BEETLE DIVERSITY AND HISTORICAL ECOLOGY OF WOODLANDS IN FLANDERS

Extensive data on the present-day carab id beetle tau na occurring in woods of FI anders were compared with a unique data-set ofarchaeological carabid remains from a Late and Post-Roman forest at Velzeke (Eastern Flanders), within the framework of a study on the hi sto ri ca l ecology of wood lands in Flanders. Integration of these data on 14 woods revealed that most have been significantly impoverished w ith respect to their stenotopic wood land beetle fa una. The carabid species' diversity is higher in severa! small and relatively recent wood lands compared to that in larger ancient forests, regardless of whether this di versity is evaluated by rarefaction or by mean spec ies richness per standardi sed year sample data . This pattern is primarily caused by the presence, in forest J'ragments, of many species from su rrounding open habitats . Typica l wood land beetl es show a recluced di spersal power (constant brachypte ry) and appea r to be strongly linked to larger anc ient woods. Knowledge o fhi storica l ecological factors , other than actua l s ize oftbe fo rests , further a ids the expianat ion of the observed ground beetle assemblages in the specifie forests or sites. Pre liminary results of population genetics, fo r the eury top ic forest carab id beetle Abax a/er, showed signif"icant genetic differentiation between popul ations (due to red uced gene flo w) at a re latively large spatial sca le, a lthough genetic eros ion cannot (yet ?) be observed fo r this species. Key words· : woodland, biodivers ity, historical ecology, deforestation events, woodland area, wood exp lo itation, archaeo logy, habitat fragmentation, ground beetles (Cacabidae), anc ient wood land indi cators, dispersal power, population geneti cs, A bax a ter, reg ion o f Flanders