Mention de date : 2015
Journal of ecology / British Ecological Society . 103
Paru le : 01/01/2015
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Strategies for a successful plant invasion: the reproduction of Phragmites australis in north-eastern North America / Arnaud Albert in Journal of ecology, 103 (2015)
Titre : Strategies for a successful plant invasion: the reproduction of Phragmites australis in north-eastern North America Type de document : Électronique Auteurs : Arnaud Albert ; Jacques Brisson ; François Belzile ; Julie Turgeon ; Claude Lavoie Année de publication : 2015 Article en page(s) : 1529-1537 Langues : Anglais (eng) Catégories : [Géographique] Amérique du Nord
[Thématique] Plantes subspontanées, naturalisées, envahissantes
Mots-clés : Phragmites australis (Cav.) Trin. ex Steud., 1840 Résumé : Knowing the relative contribution of vegetative propagation and sexual reproduction to the dispersal and establishment of exotic plants is crucial for devising efficient control strategies. This is particularly true for the common reed (Phragmites australis), one of the most invasive species in North America. For the first time, we combined in situ field observations and genetic evidence, based on two genotyping techniques, that is microsatellite markers (SSR) and genotyping by sequencing (GBS), to determine the propagation strategies of this invader at its northern distribution limit in North America and especially in roadside ditches. Field observations revealed that, in a region where the common reed is already abundant, both seeds and plant fragments contributed to the establishment of new populations. Newly established individuals originated mostly (84%) from seeds rather than fragments, but a larger proportion of individuals originating from fragments survived the second year compared to seedlings. High genetic diversity among marsh and roadside common reed stands indicated the prime role of sexual reproduction for dispersal. The vast majority of genotypes were found in only one stand; such high genetic variability can only be explained by sexual reproduction. Half the surveyed stands comprised a single clone, suggesting that local expansion mainly occurred vegetatively. As the small proportion of SSR genotypes initially thought to be common between distant stands proved to be distinct (as revealed by GBS data), it is likely that all the stands examined were initially founded by genetically distinct individuals. Synthesis. Our study suggests that long-distance dispersal by seeds is important for the common reed, in marshes and roadsides, while both seeds and plant fragments contribute to short-distance dispersal along roads, at least in regions where the species is already abundant. The success of this invader in North America seems to be attributable to a reproduction strategy combining the advantages of sexuality with those of vegetative propagation. Moreover, this study shows that the GBS approach strongly reduces uncertainties associated with the use of a limited number of markers. This approach is especially valuable for ecologists dealing with an ever-increasing number of invaders, of which few have identified microsatellite markers.
Lien pérenne : DOI : 10.1111/1365-2745.12473
in Journal of ecology > 103 (2015) . - 1529-1537Albert, A., Brisson, J., Belzile, F., Turgeon, J., Lavoie, C. 2015. Strategies for a successful plant invasion: the reproduction of Phragmites australis in north-eastern North America. Journal of ecology, 103: 1529-1537.
Root functional parameters along a land-use gradient: evidence of a community-level economics spectrum / Iván Prieto in Journal of ecology, 103 (2015)
Titre : Root functional parameters along a land-use gradient: evidence of a community-level economics spectrum Type de document : Imprimé Auteurs : Iván Prieto ; Catherine Roumet ; Remi Cardinael ; Christian Dupraz ; Christian Jourdan ; John H. Kim ; Jean Luc Maeght ; Zhun Mao ; Alain Pierret ; Noelia Portillo ; Olivier Roupsard ; Chantanousone Thammahacksa ; Alexia Stockes Année de publication : 2015 Article en page(s) : 361-373 Langues : Anglais (eng) Catégories : [Thématique] Restauration des écosystèmes
Résumé : 1 There is a fundamental trade-off between leaf traits associated with either resource acquisition or resource conservation. This gradient of trait variation, called the economics spectrum, also applies to fine roots, but whether it is consistent for coarse roots or at the plant community level remains untested. 2 We measured a set of morphological and chemical root traits at a community level (functional parameters; FP) in 20 plant communities located along land-use intensity gradients and across three climatic zones (tropical, mediterranean and montane). We hypothesized (i) the existence of a root economics spectrum in plant communities consistent within root types (fine, < 2 mm; coarse, 2–5 mm), (ii) that variations in root FP occur with soil depths (top 20 cm of soil and 100–150 cm deep) and (iii) along land-use gradients. Root FP covaried, in line with the resource acquisition–conservation trade-off, from communities with root FP associated with resource acquisition (e.g. high specific root length, SRL; thin diameters and low root dry matter contents, RDMC) to root FP associated with resource conservation (e.g. low SRL, thick diameters and high RDMC). This pattern was consistent for both fine and coarse roots indicating a strong consistency of a trade-off between resource acquisition and conservation for plant roots. 3 Roots had different suites of traits at different depths, suggesting a disparity in root function and exploitation capacities. Shallow, fine roots were thinner, richer in nitrogen and with lower lignin concentrations associated with greater exploitation capacities compared to deep, fine roots. Shallow, coarse roots were richer in nitrogen, carbon and soluble concentrations than deep, coarse roots. 4 Fine root parameters of highly disturbed, herbaceous-dominated plant communities in poorer soils were associated with foraging strategies, that is greater SRL and lower RDMC and lignin concentration than those from less disturbed communities. Coarse roots, however, were less sensitive to the land-use gradient. 5 Synthesis. This study demonstrates the existence of a general trade-off in root construction at a community level, which operates within all root types, suggesting that all plant tissues are controlled by the trade-off between resource acquisition and conservation.
Lien pérenne : DOI : 10.1111/1365-2745.12351
in Journal of ecology > 103 (2015) . - 361-373Prieto, I., Roumet, C., Cardinael, R., Dupraz, C., Jourdan, C., Kim, JH., Maeght, J.L., Mao, Z., Pierret, A., Portillo, N., Roupsard, O., Thammahacksa, C., Stockes, A. 2015. Root functional parameters along a land-use gradient: evidence of a community-level economics spectrum. Journal of ecology, 103: 361-373.