Cover and density data of southwestern ponderosa pine understory plants in permanent chart quadrats (2002-2020+): 2nd edition

This data publication includes cover and density data collected on 101 permanent 1 meter (m) x 1 m (1-m²) quadrats located within southwestern ponderosa pine ecosystems near Flagstaff, Arizona, USA. Individual plants in these quadrats were identified and mapped annually for 23 years (2002-2024). The original chart quadrats were established between 1912 and 1927. We provide the following data and data formats: (1) digitized maps of all plant locations in shapefile and geodatabase format, (2) shapefiles showing annual locations of each individual plant species, (3) exported annual maps of each quadrat in TIFF and PDF format, (4) annual basal area of each species per quadrat for species mapped as polygons, (5) tabular representation of polygon areas and centroid locations for plant species mapped as polygons, (6) tabular representation of point locations for plant species mapped as points, (7) plot-scale 20 m x 20 m overstory tree canopy cover, tree basal area, parent material, and elevation, (8) quadrat-scale information (e.g., quadrat site and number, coordinates in UTM Zone 12 and latitude/longitude, and descriptive comments for each quadrat), (9) plant species list, (10) summary of plant species observed in each quadrat, (11) summary of quadrats mapped by site and year, and (12) data formatted for use in Integral Projection Models (IPM) and plant population analyses.
The original chart quadrats were established to determine the effects of domestic livestock grazing on herbaceous plants and pine seedlings. Today these data provide opportunities to examine the effects of climate and land-use change on plant demography, population dynamics, and community processes.
For more information about this study and these data see Moore et al. (2022, https://doi.org/10.1002/ecy.3661). All associated novel code files are permanently archived in a Zenodo repository (https://doi.org/10.5281/zenodo.7581945). The first edition of these data, Moore et al. (2021; https://doi.org/10.2737/RDS-2021-0092) contains data from 2020-2022. This second edition, published on 04/16/2025, includes data for 2023 and 2024. Modifications were made to the individual species shapefile folder names, and additional data-entry errors were found and fixed. Specifically we added “2002-2024” to all the individual species folder names to indicate that the folder contained all data between those years. On Plot 26346 we fixed an error in which the quadrat was incorrectly rotated in 2022. On Plot 30737 we fixed an error in which the quadrat was incorrectly rotated in the years 2009-2015. We found that Thinopyrum intermeidium had been historically misidentified as Pascopyrum smithii on Quadrats 3 and 30740, and that Thinopyrum intermeidium had been historically misidentified as Elymus trachycaulus on Quadrats 3, 4, 30739 and 30740. All cases were corrected to Thinopyrum intermeidium.