Increase in soil organic carbon by agricultural intensification in northern China

Acknowledgements. This research was supported by National Natural Science Foundation of China (no. 31370527 and 31261140367) and the National Science and Technology Support Program of China (no. 2012BAD14B01-2). The authors gratefully thank the Huantai Agricultural Station for providing of the Soil Fertility Survey data. We also thank Zheng Liang from China Agricultural University for the soil sampling and analysis in 2011. Thanks are extended to Jessica Bellarby for helpful discussion and suggestions.

Assessment of land use and land cover changes during the last 50 years in oases and surrounding rangelands of Xinjiang, NW China

An analysis of historical Corona images, Landsat images, recent radar and Google Earth® images was conducted to determine land use and land cover changes of oases settlements and surrounding rangelands at the fringe of the Altay Mountains from 1964 to 2008. For the Landsat datasets supervised classification methods were used to test the suitability of the Maximum Likelihood Classifier with subsequent smoothing and the Sequential Maximum A Posteriori Classifier (SMAPC). The results show a trend typical for the steppe and desert regions of northern China. From 1964 to 2008 farmland strongly increased (+ 61%), while the area of grassland and forest in the floodplains decreased (- 43%). The urban areas increased threefold and 400 ha of former agricultural land were abandoned. Farmland apparently affected by soil salinity decreased in size from 1990 (1180 ha) to 2008 (630 ha). The vegetated areas of the surrounding rangelands decreased, mainly as a result of overgrazing and drought events.The SMAPC with subsequent post processing revealed the highest classification accuracy. However, the specific landscape characteristics of mountain oasis systems required labour intensive post processing. Further research is needed to test the use of ancillary information for an automated classification of the examined landscape features.

Palaeovegetation in China during the late Quaternary: Biome reconstructions based on a global scheme of plant functional types

Two previous reconstructions of palaeovegetation across the whole of China were performed using a simple classification of plant functional types (PFTs). Now a more explicit, global PFT classification scheme has been developed, and a substantial number of additional pollen records have become available. Here we apply the global scheme of PFTs to a comprehensive set of pollen records available from China to test the applicability of the global scheme of PFTs in China, and to obtain a well-founded reconstruction of changing palaeovegetation patterns. A total of 806 pollen surface samples, 188 mid-Holocene (MH, 6000 14C yr BP) and 50 last glacial maximum (LGM, 18,000 14C yr BP) pollen records were used to reconstruct vegetation patterns in China, based on a new global classification system of PFTs and a standard numerical technique for biome assignment (biomization). The biome reconstruction based on pollen surface samples showed convincing agreement with present potential natural vegetation. Coherent patterns of change in biome distribution between MH, LGM and present are observed. In the MH, cold and cool-temperate evergreen needleleaf forests and mixed forests, temperate deciduous broadleaf forest, and warm-temperate evergreen broadleaf and mixed forest in eastern China were shifted northward by 200–500 km. Cold-deciduous forest in northeastern China was replaced by cold evergreen needleleaf forest while in central northern China, cold-deciduous forest was present at some sites now occupied by temperate grassland and desert. The forest–grassland boundary was 200–300 km west of its present position. Temperate xerophytic shrubland, temperate grassland and desert covered a large area on the Tibetan Plateau, but the area of tundra was reduced. Treeline was 300–500 m higher than present in Tibet. These changes imply generally warmer winters, longer growing seasons and more precipitation during the MH. Westward shifts of the forest–shrubland–grassland and grassland–desert boundaries imply greater moisture availability in the MH, consistent with a stronger summer monsoon. During the LGM, in contrast, cold-deciduous forest, cool-temperate evergreen needleleaf forest, cool mixed forests, warm-temperate evergreen broadleaf and mixed forest in eastern China were displaced to the south by 300–1000 km, while temperate deciduous broadleaf forest, pure warm-temperate evergreen forest, tropical semi-evergreen and evergreen broadleaf forests were restricted or absent from the mainland of southern China, implying colder winters than present. Strong shifts of temperate xerophytic shrubland, temperate grassland and desert to the south and east in northern and western China and on the Tibetan Plateau imply drier conditions than present.

An evaluation of the simulated water balance of Eurasia and northern Africa at 6000 yr B.P. using lake status data

Changes in the water balance of Eurasia and northern Africa in response to insolation forcing at 6000 y BP simulated by five atmospheric general circulation models have been compared with observations of changes in lake status. All of the simulations show enhancement of the Asian summer monsoon and of the high pressure cells over the Pacific and Central Asia and the Middle East, causing wetter conditions in northern India and southern China and drier conditions along the Chinese coast and west of the monsoon core. All of the models show enhancement of the African monsoon, causing wetter conditions in the zone between ca 10–20 °N. Four of the models show conditions wetter than present in southern Europe and drier than present in northern Europe. Three of the models show conditions similar to present in the mid-latitude continental interior, while the remaining models show conditions somewhat drier than present. The extent and location of each of the simulated changes varies between the models, as does the mechanism producing these changes. The lake data confirm some features of the simulations, but indicate discrepancies between observed and simulated climates. For example, the data show: (1) conditions wetter than present in central Asia, from India to northern China and Mongolia, indicating that the simulated Asian monsoon expansion is too small; (2) conditions wetter than present between ca. 10–30 °N in Africa, indicating that the simulated African monsoon expansion is too small; (3) that northern Europe was drier, but the area of significantly drier conditions was more localized (around the Baltic) than shown in the simulations; (4) that southern Europe was wetter than present, apparently consistent with the simulations, but pollen data suggest that this reflects an increase in summer rainfall whereas the models show winter precipitation, and (5) that the mid-latitude continental interior was generally wetter than present.

Taphonomy of Bouchardia rosea (Rhynchonelliformea, Brachiopoda) shells from Ubatuba Bay, Brazil: implications for the use of taphonomic signatures in (paleo)environmental analysis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)