Submerged macrophyte seed bank in a Mediterranean temporary marsh: abundance and relationship with established vegetation.
The abundance and composition of the submerged macrophyte seed bank in the Doñana marsh (southwestern Spain) was evaluated to assess its relationship with the overlying vegetation. The results obtained demonstrate the existence of a dense seed-bank, both in terms of the number of seeds and their biomass, which represented about 10% (5% for angiosperms and >20% for Charophyta) of the total plant biomass, which ensures the maintenance of the annual submerged macrophyte populations of the seasonally inundated Donñana marsh. Seed bank and established vegetation were coupled, as reflected in the existence of significant correlations between their structure and abundance. This coupling was lacking for Charophyta, whose oospores are widespread and abundant across the marsh, even at locations where they are absent, or rare, in the established vegetation. These differences between the seed bank of annual angiosperms and Charophyta appear to reflect, in part, structural differences between angiosperm seeds and Charophyta oospores, with important ecological consequences. An important aspect of these differences is the allocation of Charophyta reproductive effort to many small propagules lacking embryo storage, compared to those of angiosperms, which ensures their efficient dispersal and numerical abundance in the seed bank.
Station Biologique de la Tour du Valat, F-13200, Le Sambuc, France.
P
P
Grillas
Departamento de Biologia Vegetal y Ecologia, Universidad de Sevilla, Spain.
P
P
Garcia-Murillo
Freshwater Biological Laboratory, University of Copenhagen, 51 Helsingørsgade, 3400, Hillerød, Denmark.
O
O
Geertz-Hansen
Centro de Estudios Avanzados de Blanes, Camino de Santa Barbara s/n, 17300, Blanes, Girona, Spain.
N
N
Marbá
Departamento de Ecologia, Universidad Autonoma, 28049, Madrid, Spain.
C
C
Montes
Centro de Estudios Avanzados de Blanes, Camino de Santa Barbara s/n, 17300, Blanes, Girona, Spain.
C M
CM
Duarte
Station Biologique de la Tour du Valat, F-13200, Le Sambuc, France.
L
L
Tan Ham
Station Biologique de la Tour du Valat, F-13200, Le Sambuc, France.
A
A
Grossmann
Annuals; Seed bank; Seed size; Submerged macrophytes; Temporary Mediterranean marsh