USGS North American Packrat Midden Database Completed
USGS North American Packrat Midden Database, Version 5.0
A Database of Paleoecological Records from Neotoma Middens in Western North America
Dry caves and rockshelters in western North American host a unique and valuable paleobotanical resource known as packrat middens. Packrat (Neotoma spp.) middens composed of desiccated fecal matter and urine also contain well preserved fossil plant materials.
Over fifty years of scientific investigations on packrat middens have produced thousands of identified plant specimens and hundreds of published reports. The USGS North American Packrat Midden Database (version 5.0) makes this wealth of data available in a standardized, quality-controlled format. 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.
What are packrat middens and what do they tell us about past environments?
Middens are waste piles that packrats construct out of fecal matter and urine (Figure 1). Packrats incorporate pieces of plant material, bone, and other items which they habitually collect from their environment into their middens. The packrat's sticky, viscous urine acts like a cement which binds the midden material together into a solid mass.
Middens constructed in dry caves and rockshelters where they are protected from moisture may be preserved for tens-of-thousands of years (Figure 2). Fossil plant remains recovered from ancient midden deposits are often perfectly preserved, can be identified to species-level, and provide excellent material for radiocarbon dating. Radiocarbon-dated fossil midden assemblages provide detailed inventories of the plants and animals that lived in the vicinity of the collection site during past time periods. A series of dated middens from neighboring sites can provide a long-term record of changing plant communities and climate for a local area.
USGS North American Packrat Midden Database
This version of the Midden Database contains data for 3,331 packrat midden samples (Figure 3.) obtained from published sources as well as unpublished data contributed by researchers. Compared to the previous version of the Midden Database (i.e., ver. 4), this version of the database (ver. 5.0) has been expanded to include more precise midden-sample site location data, calibrated midden-sample age data (Figure 4.), and plant functional type (PFT) assignments for the taxa in each midden sample. In addition, World Wildlife Fund ecoregion and major habitat type (MHT) assignments and modern climate and bioclimate data are provided for each midden-sample site location.
Methods of Quality Control and Data Standardization
This dataset aims to preserve original data as it was published by each midden analyst, therefore the quality of the data is only as good as the original published data. The use and comparison of midden data produced by multiple sources is complicated by the fact that midden analysts use many different methods to record the relative abundance of plant macrofossil taxa in middens. This dataset preserves original relative abundance data as published; however this dataset also translates all original data into a standardized presence-absence scale (2=present and common, 1=present but rare [and thus could be a contaminant of a different age], 0=absent) according to the relative abundance scheme(s) used and defined by each midden analyst.
Previous Database Versions:
Strickland, L. E., Schumann, R. R., Thompson, R. S., Anderson, K. H. & Pelltier, R. T., 2016. USGS/NOAA North American Packrat Midden Database, Version 4 (No longer available online).
Strickland, L. E., Schumann, R. R., Thompson, R. S., Anderson, K. H. & Pelltier, R. T., 2006. USGS/NOAA North American Packrat Midden Database, Version 3 (No longer available online).
Strickland, L. E., Schumann, R. R., Thompson, R. S. & Anderson, K. H., 2002. USGS/NOAA North American Packrat Midden Database, Version 2 (No longer available online).
Schumann, R. R., Thompson, R. S. & Anderson, K. H., 1998. USGS/NOAA North American Packrat Midden Database, Version 1 (No longer available online).
A Database of Paleoecological Records from Neotoma Middens in Western North America
Dry caves and rockshelters in western North American host a unique and valuable paleobotanical resource known as packrat middens. Packrat (Neotoma spp.) middens composed of desiccated fecal matter and urine also contain well preserved fossil plant materials.
Over fifty years of scientific investigations on packrat middens have produced thousands of identified plant specimens and hundreds of published reports. The USGS North American Packrat Midden Database (version 5.0) makes this wealth of data available in a standardized, quality-controlled format. 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.
What are packrat middens and what do they tell us about past environments?
Middens are waste piles that packrats construct out of fecal matter and urine (Figure 1). Packrats incorporate pieces of plant material, bone, and other items which they habitually collect from their environment into their middens. The packrat's sticky, viscous urine acts like a cement which binds the midden material together into a solid mass.
Middens constructed in dry caves and rockshelters where they are protected from moisture may be preserved for tens-of-thousands of years (Figure 2). Fossil plant remains recovered from ancient midden deposits are often perfectly preserved, can be identified to species-level, and provide excellent material for radiocarbon dating. Radiocarbon-dated fossil midden assemblages provide detailed inventories of the plants and animals that lived in the vicinity of the collection site during past time periods. A series of dated middens from neighboring sites can provide a long-term record of changing plant communities and climate for a local area.
USGS North American Packrat Midden Database
This version of the Midden Database contains data for 3,331 packrat midden samples (Figure 3.) obtained from published sources as well as unpublished data contributed by researchers. Compared to the previous version of the Midden Database (i.e., ver. 4), this version of the database (ver. 5.0) has been expanded to include more precise midden-sample site location data, calibrated midden-sample age data (Figure 4.), and plant functional type (PFT) assignments for the taxa in each midden sample. In addition, World Wildlife Fund ecoregion and major habitat type (MHT) assignments and modern climate and bioclimate data are provided for each midden-sample site location.
Methods of Quality Control and Data Standardization
This dataset aims to preserve original data as it was published by each midden analyst, therefore the quality of the data is only as good as the original published data. The use and comparison of midden data produced by multiple sources is complicated by the fact that midden analysts use many different methods to record the relative abundance of plant macrofossil taxa in middens. This dataset preserves original relative abundance data as published; however this dataset also translates all original data into a standardized presence-absence scale (2=present and common, 1=present but rare [and thus could be a contaminant of a different age], 0=absent) according to the relative abundance scheme(s) used and defined by each midden analyst.
Previous Database Versions:
Strickland, L. E., Schumann, R. R., Thompson, R. S., Anderson, K. H. & Pelltier, R. T., 2016. USGS/NOAA North American Packrat Midden Database, Version 4 (No longer available online).
Strickland, L. E., Schumann, R. R., Thompson, R. S., Anderson, K. H. & Pelltier, R. T., 2006. USGS/NOAA North American Packrat Midden Database, Version 3 (No longer available online).
Strickland, L. E., Schumann, R. R., Thompson, R. S. & Anderson, K. H., 2002. USGS/NOAA North American Packrat Midden Database, Version 2 (No longer available online).
Schumann, R. R., Thompson, R. S. & Anderson, K. H., 1998. USGS/NOAA North American Packrat Midden Database, Version 1 (No longer available online).