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Growth pattern and modular reiteration of a hardy coloniser Polytrichum commune Hedw. / Pierre Corradini in Plant ecology, vol. 143, n°1 (Année 1999)

Public [article]  inPlant ecology > vol. 143, n°1 (Année 1999) . - pp. 67-76 Titre : Growth pattern and modular reiteration of a hardy coloniser Polytrichum commune Hedw. Type de document : texte imprimé Auteurs : Pierre Corradini, Auteur ; Bernard Clément, Auteur Année de publication : 1999 Article en page(s) : pp. 67-76 Langues : Anglais (eng) Catégories : [ZG] FINISTERE (29) [habitats/milieux] 3 - Landes, fruticées et prairies Mots-clés : colonisation  après incendie  population biologique Résumé : "Heathlands in Brittany are subject to recurrent summer burning. Recolonisation after large fires begins with bryophytes, but species composition during succession may be altered by colonies of Polytrichum commune Hedw. which appears to be able to prevent reestablishment of the typical heathland formation. Three complementary levels of investigation were adopted in attempting to understand how P. commune, manages to persist and succeed in space open to rapid saturation. Analysis at the level of the local plant community, showed radical changes in the distribution and composition of the herbaceous and muscinal layers over two years. Between May 1992 and May 1994, P. commune cover increased from 13% to 77% accompanied by an appreciable decrease in other pioneer species. We compared individual colony growth of P. commune with that of Polytrichum piliferum, another pioneer moss. In both species, horizontal and vertical growth occurred in spring and autumn. During 1995, P. commune colony diameter had increased by a factor of 4.0 compared with 3.6 for P. piliferum. Over the same interval, colony height increased by a factor of 1.3 for P. commune compared with 1.8 for P. piliferum. Analysis at the level of the module showed that 79% of experimentally cultured stems produced branches, 25% producing a single branch, 32% two branches, and 25% 4 to 7 branches. The lower the location of new branches on culture stems, the longer their leafed section and the greater their overall length. These new branches were morphologically and functionally new ramets. These observations on P. commune conform to the inhibition model of community succession (Connell & Slatyer 1977). Successional patterns recorded in the present study could be interpreted in terms of differences in species colony growth ability. Dense colony growth would allow a species to saturate one of the more important ecosystem compartment. Polytric capacity to grow simultaneously and efficiently in the few centimetres in and above the soil surface could prevent seedling establishment and decrease fitness of coexisting Poaceae." (source : auteurs) Type de publication : périodique Référence biblio : Corradini P., Clément B., 1999 - Growth pattern and modular reiteration of a hardy coloniser Polytrichum commune Hedw. Plant ecology, 143 (1) : 67-76. ID PMB : 71300 Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=71300 [article]

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