Invasive cordgrass (Spartina spp.) in south‐eastern Australia induces island formation,salt marsh development,and carbon storage

Invasive vegetation species can lead to major changes in the geomorphology of coastal systems. Within temperate estuaries in the southern hemisphere, especially Australia and New Zealand, the cordgrass Spartina spp. has become established. These species are highly invasive, and their prolific growth leads to the development of supratidal environments in formerly intertidal and subtidal environments. Here, we quantified the impact of Spartina invasion on the geomorphology and sequestration capacity of carbon in the sediments of Anderson Inlet, Victoria, Australia. Spartina was first introduced to the area in the 1930s to aid in land reclamation and control coastal erosion associated with coastal development. We found that Spartina now dominates the intertidal areas of the Inlet and promotes accretion (18 mm/year) causing the formation of over 108 ha of supratidal islands over the past 100 years. These newly formed islands are calculated to potentially contain over 5.5 million tonnes of CO₂ equivalent carbon. Future management of the inlet and other Spartina‐dominated environments within Australian presents a dilemma for resource managers; on the one hand, Spartina is highly invasive and can outcompete native tidal marshes, thereby warranting its eradication, but on the other hand it is likely more resilient to rising sea levels and has the potential for carbon sequestration. Whether or not the potential advantages outweigh the significant habitat change that is anticipated, any management strategies will likely require additional research into costs and benefits of all ecosystem services provided by Spartina including in relation to nutrient cycling, shoreline stabilisation, and biodiversity as well as in response to the longevity of carbon found within the sediments.     

Maritime Culture in the Netherlands: accessing the late medieval maritime cultural landscapes of the north‐eastern Zuiderzee

This paper examines the theory and practice of the maritime cultural landscape in general, and projects the theoretical concepts and aspects involved on the highly dynamic late medieval north‐eastern Zuiderzee region in the Netherlands. The cultivation of land and marine erosion (floods and rising sea level) are considered as the main factors that caused the transformation of the physical landscape of this region from peatlands with freshwater basins into a tidal lagoon. As a consequence, multiple settlements drowned, large areas of land submerged, and culture and the landscape gradually became more maritime, giving the research area a cultural identity and dimension.     

Nitrogen isotopes and the trophic level of humans in archaeology

Human and domesticate animal bone collagen δ¹⁵N values in prehistory differ generally by 3‰ or more from Neolithic to post- Roman times in Northwest Europe, leading to an assumed dietary animal protein fraction of 60–80% using a standard interpretation of δ¹⁵N values. We examine the assumptions on which this model rests and the limitations of our knowledge in the analysis of δ¹⁵N values in archaeology. We have developed a set of models which, with small changes made in assumptions (on the order of 1‰), can produce substantially lower estimates of the dietary animal protein fraction for given δ¹⁵N values. We consider the implications of various dietary animal protein fractions on agricultural carrying capacities and human population densities in prehistory.     

华沙渠道与中美关系解冻:华盛顿决策内幕

在冷战的国际大背景下,尼克松政府对苏实施的“缓和”战略使得华盛顿打出“中国牌”,致力于改善同北京的关系。而1969年3月中苏边界武装冲突则为美提供了一个契机。在寻求同中国对话的渠道上,华盛顿首先想到的是华沙渠道,即第135次和136次中美大使级会谈,并为此做了充分的准备。尽管史实证明:华沙渠道的进展不像华盛顿期望的那样顺利,但基本上完成了预期的任务:表达了改善对华关系的愿望,并阐明了不会同苏联合作主宰东亚事务的立场。在华沙渠道完成了既定任务之后,华盛顿又将同北京的联络转为巴基斯坦渠道。     

从官品到俸秩:关于唐五代县之等第的考察

唐代县的等第,以户口、官品、俸秩、迁转次序等不同的标准看,有四等、五等、六等、七等、八等、十等诸说。从历时性而言,县等是不断增多的,由前期的六等逐渐发展到后期的十等,只是天宝时曾一度事实上取消下县,稍显波折。而望、紧、次赤、次畿县的出现,均与户口多寡无直接关系,更多地体现出“资地美恶”的特征。其中“次赤县”的问题尤其复杂,因其牵涉“赤县”的广义和狭义问题,综合分析,次赤县制度在传世文献中出现,不晚于唐德宗初年,很可能最迟代宗初期已经产生。而代宗末年至德宗前期形成的俸秩,对唐后期乃至五代的县之等第,也有新的影响。五代皆以户口多少定县的等第,只是不同王朝有不同的标准,繁简不一。通观唐五代县之等第,总体上呈现出从官品本位到以俸秩为准的演变路径。     

远古时期三峡地区长江洪、枯水位的考古研究(距今约15万年～1万年)

通过对三峡地区长江沿岸的考古发掘,发现了远古时期人类居住遗址的所处位置、海拔高度,尤其是遗址地层堆积中往往还叠压有洪水过后的淤积,根据这些洪水淤沙层的位置以及其上、下堆积层中包含物的年代,我们可推测出远古时期三峡地区长江发生洪水的大致年代,洪水水位的海拔高度,看看那时的河床究竟是比现在高、还是低,从而为当今人们治理长江、开发长江提供科学的证据。     

