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Myers-Smith I.H.,University of Edinburgh | Hallinger M.,University of Greifswald | Hallinger M.,Swedish University of Agricultural Sciences | Blok D.,Copenhagen University | And 20 more authors.
Earth-Science Reviews | Year: 2015

Shrubs have increased in abundance and dominance in arctic and alpine regions in recent decades. This often dramatic change, likely due to climate warming, has the potential to alter both the structure and function of tundra ecosystems. The analysis of shrub growth is improving our understanding of tundra vegetation dynamics and environmental changes. However, dendrochronological methods developed for trees, need to be adapted for the morphology and growth eccentricity of shrubs. Here, we review current and developing methods to measure radial and axial growth, estimate age, and assess growth dynamics in relation to environmental variables. Recent advances in sampling methods, analysis and applications have improved our ability to investigate growth and recruitment dynamics of shrubs. However, to extrapolate findings to the biome scale, future dendroecological work will require improved approaches that better address variation in growth within parts of the plant, among individuals within populations and between species. © 2014 Elsevier B.V. Source

Biginagwa F.J.,Roskilde University | Biginagwa F.J.,Sokoine University of Agriculture | Mayoma B.S.,Roskilde University | Shashoua Y.,Environmental Archaeology and Materials Science | And 2 more authors.
Journal of Great Lakes Research | Year: 2016

Microplastic contamination in the African Great Lakes is currently unreported, and compared to other regions of the world little is known about the occurrence of microplastics in African waters and their fauna. The present study was conducted in the Mwanza region of Tanzania, located on the southern shore of Lake Victoria. The gastrointestinal tracts of locally fished Nile perch (Lates niloticus) and Nile tilapia (Oreochromis niloticus) were examined for plastics. Plastics were confirmed in 20% of fish from each species by Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy. A variety of polymer types were identified with likely sources being urban waste and consumer use. Although further research is required to fully assess the impact of plastic pollution in this region, our study is the first to report the presence of microplastics in Africa's Great Lakes and within the fish species that inhabit them. © 2015 International Association for Great Lakes Research. Source

Mortensen M.F.,Environmental Archaeology and Materials Science | Henriksen P.S.,Environmental Archaeology and Materials Science | Bennike O.,Geological Survey of Denmark
Vegetation History and Archaeobotany | Year: 2014

The immigration of woody plants, especially Betula (tree birch), is examined in relation to geomorphological regions in a compilation of Late-glacial plant macrofossil records from Denmark. The immigration of trees led to a large ecological transformation of the landscape and had a major effect on the flora and fauna available to Palaeolithic people. We show that soil type was a controlling factor in the development of vegetation during the Allerød and Younger Dryas periods. Following the first immigration of trees during the Allerød period, woods became established in the eastern part of Denmark, where ice advances from the Baltic had deposited calcareous and clayey sediments. The western and northern parts of Denmark that are characterised by more sandy and non-calcareous sediments remained treeless throughout the whole Late-glacial period. Finds from the Bromme Culture are concentrated in the region which was wooded, suggesting that the regional variable environment allowed local adaptations using the diverse resources available. © 2014 The Author(s). Source

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