Palaeogeography, Palaeoclimatology, Palaeoecology 159 (2000) 313--347

• Main Authors: Www Elsevier Nl, Brigitta Ammanna, H. J. B. Birks B, Stephen J. Brooksd, Ulrich Eichere, Ulrich Von Grafenstein F, Wolfgang Hofmann G, Geoffrey Lemdahl H, Jakob Schw, Kazimierz Tobolski I, Lucia Wick A
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2000
• Subjects: ice core
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.9.1130; http://www.climate.unibe.ch/~jakob/publications/ammann_synthesis2000.pdf

To assess the presence or absence of lags in biotic responses to rapid climatic changes, we: (1) assume that the d18O in biogenically precipitated carbonates record global or hemispheric climatic change at the beginning and at the end of the Younger Dryas without any lag at our two study sites of Gerzensee and Leysin, Switzerland; (2) derive a time scale by correlating the d18O record from these two sites with the d18O record of the GRIP ice core; (3) measure d18O records in ostracods and molluscs to check the record in the bulk samples and to detect possible hydrological changes; (4) analyse at Gerzensee and Leysin as well as at two additional sites (that lack carbonates and hence a d18O record) pollen, plant macrofossils, chironomids, beetles and other insects, and Cladocera; (5) estimate our sampling resolution using the GRIP time scale for the isotope stratigraphies and the biostratigraphies; and (6) summarise the major patterns of compositional change in the biostratigraphies by principal component analysis or correspondence analysis. We conclude that, at the major climatic shifts at the beginning and end of the Younger Dryas, hardly any biotic lags occur (within the sampling resolution of 8--30 years) and that upland vegetation responded as fast as aquatic invertebrates. We suggest that the minor climatic changes associated with the Gerzensee and Preboreal oscillations were weakly recorded in the biostratigraphies at the lowland site, but were more distinct at higher altitudes. Individualistic responses of plant and animal species to climatic change may reflect processes in individuals (e.g. productivity and phenology), in populations (e.g. population dynamics), in spatial distributions (e.g. migrations), and in ecosystems (e.g. trophic state). We suggest that bio.