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Temporal patterns in Saturnidae (silk moth) and Sphingidae (hawk moth) assemblages in protected forests of central Uganda 下载免费PDF全文
Perpetra Akite Richard J. Telford Paul Waring Anne M. Akol Vigdis Vandvik 《Ecology and evolution》2015,5(8):1746-1757
Forest‐dependent biodiversity is threatened throughout the tropics by habitat loss and land‐use intensification of the matrix habitats. We resampled historic data on two moth families, known to play central roles in many ecosystem processes, to evaluate temporal changes in species richness and community structure in three protected forests in central Uganda in a rapidly changing matrix. Our results show some significant declines in the moth species richness and the relative abundance and richness of forest‐dependent species over the last 20–40 years. The observed changes in species richness and composition among different forests, ecological types, and moth groups highlight the need to repeatedly monitor biodiversity even within protected and relatively intact forests. 相似文献
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Changes in species composition of European acid grasslands observed along a gradient of nitrogen deposition 总被引:1,自引:0,他引:1
Carly Stevens Cecilia Duprè Cassandre Gaudnik Edu Dorland Nancy Dise David Gowing Albert Bleeker Didier Alard Roland Bobbink David Fowler Vigdis Vandvik Emmanuel Corcket J. Owen Mountford Per Arild Aarrestad Serge Muller Martin Diekmann 《植被学杂志》2011,22(2):207-215
Question: Which environmental variables affect floristic species composition of acid grasslands in the Atlantic biogeographic region of Europe along a gradient of atmospheric N deposition? Location: Transect across the Atlantic biogeographic region of Europe including Ireland, Great Britain, Isle of Man, France, Belgium, The Netherlands, Germany, Norway, Denmark and Sweden. Materials and Methods: In 153 acid grasslands we assessed plant and bryophyte species composition, soil chemistry (pH, base cations, metals, nitrate and ammonium concentrations, total C and N, and Olsen plant available phosphorus), climatic variables, N deposition and S deposition. Ordination and variation partitioning were used to determine the relative importance of different drivers on the species composition of the studied grasslands. Results: Climate, soil and deposition variables explained 24% of the total variation in species composition. Variance partitioning showed that soil variables explained the most variation in the data set and that climate and geographic variables accounted for slightly less variation. Deposition variables (N and S deposition) explained 9.8% of the variation in the ordination. Species positively associated with N deposition included Holcus mollis and Leontodon hispidus. Species negatively associated with N deposition included Agrostis curtisii, Leontodon autumnalis, Campanula rotundifolia and Hylocomium splendens. Conclusion: Although secondary to climate gradients and soil biogeochemistry, and not as strong as for species richness, the impact of N and S deposition on species composition can be detected in acid grasslands, influencing community composition both directly and indirectly, presumably through soil‐mediated effects. 相似文献
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Hans J. De Boeck Juliette M. G. Bloor Rien Aerts Michael Bahn Claus Beier Bridget A. Emmett Marc Estiarte Jos M. Grünzweig Aud H. Halbritter Petr Holub Anke Jentsch Karel Klem Juergen Kreyling Gyrgy Krel‐Dulay Klaus Steenberg Larsen Alexandru Milcu Jacques Roy Bjarni D. Sigurdsson Melinda D. Smith Marcelo Sternberg Vigdis Vandvik Thomas Wohlgemuth Ivan Nijs Alan K. Knapp 《Global Change Biology》2020,26(2):e6-e7
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Local temperatures inferred from plant communities suggest strong spatial buffering of climate warming across Northern Europe 总被引:1,自引:0,他引:1
Jonathan Lenoir Bente Jessen Graae Per Arild Aarrestad Inger Greve Alsos W. Scott Armbruster Gunnar Austrheim Claes Bergendorff H. John B. Birks Kari Anne Bråthen Jörg Brunet Hans Henrik Bruun Carl Johan Dahlberg Guillaume Decocq Martin Diekmann Mats Dynesius Rasmus Ejrnæs John‐Arvid Grytnes Kristoffer Hylander Kari Klanderud Miska Luoto Ann Milbau Mari Moora Bettina Nygaard Arvid Odland Virve Tuulia Ravolainen Stefanie Reinhardt Sylvi Marlen Sandvik Fride Høistad Schei James David Mervyn Speed Liv Unn Tveraabak Vigdis Vandvik Liv Guri Velle Risto Virtanen Martin Zobel Jens‐Christian Svenning 《Global Change Biology》2013,19(5):1470-1481
