Above- and below-ground macrophyte production in Scirpus tidal marshes of the St. Lawrence estuary, Quebec

Abstract

1988. Above-and below-ground macrophyte production in Scirpus tidal marshes of the St. Lawrence estuary, Quebec. Can. J. Bot. 66: 955 -962. Above-and below-ground standing crops as well as primary production of several macrophytes were estimated in Scirpus marshes along the south shore of the St. Lawrence River estuary in Quebec. Aboveground standing crop was measured by clipping vegetation, while belowground standing crop was estimated by soil coring. Seasonal variation of live and dead standing crops was first determined for different plant species. The root:shoot mass ratio was then examined and related to the life history of each species. Total aboveground production varied from 74 to 627 g ash-free dry mass. m-2. year-' among different plant communities, whereas belowground production was lower, with estimates varying between 38 and 244 g . m+. year-'.Production was lower along the St. Lawrence estuary than in other types of marshes located farther south. GIROUX, J.-F., et BBDARD, J. 1988. Above-and below-ground macrophyte production in Scirpus tidal marshes of the St.Lawrence estuary, Quebec. Can. J. Bot. 66 : 955 -962. La phytomasse aCrienne et souterraine ainsi que la production primaire de plusieurs macrophytes ont Ct C estimCes dans les marais i scirpe localisCs le long de la rive sud de l'estuaire du Fleuve Saint-Laurent au QuCbec. La phytomasse aCrienne fut mesurCe en rkcoltant la vCgCtation alors que la phytomasse souterraine fut estimCe en prClevant des carottes. La variation saisonnikre de la phytomasse vivante et morte a d'abord Ct C dCterminCe pour les diffkrentes espkces vCgCtales prksentes. Le rapport entre la masse des parties souterraines et aCriennes a ensuite Ct C examin6 et mis en relation avec la biologie de chaque espkce. Parmi les diffkrentes communautCs vCgCtales, la production akrienne variait entre 74 et 627 g de matikre skche sans cendre. m'2. an-' alors que la production souterraine Ctait plus basse avec des estimCs entre 38 et 244 g . m-2. an-'. La production des plantes de l'estuaire du Saint-Laurent Ctait plus basse que celle rapportCe pour des marais situCs plus au sud.

Foraging ecology of Greater Snow Geese, Chen caerulescens atlantica, in different Scirpus marsh plant communities

“…They were determined mainly on the basis of plant species abundance and length of time submerged by tide. Communities A and D of this study correspond, respectively, to communities 3 and 4 described by Giroux and Bédard (1988c). These plant communities are typical of all tidal Scirpus marshes along the St. Lawrence River (see Giroux and 1988c).…”

“…Depending on physical conditions (submersion time, substrate characteristics, soil texture, etc. ), several plant communities could be identified in the Scirpus lower marsh (see Giroux and Bédard 1988c).…”

“…We made our surveys during autumn 1985, 1986 and spring 1986, 1987. Thirteen permanent transects were established systematically across the four main plant communities (named A, B, C and D) of the lower marsh as previously identified by Giroux and Bédard (1988c)(Figure 1). They were determined mainly on the basis of plant species abundance and length of time submerged by tide.…”

“…The sum of the biomass for each species present (derived by multiplying individual stem biomass estimates by stem density) yielded the total above-ground biomass for each quadrat. In Scirpus marshes, peak aboveground biomass in August is considered a good predictor of net above-ground primary production (NAPP) which, in turn, is closely related to net below-ground production (NBPP) (Giroux and Bédard 1988c). In the present paper, all estimates of NBPP are presented on an ash-free dry-mass basis.…”

Géomorphologie et diversité végétale des marais du Cap Marteau et de l’Isle-Verte, estuaire du Saint-Laurent, Québec

“…Les recherches antérieures sur les marais maritimes de l'estuaire et du golfe du Saint-Laurent font état d'une description des formations végétales (Prat, 1933 ;Couillard et Grondin, 1986), de la dynamique sédimentaire (Morin, 1981 ;Drapeau et Morin, 1981 ;Drapeau, 1992 ;Sérodes et Dubé, 1983 ;Sérodes et Troude, 1984 ;Troude et Sérodes, 1990 ;Dionne, 2002), de l'influence du temps de submersion de la végétation (Sérodes et al, 1985), des processus d'érosion des marais (Gauthier et Goudreau 1983 ;Dionne, 1986Dionne, , 2000Dionne, , 2001a, de l'influence des glaces littorales (Dionne, 1969(Dionne, , 1972a(Dionne, , 1984(Dionne, , 1985(Dionne, , 1989Troude et Sérodes, 1988), de la productivité primaire (Giroux et Bédard, 1987), du recyclage des contaminants par les marais (Deschênes et Sérodes, 1986) et de leur reconstitution historique et paléoécologique (Garneau, 1998 ;Hatvany, 2003). Peu d'études ont quantifié la diversité végétale des marais maritimes tout en établissant son lien entre la répartition et la variabilité spatiale des caractéristiques physiques du milieu.…”