: Maria I
authors.initials: MI
authors.lastname: Seabra
authors.affiliation: MARE - Marine and Environmental Sciences Centre, Laboratório de Ciências do Mar (CIEMAR), Universidade de Évora, Avenida Vasco da Gama, Apartado 190, Sines, 7520-903, Portugal.|Departamento de Biologia, Universidade de Évora, Évora, 7002-554, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Cruz
authors.affiliation: Departamento de Biologia, Faculdade de Ciências da, Universidade do Porto, R. Campo Alegre, s/n, Porto, 4169-007, Portugal.
authors.forename: António M
authors.initials: AM
authors.lastname: Santos
authors.affiliation: Department of Biological Sciences, University of South Carolina, Columbia, SC, 29208, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Hilbish
mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D001831:Body Temperature; D017753:Ecosystem; D005060:Europe; D049851:Gastropoda / Q000502:physiology*; D005843:Geography; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis; D000068236:Refugium; D013312:Stress, Physiological; D013472:Sunlight; D013696:Temperature
chemical_list: D018840:HSP70 Heat-Shock Proteins
keywords: biogeography; heat shock proteins; intertidal; microhabitat; thermal refugia; thermal stress