Application of the Wagner's Parcimony Method in fossil plant assemblages from the Cretaceous of Europe

Abstract : Wagner's Parsimony Method, a grouping method used in phylogeny and synecology, is applied for the first time to taxon lists of fossil plant assemblages from the Albian­Cenomanian of Europe. When compared to a "classical" Correspondence Analysis, WPM allows for a higher resolution, using taxa named in "cf." or "aff." and points out both clusters and gradients. WPM results in a tree in which localities order according to their species content and minimizes the number of changes of character states (presence/absence), whereas Correspondence Analysis plots the localities along axes and maximizes the inertia ("variance" explaining most differences between localities). Close relationships exist between the plant palaeobiocenoses and palaeobiotopes, the latter being inferred from taphonomical data (especially the salinity and the clastic size). The space/time working scale can be very fine, up to the landscape ecology level.