title: Sensitivity of leaf size and shape to climate: global patterns and paleoclimatic applications.
abstract: • Paleobotanists have long used models based on leaf size and shape to reconstruct paleoclimate. However, most models incorporate a single variable or use traits that are not physiologically or functionally linked to climate, limiting their predictive power. Further, they often underestimate paleotemperature relative to other proxies. • Here we quantify leaf-climate correlations from 92 globally distributed, climatically diverse sites, and explore potential confounding factors. Multiple linear regression models for mean annual temperature (MAT) and mean annual precipitation (MAP) are developed and applied to nine well-studied fossil floras. • We find that leaves in cold climates typically have larger, more numerous teeth, and are more highly dissected. Leaf habit (deciduous vs evergreen), local water availability, and phylogenetic history all affect these relationships. Leaves in wet climates are larger and have fewer, smaller teeth. Our multivariate MAT and MAP models offer moderate improvements in precision over univariate approaches (± 4.0 vs 4.8°C for MAT) and strong improvements in accuracy. For example, our provisional MAT estimates for most North American fossil floras are considerably warmer and in better agreement with independent paleoclimate evidence. • Our study demonstrates that the inclusion of additional leaf traits that are functionally linked to climate improves paleoclimate reconstructions. This work also illustrates the need for better understanding of the impact of phylogeny and leaf habit on leaf-climate relationships.
authors.affiliation: Department of Earth and Environmental Sciences, Wesleyan University, Middletown, CT 06459, USA. daniel_peppe@baylor.edu
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Peppe
authors.forename: Dana L
authors.initials: DL
authors.lastname: Royer
authors.forename: Bárbara
authors.initials: B
authors.lastname: Cariglino
authors.forename: Sofia Y
authors.initials: SY
authors.lastname: Oliver
authors.forename: Sharon
authors.initials: S
authors.lastname: Newman
authors.forename: Elias
authors.initials: E
authors.lastname: Leight
authors.forename: Grisha
authors.initials: G
authors.lastname: Enikolopov
authors.forename: Margo
authors.initials: M
authors.lastname: Fernandez-Burgos
authors.forename: Fabiany
authors.initials: F
authors.lastname: Herrera
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Adams
authors.forename: Edwin
authors.initials: E
authors.lastname: Correa
authors.forename: Ellen D
authors.initials: ED
authors.lastname: Currano
authors.forename: J Mark
authors.initials: JM
authors.lastname: Erickson
authors.forename: Luis Felipe
authors.initials: LF
authors.lastname: Hinojosa
authors.forename: John W
authors.initials: JW
authors.lastname: Hoganson
authors.forename: Ari
authors.initials: A
authors.lastname: Iglesias
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Jaramillo
authors.forename: Kirk R
authors.initials: KR
authors.lastname: Johnson
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Jordan
authors.forename: Nathan J B
authors.initials: NJ
authors.lastname: Kraft
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Lovelock
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Lusk
authors.forename: Ulo
authors.initials: U
authors.lastname: Niinemets
authors.forename: Josep
authors.initials: J
authors.lastname: Peñuelas
authors.forename: Gillian
authors.initials: G
authors.lastname: Rapson
authors.forename: Scott L
authors.initials: SL
authors.lastname: Wing
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Wright
mesh_terms: D002138:Calibration; D002980:Climate; D005580:Fossils; D005843:Geography; D038622:Internationality; D008954:Models, Biological; D009929:Organ Size; D010163:Paleontology; D010802:Phylogeny; D018515:Plant Leaves / Q000033:anatomy & histology*; D011891:Rain; D012044:Regression Analysis; D013045:Species Specificity; D013696:Temperature