The influence of temperature seasonality on elevational range size across latitude: a test using Liolaemus lizards

SHELDON K; LEACHE A; CRUZ FB

Global Ecology and Biogeography

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2015 vol. 24 p. 632 - 641

1466-822X

ABSTRACTAim Identifying factors that limit species distributions is a fundamental questionin ecology with implications for understanding global biodiversity patterns andspecies responses to environmental change. Theory suggests that temperature seasonalitymay affect range size. Species at higher latitudes and elevations experiencegreater temperature variation, which should lead to broader thermal tolerances andelevational ranges. Research suggests that realized seasonality, or the seasonalityspecies experience when active, may be a better predictor of distributions thanannual seasonality.We tested the seasonality hypothesis by examining relationshipsbetween environmental factors and elevational range.Location Argentina.Methods We gathered data on ecology and thermal physiology for 33 Liolaemuslizards (Liolaemidae) and analysed data in phylogenetic comparative analyses usingmitochondrial DNA sequences.We used 1000 tree structures and ran phylogeneticgeneralized least squares analyses on all 33 species and on 23 species in theboulengeri clade to determine if the elevational range of lizards shows a positiverelationship with annual and realized seasonality, thermal tolerance, latitude andelevational midpoint of the species distribution.Results Latitude and elevational midpoint were good predictors of elevationalrange in all models.Annual seasonality was a good predictor of elevational range inmodels containing 33 species.Variation in phylogenetic tree structure led to differencesin the best-fit statistical models. Thermal tolerance and realized seasonalitywere not good indicators of elevational range.Main conclusions Our findings support some, but not all, of the predictions ofthe seasonality hypothesis. Species at higher latitudes and elevations have largerelevational ranges, and annual seasonality is partly responsible for this increase.Yet,adult thermal tolerance shows no relationship with elevational range, suggestingthat distributions may depend on the physiology of other Liolaemus life stages.Differences in phylogenetic tree structure and the number of species included inanalyses can lead to different conclusions regarding the seasonality hypothesis.