Model-based quantitative reconstruction of past plant cover in Europe has shown great potential for: (i) testing hypotheses related to Holocene vegetation dynamics, biodiversity, and their relationships with climate and land use; (ii) studying long term interactions between climate and land use. Similar model-based quantitative reconstruction of plant cover in China has been restricted due to the lack of standardized datasets of existing estimates of relative pollen productivity (RPP). This study presents the first synthesis of all RPP values available to date for 39 major plant taxa from temperate China and proposes standardized RPP datasets that can be used for model-based quantitative reconstructions of past plant cover using fossil pollen records for the region. We review 11 RPP studies in temperate China based on modern pollen and related vegetation data around the pollen samples. The study areas include meadow, steppe and desert vegetation, various woodland types, and cultural landscapes. We evaluate the strategies of each study in terms of selection of study areas and distribution of study sites; pollen- and vegetation-data collection in field; vegetation-data collection from satellite images and vegetation maps; and data analysis. We compare all available RPP estimates, select values based on precise rules and calculate mean RPP estimates. We propose two standardized RPP datasets for 31 (Alt1) and 29 (Alt2) plant taxa. The ranking of mean RPPs (Alt-2) relative to Poaceae (= 1) for eight major taxa is: Artemisia (21) > Pinus (18.4) > Betula (12.5) > Castanea (11.5) > Elaeagnaceae (8.8) > Juglans (7.5) > Compositae (4.5) > Amaranthaceae/Chenopodiaceae (4). We conclude that although RPPs are comparable between Europe and China for some genera and families, they can differ very significantly, e.g., Artemisia, Compositae, and Amaranthaceae/Chenopodiaceae. For some taxa, we present the first RPP estimates e.g. Castanea, Elaeagnaceae, and Juglans. The proposed standardized RPP datasets are essential for model-based reconstructions of past plant cover using fossil pollen records from temperate China.

The Zoige Basin on the eastern Tibetan Plateau has the largest area of highland peatlands in China. However, the development history of these peatlands is still poorly understood. Understanding how these carbon-rich ecosystems responded to change in the Asian summer monsoons during the Holocene will provide insight into the peatland carbon accumulation processes under different climate boundary conditions. Here, we document the timing of initiation and expansion histories of these peatlands using 59 new basal peat ages across the Zoige Basin, with 29 ages for initiation analysis and 30 additional ages for lateral expansion analysis. Also, we synthesized basal ages from 26 sites and carbon accumulation records at four sites from previous studies in this region. The results show that the peatland initiation is widespread at 11.5-10 and 7-6 kyr (1 kyr = 1000 cal. yr BP) and the minimum initiation periods occurred after 5 kyr. Our multiple basal ages along eight transects show that slopes are a dominant control on peatland lateral expansion rates, with very slow and less variable rates at slopes >0.4°. Furthermore, we found a significant relationship between peatland basal ages and peat depths from 85 sites, suggesting relatively uniform peat properties. Carbon accumulation rates from detailed downcore analysis at four sites and on the basis of peat depth-basal age relationship show similar patterns with a peak carbon accumulation at 10-8 kyr. On the basis of estimated mean values of bulk density and carbon content from the region, the Holocene average C accumulation for the Zoige Basin is 31.1 g C/m 2 /yr. The widespread peatland initiation and rapid accumulation in the early Holocene were likely in response to higher temperature and stronger summer monsoon intensity, while the slowdown of peatland development during the late Holocene might have been caused by climate cooling and drying.

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Quantifying the relationship between pollen and vegetation is an essential step in the pollen-based quantitative reconstruction of past vegetation cover. In this study, we use the Extended R-Value (ERV) model and a modern dataset of pollen (collected from moss polsters) and related vegetation from 50 sites in the Daba Mountains (subtropical China) to (i) estimate the relevant source area of pollen (RSAP) of the moss samples and the relative pollen productivities (RPPs) of nine major plant taxa-characteristic of the region, and (ii) evaluate the obtained RPPs. The RSAP estimates of moss polsters vary between 225 and 610 m depending on the ERV submodels and models of pollen dispersal and deposition used. The RPP estimates are different from values published in previous studies from temperate and subtropical China. This may be explained by differences in methodology, climate and vegetation (species composition and spatial distribution), of which vegetation is probably the most important factor. The ranking of the RPP estimates for the nine taxa is Pinus > Juglandaceae > D − Quercus (deciduous Quercus) > Poaceae > Rosaceae > Cyperaceae > Anacardiaceae > Castanea > Fabaceae. We use a 'leave-one-out' cross-validation strategy and the Landscape Reconstruction Algorithm (LRA) for pollen-based reconstruction of regional and local plant cover to evaluate the ERV model-based RPP estimates. Both the REVEALS (Regional Estimates of VEgetation Abundance from Large Sites)-based and the LOVE (LOcal Vegetation Estimates)-based plant cover using the RPP estimates are closer to the modern vegetation composition than pollen percentages, thus confirming the applicability of the ERV model and the LRA approach in subtropical China.Abbreviations. D LRA-obs , Euclidian distance between the LRAreconstructed and the observed local vegetation composition; D pol-obs , Euclidian distance between the pollen proportions and the observed local vegetation composition; D-Quercus, deciduous

