Author(s):
Neves, J. P. 
; Simões, M.P. ; Ferreira, L. F. ; Madeira, M. ; Gazarini, L. C.
Date: 2010
Persistent ID: http://hdl.handle.net/10174/3436
Origin: Repositório Científico da Universidade de Évora
Subject(s): Saltmarsh; NPP; Nutrients; Invasive species; Spartina densiflora; Arthrocnemum macrostachyum
Description
Two saltmarsh species, the native Arthrocnemum
macrostachyum (AM) and the invasive Spartina densiflora
(SD), were compared in terms of monthly variation of
above and belowground biomass, and nutrient (N, P, K, Ca,
Mg, Mn) concentrations, over 1 year, in Castro Marim
saltmarsh, Portugal. Net aboveground primary productivity
was also estimated by two different methods. Above and
belowground biomass were higher in SD than in AM and
there were distinct monthly variations in the two species.
Maximum relative growth rate was observed in the
October/January period for SD (4.92±0.36 mg g-1 day-1)
and in April/July for AM (3.37±1.26 mg g-1 day-1).
Whatever the method used, net aboveground primary
productivity was higher in SD (2,603 and 2,923 g m-2 yr-1,
respectively by the Smalley and the Wiegert and Evans
method) than in AM (692 and 1,012 g m-2 yr-1, respectively).
The turnover rate for aboveground live biomass of AM
was half the value of SD (0.8 yr-1 and 1.7 yr-1,
respectively). The N/P ratio in photosynthetic active
components and belowground biomass of AM (11 and 13)
was higher than in those of SD (7 and 10). Concentrations
of K, Ca and Mg in photosynthetic tissues of SD were
lower than in AM. Differences observed between study
species suggest that S. densiflora has better ability to use
resources and to compete with native species.
