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The water and sediment supply to the lower reach and estuary of the Yellow (Huanghe) River have been altered to a very significant degree by the construction of numerous small to large reservoirs and the progressive implementation of water and soil conservation measures across the entire drainage basin since the late 1950s, followed by a basin-scale water regulation program since 2002. There is an urgent need to know how progradation of the Yellow River delta (YRD), an area on which people live and farm, has continued and will continue to respond to these controls. This study examines the changing patterns of water and sediment supply to the YRD over the period of 1950-2013 and, using remote sensing, it evaluates the morphological changes of the delta during 1976-2013. Although both water and sediment input to the delta have been described as declining significantly since the mid 1960s, we show that since 2005 the supply of water has remained at around 20 billion m 3 yr −1 and that for sediment at about 0.13 billion t yr −1 ; water input has been even slightly increasing. The dynamics of extension/shrinking and avulsion in river-mouth channels and accretion/erosion of shorelines is an integrated response to the complex variations in both sediment and water supply. This study develops a quantitative relationship between water and sediment supply and the area of land accretion and it predicts the critical condition for land accretion in the YRD. To ensure that delta land will not be lost, care is needed in the future implementation of the basin-scale water regulation program.

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An improved procedure for preciee meaeurement of chlorine isotope ratioe in geological eamplee baeed on CerC1+ ion by thermal ioniration maee epectrometry ie reported. Uaing thie procedure the a'Cl/aaCl ratio of N18T SRM 976 ie determined to be 0.318929f0.000028(1~) 1296 XIAO, ZHOU, AND LIU with a precieion of 0.009%(1a). The procedure hae been eucceeefully applied t o etudy t h e variation of chlorine ieotopic aompoeitione in seawater and t o determine atomic weight of chlorine.

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The effects of biological soil crusts (BSC) on vascular plant growth can be positive, neutral or negative, and little information is available on the impacts of different BSC successional stages on vascular plant population dynamics.• We analysed seedling emergence, survival, plant growth and reproduction in response to different BSC successional stages (i.e. habitats: bare soil, cyanobacteria, lichen and moss crusts) in natural populations of Echinops gmelinii Turcz. in the Tengger Desert of northwest China. The winter annual E. gmelinii is a dominant pioneer herb after sand stabilisation.• During the early stages of BSC succession, the studied populations of E. gmelinii were characterised by high density, plant growth and fecundity. As the BSC succession proceeded beyond moss crusts, the fecundity decreased sharply, which limited seedling recruitment. Differences in seedling survival among the successional stages were not evident, indicating that BSC have little effect on survival in arid desert regions. Moreover, E. gmelinii biomass allocation exhibited low plasticity, and only reproductive allocation was sensitive to the various habitats. Our results further suggest that the negative effects of BSC succession on population dynamics are primarily driven by increasing topsoil water-holding capacity and decreasing rain water infiltration into deeper soil.• We conclude that BSC succession drives population dynamics of E. gmelinii, primarily via its effect on soil moisture. The primary cause for E. gmelinii population decline during the moss-dominated stage of BSC succession is decreased fecundity of individual plants, with declining seed mass possibly reducing the success of seedling establishment.