Recent studies from mountainous areas of small spatial extent (<2500 km2) suggest that fine‐grained thermal variability over tens or hundreds of metres exceeds much of the climate warming expected for the coming decades. Such variability in temperature provides buffering to mitigate climate‐change impacts. Is this local spatial buffering restricted to topographically complex terrains? To answer this, we here study fine‐grained thermal variability across a 2500‐km wide latitudinal gradient in Northern Europe encompassing a large array of topographic complexities. We first combined plant community data, Ellenberg temperature indicator values, locally measured temperatures (LmT) and globally interpolated temperatures (GiT) in a modelling framework to infer biologically relevant temperature conditions from plant assemblages within <1000‐m2 units (community‐inferred temperatures: CiT). We then assessed: (1) CiT range (thermal variability) within 1‐km2 units; (2) the relationship between CiT range and topographically and geographically derived predictors at 1‐km resolution; and (3) whether spatial turnover in CiT is greater than spatial turnover in GiT within 100‐km2 units. Ellenberg temperature indicator values in combination with plant assemblages explained 46–72% of variation in LmT and 92–96% of variation in GiT during the growing season (June, July, August). Growing‐season CiT range within 1‐km2 units peaked at 60–65°N and increased with terrain roughness, averaging 1.97 °C (SD = 0.84 °C) and 2.68 °C (SD = 1.26 °C) within the flattest and roughest units respectively. Complex interactions between topography‐related variables and latitude explained 35% of variation in growing‐season CiT range when accounting for sampling effort and residual spatial autocorrelation. Spatial turnover in growing‐season CiT within 100‐km2 units was, on average, 1.8 times greater (0.32 °C km?1) than spatial turnover in growing‐season GiT (0.18 °C km?1). We conclude that thermal variability within 1‐km2 units strongly increases local spatial buffering of future climate warming across Northern Europe, even in the flattest terrains. 相似文献
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Krishna M. Talasila Narve Brekka Kjersti Mangseth Daniel Stieber Lasse Evensen Gro V. Rosland Anja Torsvik Marek Wagner Simone P. Niclou Rupavathana Mahesparan Olav K. Vintermyr Rolf Bjerkvig Janice M. Nigro Hrvoje Miletic 《PloS one》2013,8(12)
Two of the signature genetic events that occur in human gliomas, EGFR amplification and IDH mutation, are poorly represented in experimental models in vitro. EGFR amplification, for example, occurs in 40 to 50% of GBM, and yet, EGFR amplification is rarely preserved in cell cultures derived from human tumors. To analyze the fate of EGFR amplified and IDH mutated cells in culture, we followed the development over time of cultures derived from human xenografts in nude rats enriched for tumor cells with EGFR amplification and of cultures derived from patient samples with IDH mutations, in serum monolayer and spheroid suspension culture, under serum and serum free conditions. We observed under serum monolayer conditions, that nestin positive or nestin and SMA double positive rat stromal cells outgrew EGFR amplified tumor cells, while serum spheroid cultures preserved tumor cells with EGFR amplification. Serum free suspension culture exhibited a more variable cell composition in that the resultant cell populations were either predominantly nestin/SOX2 co-expressing rat stromal cells or human tumor cells, or a mixture of both. The selection for nestin/SMA positive stromal cells under serum monolayer conditions was also consistently observed in human oligodendrogliomas and oligoastrocytomas with IDH mutations. Our results highlight for the first time that serum monolayer conditions can select for stromal cells instead of tumor cells in certain brain tumor subtypes. This result has an important impact on the establishment of new tumor cell cultures from brain tumors and raises the question of the proper conditions for the growth of the tumor cell populations of interest. 相似文献
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Vigdis Aas Siril S. Bakke Yuan Z. Feng Eili Tranheim Kase Jørgen Jensen Sudip Bajpeyi G. Hege Thoresen Arild C. Rustan 《Cell and tissue research》2013,354(3):671-682
Satellite cells can be isolated from skeletal muscle biopsies, activated to proliferating myoblasts and differentiated into multinuclear myotubes in culture. These cell cultures represent a model system for intact human skeletal muscle and can be modulated ex vivo. The advantages of this system are that the most relevant genetic background is available for the investigation of human disease (as opposed to rodent cell cultures), the extracellular environment can be precisely controlled and the cells are not immortalized, thereby offering the possibility of studying innate characteristics of the donor. Limitations in differentiation status (fiber type) of the cells and energy metabolism can be improved by proper treatment, such as electrical pulse stimulation to mimic exercise. This review focuses on the way that human myotubes can be employed as a tool for studying metabolism in skeletal muscles, with special attention to changes in muscle energy metabolism in obesity and type 2 diabetes. 相似文献
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