@article{ZuppingerDingleySchmidChenetal.2011, author = {Zuppinger-Dingley, D. and Schmid, Bernhard and Chen, Y. and Brandl, H. and van der Heijden, M. G. A. and Joshi, Jasmin Radha}, title = {In their native range, invasive plants are held in check by negative soil-feedbacks}, series = {Ecosphere : the magazine of the International Ecology University}, volume = {2}, journal = {Ecosphere : the magazine of the International Ecology University}, number = {5}, publisher = {Wiley}, address = {Washington}, issn = {2150-8925}, doi = {10.1890/ES11-00061.1}, pages = {12}, year = {2011}, abstract = {The ability of some plant species to dominate communities in new biogeographical ranges has been attributed to an innate higher competitive ability and release from co-evolved specialist enemies. Specifically, invasive success in the new range might be explained by release from biotic negative soil-feedbacks, which control potentially dominant species in their native range. To test this hypothesis, we grew individuals from sixteen phylogenetically paired European grassland species that became either invasive or naturalized in new ranges, in either sterilized soil or in sterilized soil with unsterilized soil inoculum from their native home range. We found that although the native members of invasive species generally performed better than those of naturalized species, these native members of invasive species also responded more negatively to native soil inoculum than did the native members of naturalized species. This supports our hypothesis that potentially invasive species in their native range are held in check by negative soil-feedbacks. However, contrary to expectation, negative soil-feedbacks in potentially invasive species were not much increased by interspecific competition. There was no significant variation among families between invasive and naturalized species regarding their feedback response (negative vs. neutral). Therefore, we conclude that the observed negative soil feedbacks in potentially invasive species may be quite widespread in European families of typical grassland species.}, language = {en} } @article{OskinovaSunEvansetal.2013, author = {Oskinova, Lida and Sun, W. and Evans, C. J. and Henault-Brunet, V. and Chu, Y.-H. and Gallagher, J. S. and Guerrero, Mart{\´i}n A. and Gruendl, R. A. and G{\"u}del, M. and Silich, S. and Chen, Y. and Naze, Y. and Hainich, Rainer and Reyes-Iturbide, J.}, title = {Discovery of x-ray emission from young suns in the small magellanic cloud}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {765}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, number = {1}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {0004-637X}, doi = {10.1088/0004-637X/765/1/73}, pages = {12}, year = {2013}, abstract = {We report the discovery of extended X-ray emission within the young star cluster NGC 602a in the Wing of the Small Magellanic Cloud (SMC) based on observations obtained with the Chandra X-Ray Observatory. X-ray emission is detected from the cluster core area with the highest stellar density and from a dusty ridge surrounding the H II region. We use a census of massive stars in the cluster to demonstrate that a cluster wind or wind-blown bubble is unlikely to provide a significant contribution to the X-ray emission detected from the central area of the cluster. We therefore suggest that X-ray emission at the cluster core originates from an ensemble of low-and solar-mass pre-main-sequence (PMS) stars, each of which would be too weak in X-rays to be detected individually. We attribute the X-ray emission from the dusty ridge to the embedded tight cluster of the newborn stars known in this area from infrared studies. Assuming that the levels of X-ray activity in young stars in the low-metallicity environment of NGC 602a are comparable to their Galactic counterparts, then the detected spatial distribution, spectral properties, and level of X-ray emission are largely consistent with those expected from low-and solar-mass PMS stars and young stellar objects (YSOs). This is the first discovery of X-ray emission attributable to PMS stars and YSOs in the SMC, which suggests that the accretion and dynamo processes in young, low-mass objects in the SMC resemble those in the Galaxy.}, language = {en} }