DOI: 10.5061/dryad.c2fqz61m5
title: North America Holocene land cover: REVEALS-GMRF

description: As a contribution to the Past Global Changes (PAGES) LandCover6k Working
 Group, we present a new suite of land cover reconstructions with
 uncertainty for North America, based on a network of 1445 sedimentary
 pollen records and the REVEALS pollen-vegetation model coupled with a
 Bayesian spatial model. These spatially comprehensive land cover maps are
 then used to determine the pattern and magnitude of North American land
 cover changes at continental to regional scales. These Holocene
 reconstructions for North America, along with similar LandCover6k products
 now available for other continents, serve the Earth system modeling
 community by providing better-constrained land cover scenarios and
 benchmarks for model evaluation, ultimately making it possible to better
 understand the regional- to global-scale processes driving Holocene
 land-cover, carbon-cycle, and climate dynamics. Pollen-based land cover
 reconstructions were performed using the REVEALS pollen-vegetation model,
 and based on the standard protocol for PAGES LandCover6k.   We
 reconstructed land cover for 25 time intervals that cover the Holocene.
 These time intervals were defined according to the LandCover6k working
 group protocol. Time intervals are specified in kiloyears before present
 (ka), where present is defined as 1950 CE, but for time intervals
 &lt;1ka we also note the Common Era (CE) timescale. Intervals in the
 period from 11.7 to 0.7 ka have a 500-year temporal grain (11.7 to 11.2
 ka; 11.2 to 10.7 ka; etc.), while the three most recent intervals have a
 finer temporal grain (0.7-0.35 ka [1250-1600 CE]: 350 years; 0.35-0.1 ka
 [1600-1850 CE]: 250 years; 0.1-(-0.074) ka: 174 years [1850-2024 CE]) in
 order to better capture the changes associated with intensifying
 anthropogenic land use over the last five centuries. We used a grid
 resolution of 1°x1°, also as specified by the LandCover6k protocol. Within
 a grid cell, REVEALS reconstructions for multiple sites were averaged, as
 is standard practice. Taxon-level reconstructions were aggregated to three
 land cover categories: summergreen trees and shrubs (STS), evergreen trees
 and shrubs (ETS), and open vegetation/land (OVL), which includes grasses,
 herbs, and low-stature shrubs. We use the REVEALS-GMRF Bayesian
 hierarchical model to spatially interpolate the REVEALS-based
 land cover reconstructions.
description: See abstract and accompanying article. Accompanying code is found
 in: https://github.com/andydawson/reveals-na,
 https://github.com/NeotomaDB/neotoma_lakes, and
 https://github.com/BehnazP/SpatioCompo_entireHolocene_NA.
description: # North American Holocene Land Cover First unzip the file  ```
 Holocene_land_cover_trends_data.zip ``` ## REVEALS Land Cover ```
 land_grid.csv ``` Grid cell identifiers and corresponding midpoint
 latitude, longitude, and elevation (in meters) defined by the LandCover6k
 protocol. | cell\_id | x | y | elev | | :-------------- | :-------- |
 :------- | :------------------ | | cell identifier | longitude | latitude
 | elevation in meters | ``` REVEALS_LCT_gridded.csv ``` | cell\_id | x | y
 | ages | ET | OL | ST | | :-------------- | :-------- | :------- |
 :------------------- | :---------------------------------- |
 :--------------------------- | :------------------------------------ | |
 cell identifier | longitude | latitude | Years Before Present | Fraction
 Evergreen Trees and Shrubs | Fraction Open Vegetated Land | Fraction
 Summergreen Trees and Shrubs | ## REVEALS-GMRF Interpolated Land Cover The
 compendium REVEALS-GMRF Interpolated Land Cover can be downloaded
 from [https://github.com/BehnazP/SpatioCompo_entireHolocene_NA](https://github.com/BehnazP/SpatioCompo_entireHolocene_NA) These reconstructions are not contained in this Dryad submission due to a licensing conflict. Nevertheless, we describe them here,  and direct users to github. This github repository contains reconstructions of pollen-based land-cover (REVEALS) for entire Holocene (0-11700 BP). The reconstructions are based on the mathematical models developed in [https://doi.org/10.1016/j.spasta.2018.03.005](https://doi.org/10.1016/j.spasta.2018.03.005) and [https://doi.org/10.1029/2018EA000547](https://doi.org/10.1029/2018EA000547). ### Reference: * Dawson, Andria, John W. Williams, Marie-José Gaillard, Simon J. Goring, Behnaz Pirzamanbein, Johan Lindstrom, R. Scott Anderson et al. "Holocene land cover change in North America: continental trends, regional drivers, and implications for vegetation-atmosphere feedbacks." Climate of the Past Discussions 2024 (2024): 1-52. ([https://doi.org/10.5194/cp-2024-6](https://doi.org/10.5194/cp-2024-6)) * Pirzamanbein, Behnaz, Johan Lindström, Anneli Poska, and Marie-José Gaillard. "Modelling Spatial Compositional Data: Reconstructions of past land cover and uncertainties." Spatial statistics 24 (2018): 14-31. ([https://doi.org/10.1016/j.spasta.2018.03.005](https://doi.org/10.1016/j.spasta.2018.03.005)) * Pirzamanbein, Behnaz, Anneli Poska, and Johan Lindström. "Bayesian Reconstruction of Past Land Cover From Pollen Data: Model Robustness and Sensitivity to Auxiliary Variables." Earth and Space Science 7, no. 1 (2020): e2018EA00057. ([https://doi.org/10.1029/2018EA000547](https://doi.org/10.1029/2018EA000547))