Using unsupervised classification, visual interpretation, slope mask with the aid of ArcGIS and ERDAS, we analyzed the peatland area change in the Zoige Basin, eastern Tibetan Plateau, during last two decades on the basis of 12 Landsat-TM images. The results showed that the peatland area decreased seriously from 4143.39 to 3407.29 km 2 between early 1990s and 2000 and increased slightly to 3588.71 km 2 in 2009. Though peatland area change is positively correlated with the climate trend, the correlation is not very significant. Instead, in considering the population increase, stock development and government policy, we suggest that human activity is likely the more important factor that caus the peatland area variations.

Abstract. We present the first gridded and temporally continuous quantitative pollen-based plant-cover reconstruction for temperate and northern subtropical China over the Holocene (11.7 ka to present) obtained by applying the Regional Estimates of VEgetation Abundance from Large Sites (REVEALS) model. The objective is to provide a dataset of pollen-based land cover for the last ca. 12 millennia that is suitable for palaeoclimate modelling and for the evaluation of simulated past vegetation cover from dynamic vegetation models and anthropogenic land-cover change (ALCC) scenarios. The REVEALS reconstruction was achieved using 94 selected pollen records from lakes and bogs at a 1∘ × 1∘ spatial scale and a temporal resolution of 500 years between 11.7 and 0.7 ka and in three recent time windows (0.7–0.35 ka, 0.35–0.1 ka, and 0.1 ka to present). The dataset includes REVEALS estimates of cover and their standard errors (SEs) for 27 plant taxa in 75 1∘ × 1∘ grid cells distributed within the study region. The 27 plant taxa were also grouped into 6 plant functional types and 3 land-cover types (coniferous trees CT, broadleaved trees BT, and C3 herbs/open land (C3H/OL)), and their REVEALS estimates of cover and related SEs were calculated. We describe the protocol used for the selection of pollen records and the REVEALS application (with parameter settings) and explain the major rationales behind the protocol. As an illustration, we present, for eight selected time windows, gridded maps of the pollen-based REVEALS estimates of cover for the three land-cover types (CT, BT, and C3H/OL). We then discuss the reliability and limitations of the Chinese dataset of Holocene gridded REVEALS plant cover, and its current and potential uses. The dataset is available at the National Tibetan Plateau Data Center (TPDC; Li, 2022; https://doi.org/10.11888/Paleoenv.tpdc.272292).

Abstract. We present the first gridded and temporally continuous quantitative pollen-based plant-cover reconstruction for temperate and northern sub-tropical China over the Holocene (11.7 ka BP to present) using the Regional Estimates of Vegetation Abundance from Large Sites (REVEALS) model. The objective is to provide a dataset of pollen-based land cover for the last ca. twelve millennia suitable for palaeoclimate modeling and evaluation of simulated past vegetation cover from dynamic vegetation models and anthropogenic land-cover change (ALCC) scenarios. The REVEALS reconstruction was achieved using 94 selected pollen records from lakes and bogs at a 1°×1° spatial scale and a temporal resolution of 500 years between 11.7 and 0.7 ka BP, and three recent time windows (0.7–0.35 ka BP, 0.35–0.1 ka BP, and 0.1 ka BP–present). The dataset includes REVEALS estimates of cover and their standard errors (SEs) for 27 plant taxa in 75 1°×1° grid cells distributed within the study region. The 27 plant taxa were also grouped into six plant functional types and three land-cover types (coniferous trees CT, broadleaved trees BT, and C3 herbs C3H/open land OL), and their REVEALS estimates of cover and related SEs were calculated. We describe the protocol used for the selection of pollen records and the REVEALS application (with parameter setting), and explain the major rationales behind the protocol. As an illustration we present, for eight selected time windows, gridded maps of the pollen-based REVEALS estimates of cover for the three land-cover types (CT, BT, and C3H/OL). We then discuss the reliability and limitations of the Chinese dataset of Holocene gridded REVEALS plant-cover, and its current and potential uses. The dataset is available at the National Tibetan Plateau Data Center (TPDC; https://data.tpdc.ac.cn/en/disallow/d18d2b7e-25fe-49da-b1bd-2be6014162b0/).

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