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OXYGEN RELATIONS OF THE ROOT NODULES OF ALNUS RUBRA BONG. 总被引:2,自引:1,他引:1
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Sutherland WJ Bardsley S Bennun L Clout M Côté IM Depledge MH Dicks LV Dobson AP Fellman L Fleishman E Gibbons DW Impey AJ Lawton JH Lickorish F Lindenmayer DB Lovejoy TE Nally RM Madgwick J Peck LS Pretty J Prior SV Redford KH Scharlemann JP Spalding M Watkinson AR 《Trends in ecology & evolution》2011,26(1):10-16
This review describes outcomes of a 2010 horizon-scanning exercise building upon the first exercise conducted in 2009. The aim of both horizon scans was to identify emerging issues that could have substantial impacts on the conservation of biological diversity, and to do so sufficiently early to encourage policy-relevant, practical research on those issues. Our group included professional horizon scanners and researchers affiliated with universities and non- and inter-governmental organizations, including specialists on topics such as invasive species, wildlife diseases and coral reefs. We identified 15 nascent issues, including new greenhouse gases, genetic techniques to eradicate mosquitoes, milk consumption in Asia and societal pessimism. 相似文献
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Megan R. McCusker Nicholas E. Mandrak Bashir Egeh Nathan R. Lovejoy 《Conservation Genetics》2014,15(2):343-353
The Pugnose Shiner is a small minnow with a fragmented distribution across the Great Lakes and Upper Mississippi River in North America. The species is listed federally as endangered in Canada, and in the United States its status varies by state, from Special Concern to Endangered (as well as Extirpated). We conducted a thorough genetic assessment of the Pugnose Shiner using both microsatellite loci and mitochondrial DNA collected for samples across the species range. Our results indicate high levels of population differentiation suggesting restricted dispersal, in some cases at very small geographical scales. We also found strong evidence of small effective population sizes and one case of a genetic bottleneck. Although significant range-wide genetic variation was observed in both microsatellite loci and mitochondrial DNA, the species is best characterized as a single evolutionarily significant unit for conservation purposes. 相似文献
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Crampton WG Lovejoy NR Waddell JC 《Evolution; international journal of organic evolution》2011,65(6):1650-1666
The reproductive signals of two or more taxa may diverge in areas of sympatry, due to selection against costly reproductive interference. This divergence, termed reproductive character displacement (RCD), is expected in species-rich assemblages, where interspecific signal partitioning among closely related species is common. However, RCD is usually documented from simple two-taxon cases, via geographical tests for greater divergence of reproductive traits in sympatry than in allopatry. We propose a novel approach to recognizing and understanding RCD in multi-species communities--one that traces the displacement of signals within multivariate signal space during the ontogeny of individual animals. We argue that a case for RCD can be made if the amount of signal displacement between a pair of species after maturation is negatively correlated to distance in signal space before maturation. Our application of this approach, using a dataset of communication signals from a sympatric Amazonian assemblage of the electric fish genus Gymnotus, provides strong evidence for RCD among multiple species. We argue that RCD arose from the costs of heterospecific mismating, but interacted with sexual selection--favoring the evolution of conspicuous male signals that not only serve for mate-choice, but which simultaneously facilitate species recognition. 相似文献
128.
Permafrost thawing in lowland Arctic tundra results in a polygonal patterned landscape and the formation of numerous small ponds. These ponds emit biologically mediated carbon dioxide (CO2) and methane (CH4). Their greenhouse gas (GHG) emissions are variable, for reasons that are not well understood. Emissions are related to a balance between GHG producers and consumers, as well as to physical properties of the water column controlling gas exchange rates with the atmosphere. Here, we investigated the bacterial diversity of polygonal and runnel ponds, two geomorphologically distinct pond types commonly found in continuous permafrost regions. Using a combination of 16S rRNA Sanger sequencing and high-throughput amplicon sequencing, we found that bacterial communities in overlying waters were clearly dominated by carbon degraders and were similar in both pond types, despite their variable physical and chemical properties. However, surface sediment communities in the two pond types were significantly different. Polygonal pond sediment was colonized by carbon degraders (46–29 %), cyanobacteria (20–27 %) that take up CO2 and produce oxygen, and methanotrophs (11–20 %) that consume CH4 and require oxygen. In contrast, cyanobacteria were effectively absent from the surface sediment of runnel ponds, which in addition to carbon degraders (65–81 %), were colonized by purple non-sulfur bacteria (5–21 %), and by fewer methanotrophs (1–5 %). The link between the methanotrophic community and the type of ponds could potentially be used to improve upscale estimates of GHG emissions based on landscape morphology in such remote regions. 相似文献
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Michael E. Bush C. Owen Lovejoy Donald C. Johanson Yves Coppens 《American journal of physical anthropology》1982,57(4):651-677
The fossil hominid hand bone collection from the Pliocene Hadar Formation, Ethiopia, is described anatomically. These hand bones, all from A.L. (Afar Locality) 333 and 333w, constitute the largest sample of hominid manus remains thus far recovered from the Plio-Pleistocene of Africa. 相似文献