Formation of beach‐ridge plains: an appreciation of the contribution by Jack L. Davies

A robust debate among coastal geomorphologists as to the processes by which beach‐ridge plains around Australia have formed was initiated by a former President of the Institute of Australian Geographers. This review gives special consideration to the work of Jack L. Davies, whose academic contributions to coastal geomorphology in Australia have not always been appropriately acknowledged when explaining how similar plains have evolved elsewhere in the world. Davies recognised that relatively steep storm waves caused erosion (cut) on beaches, whereas less steep long‐period swell waves returned sand (fill). He considered the beach berm to be the nucleus on which a beach ridge formed, which could subsequently develop into a foredune, in contrast to cobble ridges that were deposited during storms. Offshore conditions regulate supply of sand to the shoreline, partly through effects on wave refraction, with higher rates of supply where the nearshore is shallow. It was apparent to Davies that the elevation of successive ridges might, but not necessarily, provide evidence of past changes of sea level, despite adornment by variable amounts of windblown dune sand. Morphodynamic understanding of long‐term coastal evolution, based on radiocarbon dating chronologies, has demonstrated that Australian coastal plains formed over the past ~6,000 years when sea level has been close to its present level, in contrast to several documented locations in the northern hemisphere where the sea has been rising for the past few millennia. Particularly insightful were observations by Davies that ridge formation could be influenced by a range of factors including changes in sea level, storminess, or sediment supply. These factors acting singly or in combination seem likely to change in the future. Understanding such responses remains a high priority and can be addressed by new technologies, such as light detection and ranging, optically stimulated luminescence dating, ground‐penetrating radar, and computer simulation.     

Marine trophic levels targeted between AD 300 and 1500 on the Georgia coast,USA

The marine trophic levels targeted during Swift Creek (AD 300–700) and Savannah (AD 1200–1500) occupations at the Cathead Creek site (9Mc360) and at two sites from the Kings Bay Locality (9CAM171a, 9CAM177), coastal Georgia, USA, differ in a consistent temporal and spatial pattern. Vertebrate and invertebrate remains from these three coastal sites contain similar suites of estuarine animals. However, Swift Creek peoples at these distinct hydrological settings obtained more biomass from fishes and less from molluscs compared to the subsequent Savannah occupants. The two Swift Creek faunal collections are less rich, more diverse, and more equitable than the two subsequent Savannah collections regardless of location. Furthermore, the mean trophic level is higher in the Swift Creek collections compared to the Savannah ones at both locations. These observations apply to both biomass and Minimum Number of Individuals. These differences likely are defining characteristics distinguishing the Swift Creek and the Savannah economies. More research is needed to determine the extent to which these temporal and spatial patterns are attributable to environmental and cultural variables.     

Mid‐Holocene Development of Mangrove Communities Featuring Rhizophoraceae and Geomorphic Change in the Richmond River Estuary,New South Wales,Australia

This paper describes the hitherto unreported occurrence of mid‐Holocene mangrove deposits in the Richmond River estuary, southeastern Australia, thereby providing evidence for changes in the distribution and composition of mangrove communities within a subtropical estuarine system during the Holocene. Stratigraphic, radiocarbon and palynological evidence indicates that widespread development of mangrove communities took place in the upstream reaches of the Richmond River estuary during the period 7000 to 6000 years BP. These communities maintained their habitat through substrate aggradation under the conditions of a moderate sea‐level rise, in contrast to other estuaries within the region, which generally experienced the submergence of intertidal substrates. Mangrove species belonging to the family Rhizophoraceae, most likely Bruguiera gymnorrhiza and Rhizophora stylosa, dominated these communities, in strong contrast to contemporary communities, which are dominated by Avicennia marina. Moreover, these mid‐Holocene communities were located a considerable distance upstream of the contemporary occurrences of Rhizophoraceae species within the estuary. The changes in the spatial distribution and composition of mangrove communities parallel the large‐scale evolution of the estuary driven by sea‐level variation. Shallow, buried Pleistocene terraces probably contributed to the regionally unique aggradational response of the mangrove communities and their substrates to a sea‐level rise during mid‐Holocene times.     

基于离散程度的博物馆馆藏环境温湿度中长期评估方法

温湿度是评估博物馆馆藏环境的重要指标。在越来越多的博物馆对温湿度进行监测记录的情况下,需要基于"稳定适宜"的准则,探索一种科学的评估方法,为馆藏环境温湿度的调控治理提供依据。该方法以中长期的博物馆监控数据为基础,通过计算温湿度监控数据的离散度和离散系数,并结合箱线图分析数据的分布情况,对其"稳定适宜"程度进行综合量化评估。结合四川博物院2014年的温湿度监控数据的实例,验证了该方法的有效性。研究结果表明,采用基于离散程度的中长期温湿度数据评估方法,能够为下一步的馆藏环境调控治理提供依据,有助于针对性的改善博物馆文物保存环境。