Human transformations of the Wadden Sea ecosystem through time: a synthesis

Todayrsquos Wadden Sea is a heavily human-altered ecosystem. Shaped by natural forces since its origin 7,500 years ago, humans gradually gained dominance in influencing ecosystem structure and functioning. Here, we reconstruct the timeline of human impacts and the history of ecological changes in the Wadden Sea. We then discuss the ecosystem and societal consequences of observed changes, and conclude with management implications. Human influences have intensified and multiplied over time. Large-scale habitat transformation over the last 1,000 years has eliminated diverse terrestrial, freshwater, brackish and marine habitats. Intensive exploitation of everything from oysters to whales has depleted most large predators and habitat-building species since medieval times. In the twentieth century, pollution, eutrophication, species invasions and, presumably, climate change have had marked impacts on the Wadden Sea flora and fauna. Yet habitat loss and overexploitation were the two main causes for the extinction or severe depletion of 144 species (~20% of total macrobiota). The loss of biodiversity, large predators, special habitats, filter and storage capacity, and degradation in water quality have led to a simplification and homogenisation of the food web structure and ecosystem functioning that has affected the Wadden Sea ecosystem and coastal societies alike. Recent conservation efforts have reversed some negative trends by enabling some birds and mammals to recover and by creating new economic options for society. The Wadden Sea history provides a unique long-term perspective on ecological change, new objectives for conservation, restoration and management, and an ecological baseline that allows us to envision a rich, productive and diverse Wadden Sea ecosystem and coastal society

Transcriptome analysis of secondary cell wall development in Medicago truncatula

This article describes a transcriptome microarray assay and high through-put quantitative real time PCR analysis of Medicago truncatula

Postglacial climate in the St. Lawrence lowlands, southern Quebec: pollen and lake-level evidence

International audiencePollen and lake-level data are used to reconstruct past climate changes in the St. Lawrence lowlands, southern Quebec. Past lake-level changes are assessed from sedimentological, pollen and macrofossil records from a single shallow-water core from Lac Hertel, which lies in the central part of the studied area. Three low lake-level phases are recognised: prior to 8000, 7600-6600 and 4800-3400 cal. BP. The modern analogue method is applied to pollen data from seven well-dated sites from the St. Lawrence lowlands and adjacent mountain areas, constrained and unconstrained by lake-level changes. The reconstructed climate changes are congruent with the pattern of climate changes known from eastern North America: a dry and cold late-glacial episode due to the presence of pro-glacial lakes and seas; a rapid warming between 12500 and 11 000 cal. BP possibly caused by increasing summer insolation; a dry period from 10 000 to 6500 cal. BP; a brief cooling between 9000 and 8000 cal. BP, possibly related to a summer cooling of Arctic airmasses; a temperature maximum around 8000 cal. BP; and finally, a progressive decrease in summer temperature and an increase in (winter?) precipitation over the 4500 last years. These results show that it is possible to reveal seasonal patterns in climate by combining pollen and lake-level data. (C) 2002 Elsevier Science B.V. All rights reserved