QUATERNARY PLANT FOSSILS FROM CAVES AND ROCKSHELTERS: A DATABASE OF PALEOECOLOGICAL RECORDS FROM NEOTOMA MIDDENS IN WESTERN NORTH AMERICA

Dry caves and rock shelters in the American West host a unique and valuable paleobotanical resource – plant macrofossil remains preserved in the desiccated urine of packrats (Neotoma spp.). Ancient packrat middens are excellent sources of well-preserved plant materials that provide species-level evidence of past plant communities and records of Quaternary climate change. Middens have been studied throughout western North America from northern Mexico to southern Canada, and radiocarbon ages on midden materials range from latest Holocene to greater than 50,000 years B.P. Forty years of scientific investigations on packrat middens have resulted in thousands of identified specimens and hundreds of published reports. A newly released version of the USGS/NOAA North American Packrat Midden Database (version 3) makes this wealth of data available in a standardized, quality-controlled format, accessible online at http://esp.cr.usgs.gov/data/midden. Version 3 is an expansion of version 2, providing midden data from 163 additional source references, including 1518 additional midden samples, 1736 new radiocarbon ages, and 308 new plant macrofossil taxa. The database currently offers midden location, elevation, age, and relative abundance data for plant taxa obtained from 240 publications. In total, 2523 individual midden samples are recorded, 2834 radiocarbon ages on middens are listed, and 1500 plant taxa are searchable. Documentation is also provided that allows each unique piece of data to be traced back to its source publication(s), allowing comparison of data that have been published in multiple reports. Relative abundance data for macrofossils can be viewed in their original published format or in a standardized format wherein original data have been translated onto a standard presence-absence scale. This version of the Packrat Midden Database offers the most comprehensive, high-quality archive of midden data available for North America, and facilitates Quaternary paleoenvironmental studies on a range of local to regional scales.