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Many coastal sand dune systems in the UK and other parts of the world have experienced a decline in bare sand extent and dune mobility over the past 70 years, accompanied by increased coverage of coarse grass, scrub and woodland vegetation. This has raised concerns amongst nature conservationists about the survival of dune specialist species. Opinions are divided, however, regarding what management interventions should be made to counteract these trends. This paper reviews the factors which have contributed to progressive dune system stabilization at Sandscale Haws, located on the Irish Sea coast in Northwest England, considers the implications for the site of UKCP18 future climate change projections, and discusses the options and plans for future adaptive management. Analaysis of aerial photographs indicated a large reduction in bare sand area between 1946 and 1988 (from >34% to 9% of the dune system), since when there has been a further decline to 1.7%. Consideration of the evidence suggests that a trend towards a warmer, slightly wetter and less windy climate has been the main driver of stabilization, although atmospheric nitrogen deposition, increasing atmospheric CO2 concentrations, reduced grazing intensity, reduced human disturbance from the mid-1980s onwards and a tendency for shoreline progradation on the west-facing coast have played contributing roles. Some species characteristic of open habitats can still be found in good numbers in parts of the dune system, but without increased management it is likely they will decline further and some may become locally extinct. Since the site is of national and international importance for a number of nationally scarce plant and animal species it is considered that there is both a legal and an ethical duty to attempt to maintain suitable habitat for their survival. As a National Nature Reserve Sandscale Haws provides a suitable 'natural laboratory' within which to research the effectiveness of different intervention methods. A number of small-scale dune rejuvenation methods have been trialled since 2015, and options for larger scale interventions, including turf stripping and possible dune notching, are currently being evaluated as part of the nation-wide Dynamic Dunescapes project. [ABSTRACT FROM AUTHOR]

Producing food, transportation, and energy for seven billion people has led to large and widespread increases in the use of synthetic nitrogen (N) fertilizers and fossil fuel combustion, resulting in a leakage of N into the environment as various forms of air and water pollution. The global N cycle is more severely altered by human activity than the global carbon (C) cycle, and reactive N dynamics affect all aspects of climate change considerations, including mitigation, adaptation, and impacts. In this special issue of Biogeochemistry, we present a review of the climate-nitrogen interactions based on a technical report for the United States National Climate Assessment presented as individual papers for terrestrial and aquatic ecosystems, agriculture and human health within the US. We provide a brief overview of each of the paper's main points and conclusions is presented in this foreword summary. [ABSTRACT FROM AUTHOR]

[Display omitted] • Grassland degradation is the main reason for the decline in carbon storage. • The carbon storage of farmland has increased significantly. • The risk of carbon storage reduction in the future is still high. The carbon storage of terrestrial ecosystems is closely related to global climate change. Therefore, assessing the impact of land-use changes on carbon storage is instructive to reduce global carbon emissions. Taking an arid region in northwest China as an example, this paper analyzed the land-use changes in arid region from 1980 to 2015. It used the CA-Markov model to predict the land-use pattern from 2020 to 2050, the carbon storage and sequestration module in Integrated Valuation of Ecosystem Services and Tradeoffs (Invest) mode to assess and predict ecosystem carbon storage over the past 35 years and in the next 30 years and discusses the impact of land-use changes on the carbon storage of terrestrial ecosystems. The results showed that: (1) The high-value areas of carbon storage in arid region were primarily concentrated in grassland, forests and farmland, and the low-value areas of carbon storage were mainly in desert areas. (2) The carbon storage in arid region showed a downward trend. From 1980 to 2015, the carbon reserves of terrestrial ecosystems in arid region decreased by 90.95 Tg, and the net loss of carbon reserves from 2020 to 2050 was 14.72 Tg. Grassland degradation was the main reason for the reduction of carbon storage in arid region. (3) The carbon storage of farmland had increased significantly, but the expansion of farmland dominated by high carbon density grassland, wetland and forest, had reduced the overall carbon storage of the arid region. [ABSTRACT FROM AUTHOR]

Much of our existing knowledge of Middle Jurassic paleoclimate is based on well-dated marine isotopic records that show fluctuations between warm (greenhouse effected) and cool climates. In contrast, much less is known from contemporaneous terrestrial deposits that are often difficult to correlate stratigraphically with marine successions, and are typically considered as showing regional rather than global signals. In this paper we show that the carbon-isotopic, petrological and floral record through 20 m thick coals in the Northern Qaidam Basin (NW, China) represents a relatively comprehensive northern hemisphere Bajocian (Middle Jurassic) record for terrestrial climatic change. δ13C coal values for 88 samples from the Yuqia area in Northern Qaidam Basin range from–25.3‰ to –22.5‰, indicating that C3 plants were the main coal-forming vegetation in the region during the Middle Jurassic. This isotopic variation follows fluctuations in the composition of ferns and gymnosperms, where higher ratios correspond to more negative δ13C values. The similar carbon isotope values of gymnosperms and coal from the Yuqia area indicate that the coal comprises a high proportion of organic material derived from gymnosperm taxa, which is consistent with the very high abundance of diterpenoids in coal and especially pimarane and abietane that are produced primarily by gymnosperms. Results from the coal matrix provide an opportunity to record paleoclimate changes, showing several striking and regular coal-forming cycles with distinct long- and short-term variations. Trends of δ13C coal values changes coupled with the evolution of coal-forming plants may record a gradual increase in paleo-CO 2 (p CO 2) concentration, water-table level changes and the decrease in abundance of Classopollis conifer pollen through Bajocian. This result is in accordance with the published marine carbonate records for this time, with correlation enabled through matching carbon isotope curves from the terrestrial succession at Yuqia and marine records. The similarity of the terrestrial and marine geochemical and floral record is an indication that the observed paleoclimate signal is a global phenomenon. Furthermore, the high-frequency fluctuation of δ13C coal values, along with the coal petrologic variations may record short-term changes of environmental factors (e.g. temperature or humidity/precipitation), especially during intervals when palaeobotanical composition has not fluctuated intensely. • Paleoclimate trends evaluated from terrestrial Northern Qaidam Basin, NW China • Carbon-isotope, petrological and floral record of Bajocian age Yuqia coals revealed • Isotope value distribution indicate coals largely derived from gymnosperm plants • Variations in long- and short- peat deposition cycles record paleoclimate trends • Similarity of marine geochemical and terrestrial record supports global signal [ABSTRACT FROM AUTHOR]