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Disturbance is the key to plant invasions in cold environments / Jonas J. Lembrechts in Proceedings of the National Academy of Sciences of the United States of America, 113 (49) (2016) 

Public Citation [article]  inProceedings of the National Academy of Sciences of the United States of America > 113 (49) (2016) . - 14061-14066 Titre : Disturbance is the key to plant invasions in cold environments Type de document : Imprimé Auteurs : Jonas J. Lembrechts ; Aníbal Pauchard ; Jonathan Lenoir ; Martin A. Nuñez ; Charly Geron ; Arne Ven ; Pablo Bravo-Monasterio ; Ernesto Teneb ; Ivan Nijs ; Ann Milbau Année de publication : 2016 Article en page(s) : 14061-14066 Langues : Français (fre) Catégories : [CBNPMP-Thématique] Plantes subspontanées, naturalisées, envahissantes [LOTERRE-Biodiversité] Changement climatique Résumé : Until now, nonnative plant species were rarely found at high elevations and latitudes. However, partly because of climate warming, biological invasions are now on the rise in these extremely cold environments. These plant invasions make it timely to undertake a thorough experimental assessment of what has previously been holding them back. This knowledge is key to developing efficient management of the increasing risks of cold-climate invasions. Here, we integrate human interventions (i.e., disturbance, nutrient addition, and propagule input) and climatic factors (i.e., temperature) into one seed-addition experiment across two continents: the subantarctic Andes and subarctic Scandinavian mountains (Scandes), to disentangle their roles in limiting or favoring plant invasions. Disturbance was found as the main determinant of plant invader success (i.e., establishment, growth, and flowering) along the entire cold-climate gradient, explaining 40–60% of the total variance in our models, with no indication of any facilitative effect from the native vegetation. Higher nutrient levels additionally stimulated biomass production and flowering. Establishment and flowering displayed a hump-shaped response with increasing elevation, suggesting that competition is the main limit on invader success at low elevations, as opposed to low-growing-season temperatures at high elevations. Our experiment showed, however, that nonnative plants can establish, grow, and flower well above their current elevational limits in high-latitude mountains. We thus argue that cold-climate ecosystems are likely to see rapid increases in plant invasions in the near future as a result of a synergistic interaction between increasing human-mediated disturbances and climate warming. Lien pérenne : DOI : 10.1073/pnas.1608980113 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=150057 Lembrechts, Jonas J., Pauchard, Aníbal, Lenoir, Jonathan, Nuñez, Martin A., Geron, Charly, Ven, Arne, Bravo-Monasterio, Pablo, Teneb, Ernesto, Nijs, Ivan, Milbau, Ann 2016 Disturbance is the key to plant invasions in cold environments. Proceedings of the National Academy of Sciences of the United States of America, 113(49): 14061-14066.

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Microclimate variability in alpine ecosystems as stepping stones for non-native plant establishment above their current elevational limit / Jonas J. Lembrechts in Ecography, 41 (6) (2018) 

Public Citation [article]  inEcography > 41 (6) (2018) . - 900-909 Titre : Microclimate variability in alpine ecosystems as stepping stones for non-native plant establishment above their current elevational limit Type de document : Imprimé Auteurs : Jonas J. Lembrechts ; Jonathan Lenoir ; Martin A. Nuñez ; Aníbal Pauchard ; Charly Geron ; Gilles Bussé ; Ann Milbau ; Ivan Nijs Année de publication : 2018 Article en page(s) : 900-909 Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Enjeux de conservation des lacs d'altitude Résumé : Alpine environments are currently relatively free from non-native plant species, although their presence and abundance have recently been on the rise. It is however still unclear whether the observed low invasion levels in these areas are due to an inherent resistance of the alpine zone to invasions or whether an exponential increase in invasion is just a matter of time. Using a seed-addition experiment on north- and south-facing slopes (cf. microclimatic gradient) on two mountains in subarctic Sweden, we tested the establishment of six non-native species at an elevation above their current distribution limits and under experimentally enhanced anthropogenic pressures (disturbance, added nutrients and increased propagule pressure). We found a large microclimatic variability in cumulative growing degree days (GDD) (range  500.77°C, SD  120.70°C) due to both physiographic (e.g. aspect) and biophysical (e.g. vegetation cover) features, the latter being altered by the experimental disturbance. Non-native species establishment and biomass production were positively correlated with GDD along the studied microclimatic gradient. However, even though establishment on the north-facing slopes caught up with that on the south-facing slopes throughout the growing season, biomass production was limited on the north-facing slopes due to a shorter growing season. On top of this microclimatic effect, all experimentally imposed anthropogenic factors enhanced non-native species success. The observed microclimatic effect indicates a potential for non-native species to use warm microsites as stepping stones for their establishment towards the cold end of the gradient. Combined with anthropogenic pressures this result suggests an increasing risk for plant invasion in cold ecosystems, as such stepping stones in alpine ecosystems are likely to be more common in a future that will combine a warming climate with persistent anthropogenic pressures. Lien pérenne : DOI : 10.1111/ecog.03263 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=150983 Lembrechts, Jonas J., Lenoir, Jonathan, Nuñez, Martin A., Pauchard, Aníbal, Geron, Charly, Bussé, Gilles, Milbau, Ann, Nijs, Ivan 2018 Microclimate variability in alpine ecosystems as stepping stones for non-native plant establishment above their current elevational limit. Ecography, 41(6): 900-909.

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Consultable Article (2018) URL