<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Acácio, Vanda</style></author><author><style face="normal" font="default" size="100%">Holmgren, Milena</style></author><author><style face="normal" font="default" size="100%">Jansen, Patrick a.</style></author><author><style face="normal" font="default" size="100%">Schrotter, Ondrej</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Multiple Recruitment Limitation Causes Arrested Succession in Mediterranean Cork Oak Systems</style></title><secondary-title><style face="normal" font="default" size="100%">Ecosystems</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">alternative states</style></keyword><keyword><style  face="normal" font="default" size="100%">Cistus ladanifer</style></keyword><keyword><style  face="normal" font="default" size="100%">Facilitation</style></keyword><keyword><style  face="normal" font="default" size="100%">forest regeneration</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</style></keyword><keyword><style  face="normal" font="default" size="100%">seed dispersal</style></keyword><keyword><style  face="normal" font="default" size="100%">seed predation</style></keyword><keyword><style  face="normal" font="default" size="100%">seedling establishment</style></keyword><keyword><style  face="normal" font="default" size="100%">Shrub encroachment</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2007</style></year></dates><volume><style face="normal" font="default" size="100%">10</style></volume><pages><style face="normal" font="default" size="100%">1220-1230</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Lack of tree regeneration and persistency of species-poor shrublands represent a growing problem across Mediterranean evergreen oak forests. What constrains forest regeneration is poorly understood, and restoration attempts have been largely unsuccessful. We assessed the contribution of four different mechanisms of tree recruitment limitation (that is, source, dispersal, germination, and establishment) in a cork oak (Quercus suber) system in southern Portugal. Using a combination of ﬁeld studies and experiments, we quantiﬁed seed production, seed removal and dispersal, seed survival and germination, seedling establishment and survival, as well as cork oak natural regeneration for the three dominant vegetation types in this system (Cistus ladanifer shrubland, oak forest, and oak savanna). We found that all four forms of cork oak recruitment limitation were signiﬁcantly more severe in shrublands than in oak forests and savannas, so that oak seedling recruitment in shrubland was impeded in multiple ways. Our results explain why transitions from shrublands to oak savannas and forests are extremely difﬁcult, and that the release from arrested succession in this system requires the simultaneous relief of multiple constraints on recruitment limitation in the early life history of oaks. These results have important implications for the restoration</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Acácio, Vanda</style></author><author><style face="normal" font="default" size="100%">Holmgren, Milena</style></author><author><style face="normal" font="default" size="100%">Jansen, Patrick a</style></author><author><style face="normal" font="default" size="100%">Schrotter, Ondrej</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Multiple Recruitment Limitation Causes Arrested Succession in Mediterranean Cork Oak Systems</style></title><secondary-title><style face="normal" font="default" size="100%">Ecosystems</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">alternative states</style></keyword><keyword><style  face="normal" font="default" size="100%">Cistus ladanifer</style></keyword><keyword><style  face="normal" font="default" size="100%">Facilitation</style></keyword><keyword><style  face="normal" font="default" size="100%">forest regeneration</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</style></keyword><keyword><style  face="normal" font="default" size="100%">seed dispersal</style></keyword><keyword><style  face="normal" font="default" size="100%">seed predation</style></keyword><keyword><style  face="normal" font="default" size="100%">seedling establishment</style></keyword><keyword><style  face="normal" font="default" size="100%">Shrub encroachment</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2007</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2007///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/index/10.1007/s10021-007-9089-9</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">10</style></volume><pages><style face="normal" font="default" size="100%">1220 - 1230</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Lack of tree regeneration and persistency of species-poor shrublands represent a growing problem across Mediterranean evergreen oak forests. What constrains forest regeneration is poorly understood, and restoration attempts have been largely unsuccessful. We assessed the contribution of four different mechanisms of tree recruitment limitation (that is, source, dispersal, germination, and establishment) in a cork oak (Quercus suber) system in southern Portugal. Using a combination of ﬁeld studies and experiments, we quantiﬁed seed production, seed removal and dispersal, seed survival and germination, seedling establishment and survival, as well as cork oak natural regeneration for the three dominant vegetation types in this system (Cistus ladanifer shrubland, oak forest, and oak savanna). We found that all four forms of cork oak recruitment limitation were signiﬁcantly more severe in shrublands than in oak forests and savannas, so that oak seedling recruitment in shrubland was impeded in multiple ways. Our results explain why transitions from shrublands to oak savannas and forests are extremely difﬁcult, and that the release from arrested succession in this system requires the simultaneous relief of multiple constraints on recruitment limitation in the early life history of oaks. These results have important implications for the restoration</style></abstract><issue><style face="normal" font="default" size="100%">7</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Hättenschwiler, S</style></author><author><style face="normal" font="default" size="100%">Miglietta, F</style></author><author><style face="normal" font="default" size="100%">Raschi, A</style></author><author><style face="normal" font="default" size="100%">Körner, C</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Thirty years of in situ tree growth under elevated CO2: a model for future forest responses?</style></title><secondary-title><style face="normal" font="default" size="100%">GLOBAL CHANGE BIOLOGY</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Basal area</style></keyword><keyword><style  face="normal" font="default" size="100%">Dendrochronology</style></keyword><keyword><style  face="normal" font="default" size="100%">forest regeneration</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean forests</style></keyword><keyword><style  face="normal" font="default" size="100%">natural CO2 springs</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Tree ring</style></keyword><keyword><style  face="normal" font="default" size="100%">water relations</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1997</style></year></dates><publisher><style face="normal" font="default" size="100%">BLACKWELL SCIENCE LTD</style></publisher><pub-location><style face="normal" font="default" size="100%">P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE</style></pub-location><volume><style face="normal" font="default" size="100%">3</style></volume><pages><style face="normal" font="default" size="100%">463-471</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Rising concentrations of atmospheric carbon dioxide have been predicted to stimulate the growth of forest trees. However, long-term effects on trees growing to maturity and to canopy closure while exposed to elevated CO2 have never been examined. We compared tree ring chronologies of Mediterranean Quercus ilex which have been continuously exposed to elevated CO2 (around 650 mu mol mol(-1)) since they were seedlings, near two separate natural CO2 springs with those from trees at nearby ambient-CO2 `control' sites. Trees grown under high CO2 for 30 years (1964-93) showed a 12% greater final radial stem width than those growing at the ambient-CO2 control sites. However, this stimulation was largely due to responses when trees were young. By the time trees were 25-30 y old the annual difference in tree ring width between low and high CO2 grown trees had disappeared. At any given tree age, elevated CO2 had a relatively greater positive effect on tree ring width in years with a dry spring compared to years with more rainfall between April and May. This indicates a beneficial effect of elevated CO2 on tree water relations under drought stress. Our data suggest that the early regeneration phase of forest stands can be accelerated in CO2-enriched atmospheres and that maximum biomass per land area may be reached sooner than under lower CO2 concentrations. In our study, high CO2 grown Q. ilex trees reached the same stem basal area at the age of 26 y as control trees at 29 y,i.e. three years earlier (faster turnover of carbon?). Reliable predictions of the future development of forests need to account for the variable responses of trees over their entire lifetime. Such responses to elevated CO2 can presently only be assessed at such unique field sites.</style></abstract></record></records></xml>