title: The value of crossdating to retain high-frequency variability, climate signals, and extreme events in environmental proxies.
abstract: High-resolution biogenic and geologic proxies in which one increment or layer is formed per year are crucial to describing natural ranges of environmental variability in Earth's physical and biological systems. However, dating controls are necessary to ensure temporal precision and accuracy; simple counts cannot ensure that all layers are placed correctly in time. Originally developed for tree-ring data, crossdating is the only such procedure that ensures all increments have been assigned the correct calendar year of formation. Here, we use growth-increment data from two tree species, two marine bivalve species, and a marine fish species to illustrate sensitivity of environmental signals to modest dating error rates. When falsely added or missed increments are induced at one and five percent rates, errors propagate back through time and eliminate high-frequency variability, climate signals, and evidence of extreme events while incorrectly dating and distorting major disturbances or other low-frequency processes. Our consecutive Monte Carlo experiments show that inaccuracies begin to accumulate in as little as two decades and can remove all but decadal-scale processes after as little as two centuries. Real-world scenarios may have even greater consequence in the absence of crossdating. Given this sensitivity to signal loss, the fundamental tenets of crossdating must be applied to fully resolve environmental signals, a point we underscore as the frontiers of growth-increment analysis continue to expand into tropical, freshwater, and marine environments.
authors.affiliation: Marine Science Institute, University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX, 78373, USA.
authors.forename: Bryan A
authors.initials: BA
authors.lastname: Black
authors.affiliation: Department of Geography, Environment, and Society, University of Minnesota, Geography Room 414, Minneapolis, MN, 55455, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Griffin
authors.affiliation: Marine Science Institute, University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX, 78373, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: van der Sleen
authors.affiliation: Department of Geological and Atmospheric Sciences, Iowa State University, 12 Science I, Ames, IA, 50011, USA.
authors.forename: Alan D
authors.initials: AD
authors.lastname: Wanamaker
authors.affiliation: Department of Earth and Environmental Systems, Indiana State University, Science 159E, Terre Haute, IN, 47809, USA.
authors.forename: James H
authors.initials: JH
authors.lastname: Speer
authors.affiliation: Swiss Federal Research Institute WSL, Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland.|Oeschger Centre for Climate Change Research, University of Bern, Zähringerstrasse 25, CH-3012, Bern, Switzerland.
authors.forename: David C
authors.initials: DC
authors.lastname: Frank
authors.affiliation: Department of Geosciences, University of Arkansas, 216 Ozark Hall, Fayetteville, AR, 72701, USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Stahle
authors.affiliation: Harvard Forest, 324 N Main St., Petersham, MA, 10366, USA.
authors.forename: Neil
authors.initials: N
authors.lastname: Pederson
authors.affiliation: Department of Forest Resources and Environmental Conservation, Virginia Tech, 228C Cheatham Hall, Blacksburg, VA, 24061, USA.
authors.forename: Carolyn A
authors.initials: CA
authors.lastname: Copenheaver
authors.affiliation: Laboratory of Tree-Ring Research, University of Arizona, 1215 E. Lowell St., Tucson, AZ, 85721, USA.
authors.forename: Valerie
authors.initials: V
authors.lastname: Trouet
authors.affiliation: Department of Geological and Atmospheric Sciences, Iowa State University, 12 Science I, Ames, IA, 50011, USA.
authors.forename: Shelly
authors.initials: S
authors.lastname: Griffin
authors.affiliation: School of Biological Sciences & Environment Institute, University of Adelaide, Darling Building, Adelaide, SA, 5005, Australia.
authors.forename: Bronwyn M
authors.initials: BM
authors.lastname: Gillanders
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000254:growth & development; D002980:Climate; D004463:Ecology / Q000379:methods*; D005399:Fishes / Q000254:growth & development; D005618:Fresh Water; D014197:Trees / Q000254:growth & development
keywords: climate reconstruction; crossdating; dendrochronology; global change; paleoclimate; sclerochronology