Zheng B.-X., Zhang H.-K., Ding K. (2018) Draft genome sequence of Rhodococcus opacus strain 04-OD7, which can mobilize phosphate. Genome Announcements. 6: 0-0.EnllaçDoi: 10.1128/genomeA.00494-18
Rhodococcus opacus strain 04-OD7 (=CCTCC AB 2017148) is a Grampositive bacterium showing inorganic phosphate solubilization capacity for the first time in the genus Rhodococcus. We present here the draft genome description of R. opacus 04-OD7 along with multiple phosphorus (P) mobilization-related genes, supporting its inorganic phosphate solubilization. © 2018 Zheng et al.
Zhu D., Ciais P., Chang J., Krinner G., Peng S., Viovy N., Peñuelas J., Zimov S. (2018) The large mean body size of mammalian herbivores explains the productivity paradox during the Last Glacial Maximum. Nature Ecology and Evolution. 2: 640-649.EnllaçDoi: 10.1038/s41559-018-0481-y
Large herbivores are a major agent in ecosystems, influencing vegetation structure, and carbon and nutrient flows. During the last glacial period, a mammoth steppe ecosystem prevailed in the unglaciated northern lands, supporting a high diversity and density of megafaunal herbivores. The apparent discrepancy between abundant megafauna and the expected low vegetation productivity under a generally harsher climate with a lower CO2 concentration, termed the productivity paradox, requires large-scale quantitative analysis using process-based ecosystem models. However, most of the current global dynamic vegetation models (DGVMs) lack explicit representation of large herbivores. Here we incorporated a grazing module in a DGVM based on physiological and demographic equations for wild large grazers, taking into account feedbacks of large grazers on vegetation. The model was applied globally for present-day and the Last Glacial Maximum (LGM). The present-day results of potential grazer biomass, combined with an empirical land-use map, infer a reduction in wild grazer biomass by 79-93% owing to anthropogenic land replacement of natural grasslands. For the LGM, we find that the larger mean body size of mammalian herbivores than today is the crucial clue to explain the productivity paradox, due to a more efficient exploitation of grass production by grazers with a large body size. © 2018 The Author(s).
Zhu, Y.-G., Gillings, M., Simonet, P., Stekel, D., Banwart, S., Penuelas, J. (2018) Human dissemination of genes and microorganisms in Earth's Critical Zone. Global Change Biology. 24: 1488-1499.EnllaçDoi: 10.1111/gcb.14003
Zwolak R., Witczuk J., Bogdziewicz M., Rychlik L., Pagacz S. (2018) Simultaneous population fluctuations of rodents in montane forests and alpine meadows suggest indirect effects of tree masting. Journal of Mammalogy. 99: 586-595.EnllaçDoi: 10.1093/jmammal/gyy034
Resource pulses can generate cross-habitat dispersal of consumers, and therefore affect organisms even in areas where the resource pulses do not occur. We investigated this phenomenon at the elevational treeline in the Carpathian Mountains, where beech (Fagus sylvatica) masting caused an increase in abundance of forest rodents and intensified their use of alpine meadows. We tested 3 hypotheses concerning the impact of forest rodent spillover on the abundance of meadow-dwelling pine voles (Microtus subterraneus): 1) the competition hypothesis: if the spillover affects pine voles mostly through intensified competitive interactions, then pine voles should decline when forest rodents reach their peak abundance, i.e., 1 year after masting; 2) the apparent competition hypothesis: if predators switch to alternative prey when populations of forest rodents collapse, then pine voles should decline 2 years after masting; and 3) the apparent mutualism hypothesis: if the increase of forest rodents temporarily releases pine voles from predatory pressure, pine voles should increase in synchrony with forest rodents-1 year after masting. Our results, while correlative in nature, supported the apparent mutualism hypothesis: 1 year after masting, both forest rodents and pine voles strongly increased their abundance. Two years after masting, when populations of forest rodents crashed, abundance of pine voles returned to pre-masting levels rather than collapse. These findings suggest that pulsed spillover, known mostly from negative effects on organisms in recipient habitats, can also create indirect positive interactions. Furthermore, they illustrate how density-dependent spillover of animals might increase the spatial scale of masting effects beyond the habitats where seeds are released. © 2018 American Society of Mammalogists, www.mammalogy.org.
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