title: Leaf natural15N abundance and total N concentration as potential indicators of plant N nutrition in legumes and pioneer species in a rain forest of French Guiana.
abstract: The suitability of the natural15N abundance and of total N concentration of leaves as indicators of the type of plant N nutrition in a rain forest of French Guiana were tested. Leaf samples from primary legume species, non-legumes (pioneer species) and from the non-N2-fixing species Dicorynia guianensis were analyzed. Both δ15N and total leaf N varied widely (-1 ?δ15N (‰) ? 7 and 1 ? leaf N(%) ? 3.2) suggesting possible distinctions between diazotrophic and non-fixing plants. The δ15N also revealed two statistically distinct groups of non-N2-fixing species (δ15N = 5.14 ± 0.3 vs δ15N = 1.65 ± 0.17) related to the different ecological behaviors of these species in the successional processes. We conclude that the δ15N signature of plant leaves combined with their total N concentration may be relevant indicators for identifying functional groups within the community of non-N2-fixing species, as well as for detecting diazotrophy. Despite the variability in the δ15N of the non-N2-fixing species, N2-fixing groups can still be identified, provided that plants are simultaneously classified taxonomically, by their leaf δ15N and total N concentration and by the presence or absence of nodules. The variability in the δ15N of the non-fixing species is discussed.
authors.affiliation: Silvolab Guyane, Station de recherches forestières INRA BP 709, F-97387 Kourou Cedex, Guyane Française e-mail: roggy.j@cirad.fr, , , ,.
authors.forename: J C
authors.initials: JC
authors.lastname: Roggy
authors.affiliation: Silvolab Guyane, Laboratoire d'écologie végétale, ORSTOM, BP165, F-97323 Cayenne Cedex, Guyane Française, , , ,.
authors.forename: M F
authors.initials: MF
authors.lastname: Prévost
authors.affiliation: Laboratoire d'écologie microbienne des sols, CNRS UMR, 5557 Université Claude Bernard Lyon1, 43 boulevard du 11 Novembre, F-69622 Villeurbanne Cedex, France, , , , , , FR.
authors.forename: F
authors.initials: F
authors.lastname: Gourbiere
authors.affiliation: Laboratoire Central d'Analyses CNRS, Echangeur de Solaize, BP 22, F-69390 Vernaison, France, , , , , , FR.
authors.forename: H
authors.initials: H
authors.lastname: Casabianca
authors.affiliation: Laboratoire de Microbiologie forestière INRA, Centre de Nancy, F-54280 Champenoux, France, , , , , , FR.
authors.forename: J
authors.initials: J
authors.lastname: Garbaye
authors.affiliation: Laboratoire d'écologie microbienne des sols, CNRS UMR, 5557 Université Claude Bernard Lyon1, 43 boulevard du 11 Novembre, F-69622 Villeurbanne Cedex, France, , , , , , FR.
authors.forename: A M
authors.initials: AM
authors.lastname: Domenach
keywords: Key words Tropical rain forest; Pioneer species; Symbiotic N2 fixation; Tree legumes; δ15N