LegacyVegetation: North American reconstruction of past plant cover and total tree cover from pollen archives of the last 14 ka@en

This data set presents the reconstructed vegetation cover for 1040 North American sites based on harmonized pollen data from the data set LegacyPollen 2.0. Sugita's REVEALS model (2007) was applied to all pollen records using REVEALSinR from the DISQOVER package (Theuerkauf et al. 2016). Pollen counts were translated into vegetation cover by accounting for taxon-specific pollen productivity and fall speed. Additionally, relevant source areas of pollen were calculated using the aforementioned taxon-specific parameters and a Gaussian plume model for deposition and dispersal. Values for relative pollen productivity and fall speed from the synthesis from Wiezcorek and Herzschuh (2010) were updated with recent studies used to reconstruct vegetation cover. The average values from all Northern Hemisphere values were used where taxon-specific continental values were unavailable. As REVEALS was conceived to reconstruct vegetation from large lakes, only records originating from large lakes (>= 50h) are marked as \"valid as site\" in the dataset. Reconstructions from other records can be used when spatially averaging several together. An example script to do so is provided on Zenodo (https://doi.org/10.5281/zenodo.12800290). Reconstructed tree cover was validated using modern Landsat remote sensing forest cover. Reconstructed tree cover has much lower errors than the original arboreal pollen percentages. Reconstructions of individual taxa are more uncertain. We present tables with reconstructed vegetation cover for all continents with original parameters. As further details, we list a table with the taxon-specific parameters used, metadata for all records, and a list of parameters adjusted in the default version of REVEALSinR.本数据集基于LegacyPollen 2.0数据集的标准化孢粉数据，重建了北美1040处遗址的植被覆盖度。研究采用DISQOVER软件包（托伊尔克夫等，Theuerkauf et al., 2016）中的REVEALSinR工具，对所有孢粉记录应用萨吉塔（Sugita）于2007年提出的REVEALS模型。通过考虑类群特异性的孢粉生产力与沉降速率，将孢粉计数转换为植被覆盖度。此外，研究借助上述类群特异性参数与用于孢粉沉积与扩散的高斯烟羽模型，计算得到孢粉的有效源区。本研究采用最新研究成果，对维兹科雷克与赫尔茨舒（Wiezcorek & Herzschuh, 2010）综合得到的相对孢粉生产力与沉降速率参数进行了更新，以用于植被覆盖度重建。当无法获取类群特异性的区域数值时，本研究采用北半球的平均数值替代。由于REVEALS模型最初是针对大型湖泊的植被重建而设计，因此本数据集仅将源自大型湖泊（面积≥50公顷）的记录标记为"valid as site"。若对多条记录开展空间平均处理，则可使用其他类型记录的重建结果。相关操作示例脚本已上传至Zenodo平台（https://doi.org/10.5281/zenodo.12800290）。重建得到的乔木覆盖度已通过现代Landsat遥感森林覆盖数据进行了验证。重建得到的乔木覆盖度的误差远低于原始乔木孢粉百分比数据。单类群的重建结果不确定性更高。本研究附带了基于原始参数得到的全球各洲植被覆盖度重建结果表格。补充细节方面，本研究还列出了所用类群特异性参数表、所有记录的元数据，以及REVEALSinR默认版本中调整后的参数列表。