Biodiversity and pollen analysis: modern pollen studies and the recent history of a floodplain woodland in S-W-Ireland

One of the problems with biodiversity for palynologists is that their sampl es come from an unbounded area and source area varies with both pollen/spor e type and vegetation type. There have been two broad approaches to the pro blem of: inferring diversity from pollen/spore samples; firstly the use of pollen type richness as a proxy for species richness, and secondly the 'ide ntification' of past vegetation communities aided by ecological inference a nd historical or modern data concerning species affinities and typical dive rsity. The estimation of biodiversity from pollen analysis depends upon the pollen count, taxonomic precision, source strength for individual types an d dispersal/transport of pollen from source areas to the site. A transect o f surface pollen samples is used here to test the effect of a vegetation bo undary on pollen/spore diversity and compare the pollen/spore diversity wit h the species richness of the woodland. Palynological richness (at a consta nt count sum) does, to some extent, reflect changing local vegetation along the transect. Type count curves also reflect the changes in vegetation typ e along the transect due to the partial influence of species richness on po llen/spore richness. This study suggests that depending upon the woodland c omposition, the woodland may not entirely drown-out the pollen signal of th e surrounding vegetation, and that a small woodland may be more representat ive (as a sampling site) of the valley floor diversity than a raised mire. The surface transect is also used in the interpretation of Medieval pollen levels from The Gearagh.