title: Geographical variation in body size and sexual size dimorphism in an Australian lizard, Boulenger's Skink (Morethia boulengeri).
abstract: Ecogeographical rules help explain spatial and temporal patterns in intraspecific body size. However, many of these rules, when applied to ectothermic organisms such as reptiles, are controversial and require further investigation. To explore factors that influence body size in reptiles, we performed a heuristic study to examine body size variation in an Australian lizard, Boulenger's Skink Morethia boulengeri from agricultural landscapes in southern New South Wales, south-eastern Australia. We collected tissue and morphological data on 337 adult lizards across a broad elevation and climate gradient. We used a model-selection procedure to determine if environmental or ecological variables best explained body size variation. We explored the relationship between morphology and phylogenetic structure before modeling candidate variables from four broad domains: (1) geography (latitude, longitude and elevation), (2) climate (temperature and rainfall), (3) habitat (vegetation type, number of logs and ground cover attributes), and (4) management (land use and grazing history). Broad phylogenetic structure was evident, but on a scale larger than our study area. Lizards were sexually dimorphic, whereby females had longer snout-vent length than males, providing support for the fecundity selection hypothesis. Body size variation in M. boulengeri was correlated with temperature and rainfall, a pattern consistent with larger individuals occupying cooler and more productive parts of the landscape. Climate change forecasts, which predict warmer temperature and increased aridity, may result in reduced lizard biomass and decoupling of trophic interactions with potential implications for community organization and ecosystem function.
authors.affiliation: Fenner School of Environment and Society, ARC Centre of Excellence for Environmental Decisions, and National Environment Research Program, The Australian National University, Canberra, Australia.
authors.forename: Damian R
authors.initials: DR
authors.lastname: Michael
authors.affiliation: Fenner School of Environment and Society, ARC Centre of Excellence for Environmental Decisions, and National Environment Research Program, The Australian National University, Canberra, Australia.
authors.forename: Sam C
authors.initials: SC
authors.lastname: Banks
authors.affiliation: Fenner School of Environment and Society, ARC Centre of Excellence for Environmental Decisions, and National Environment Research Program, The Australian National University, Canberra, Australia.
authors.forename: Maxine P
authors.initials: MP
authors.lastname: Piggott
authors.affiliation: Fenner School of Environment and Society, ARC Centre of Excellence for Environmental Decisions, and National Environment Research Program, The Australian National University, Canberra, Australia.
authors.forename: Ross B
authors.initials: RB
authors.lastname: Cunningham
authors.affiliation: Fenner School of Environment and Society, ARC Centre of Excellence for Environmental Decisions, and National Environment Research Program, The Australian National University, Canberra, Australia.
authors.forename: Mason
authors.initials: M
authors.lastname: Crane
authors.affiliation: Fenner School of Environment and Society, ARC Centre of Excellence for Environmental Decisions, and National Environment Research Program, The Australian National University, Canberra, Australia.
authors.forename: Christopher
authors.initials: C
authors.lastname: MacGregor
authors.affiliation: Fenner School of Environment and Society, ARC Centre of Excellence for Environmental Decisions, and National Environment Research Program, The Australian National University, Canberra, Australia.
authors.forename: Lachlan
authors.initials: L
authors.lastname: McBurney
authors.affiliation: Fenner School of Environment and Society, ARC Centre of Excellence for Environmental Decisions, and National Environment Research Program, The Australian National University, Canberra, Australia.
authors.forename: David B
authors.initials: DB
authors.lastname: Lindenmayer
mesh_terms: D000818:Animals; D049628:Body Size / Q000502:physiology*; D002980:Climate; D017753:Ecosystem; D005260:Female; D005843:Geography; D008116:Lizards / Q000033:anatomy & histology* / Q000502:physiology; D008297:Male; D010802:Phylogeny; D012727:Sex Characteristics; D013021:South Australia