An alternative approach to transfer functions? Testing the performance of a functional trait-based model for testate amoeba

F ALAYNE STREET-PERROTT,; PAUL DM HUGHES,; DMITRI MAUQUOY,; EMMA M RICE,; TIM J DALEY,; PAYNE R.,; PANCOTTO V,; NEIL J LOADER,; THOMAS P ROLAND,; VAN BELLEN, SIMON

PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017 vol. 468 p. 173 - 183

0031-0182

Transfer functions are now widely available to infer past environmental conditions from biotic assemblages. Existing transfer functions are based on species assemblages but an alternative is to characterize assemblages based on functional traits, characteristics of the organism which determine its fitness and performance. Here, we test the potential of trait-based transfer functions using testate amoeba functional traits to reconstruct peatland water-table depths. A total of seven functional traits with linkages to peat moisture content were identified and quantified as communityweighted- means for each of 43 taxa in a training set fromTierra del Fuego, South America. Transfer functions based on (multiple) linear regression and partial least-squares were produced, validated using crossvalidation and an independent test set, and applied to three core records. Trait-based models performed remarkablywell. Model performance based on cross-validation and an independent test setwas only marginallyweaker than for models based on species and reconstructed down-core trends were extremely similar. Trait-based models offer considerable potential for paleoecological reconstruction particularly in no-analogue situations, where no species transfer function is available and for inexperienced analysts. The approach deserves further validation and testing for both testate amoebae and other groups of microfossils.