Taphonomy of pollen associated with predation

The pollen contents of owl pellets were studied in order to use them as mod ern analogues in the interpretation of fossil sediments which accumulated t hrough predation. Firstly, experiments were conducted to follow pollen thro ugh a trophic predation cycle and to observe any physical alterations. Neit her pollen in mouse droppings nor that in raptor pellets showed any clear s igns of damage as result of digestion by gastric juices, However, clear fra cturing of grass pollen grains were observed in one case. The cause of frac turing is unknown and although chewing action of rodents may be considered as one possibility, further research is necessary to study this phenomenon and its significance. Further, it was found that chemical preparation of pe llets to extract pollen resulted in the formation of high ratios of small o rganic nodules. A thin but very resistant superficial debris covering was f ound on many pellet pollen grains, but it could not be firmly established i f it is caused by digestive action in the stomachs of raptors or by the lab oratory procedure. Further, the pollen composition of pellets in the natura l setting was studied to throw light on alterations on pollen assemblages i n the predation process. The modern analogues show differences in pollen co mposition between accumulation sites and the pollen rain of the study area. They help to identify several problems of predation bias such as seasonal variations, and site locality, which should be considered in environmental interpretations of fossil material. (C) 1999 Elsevier Science B.V. All righ ts reserved.