NON-POLLEN PALYNOMORPHS AS PROXIES OF ANTHROPOGENIC IMPACT

Spores of obligately coprophilous fungi, e.g. Sporomiella, have been shown to be a reliable proxy of grazing mammals, which has applications for studies of Neolithic agriculture. The spores of fungal pathogens, e.g. Ustilago maydis (corn smut) and Sphacelotheca reiliana (corn head smut), allowed Iroquoian (Wendat/ Huron) and Euro-Canadian settlement to be readily identified in sediments from Crawford Lake and Lake Simcoe where the pollen of Zea mays (maize/ corn) and other cultivars was rare. Other common non-pollen palynomorphs (NPP), notably algal palynomorphs, record paleolimnological conditions, but they have received little attention by geoarchaeologists. Cultural eutrophication, a common environmental response to human settlement and agriculture, is recorded by the acid-resistant remains of a wide variety of green algae (e.g., Pediastrum coenobia, Botyrococcus colonies) and dinoflagellate cysts. Desmid half-cells have been found to be particularly useful proxies of anthropogenic impact: assemblages are sensitive to variations in pH and the trophic state of lakes, and benthic taxa are quickly impacted by increased turbidity, a common result of land clearing and a by-product of eutrophication. Their recently demonstrated sensitivity to acetolysis, a common oxidizing technique routinely employed by most pollen analysts, is probably responsible for their rare mention in paleolimnological studies. Palynologists interested in geoarcheology are urged to avoid acetolysing samples in order to exploit these little-known algal palynomorphs.