PARENT SESSION
Poster Session #22: Paleoecology.
Wednesday, August 8, 2001. Presentation from 10:30 AM to 12:00 PM. Exhibition Hall
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Comparisons of modern woodrat (Neotoma cinerea) midden assemblages with surrounding vegetation.
Lyford, Mark1, Jackson, Stephen1, Gray, Steve1, Gerow, Ken1, Eddy, Rob1, 1
ABSTRACT- Although thousands of fossil woodrat (Neotoma spp.) middens have been collected and analyzed from the western United States to reconstruct vegetation and climate histories, very few modern comparisons of woodrat middens and surrounding plant communities have been conducted. We studied 59 modern Neotoma cinerea middens from 5 sites in northern Utah, Wyoming and southern Montana to assess the flora- and vegetation-sampling properties of plant macrofossil assemblages from middens. Vegetation surveys within 50 m of each collection site included presence, relative abundance (scale of 1-5), and percent cover measures for 29 species. Our results indicate that macrofossils of certain species (e.g., Juniperus osteosperma, Pinus edulis, Opuntia polyacantha) consistently occur in middens regardless of abundance in the surrounding vegetation, while others (e.g., Bromus tectorum) are poorly represented, even when locally abundant. The relative abundance of plant fragments in middens for some taxa are not always representative of their abundance on the landscape. For example, Juniperus osteosperma tends to be over-represented while Artemisia tridentata is under-represented. In addition, species not occurring in the near vicinity were occasionally observed in middens, indicating long-distance transport of plant remains. Our data demonstrate that many species are consistently recorded in midden assemblages when present in surrounding vegetation, therefore confirming that middens can be used as reliable records of presence/absence of these species.
KEY WORDS: woodrat, midden, midden-vegetation relationship