IADIZA   20886
INSTITUTO ARGENTINO DE INVESTIGACIONES DE LAS ZONAS ARIDAS
Unidad Ejecutora - UE
artículos
Título:
Grass seed production in the central Monte desert during successive wet and dry years.
Autor/es:
POL, R, G.I. PIRK, L. MARONE
Revista:
PLANT ECOLOGY
Editorial:
SPRINGER
Referencias:
Año: 2009
ISSN:
1385-0237
Resumen:
Abstract In desert regions, water availability triggers
primary production, which determines seed production,
the composition and size of soil seed reserves
and the abundance and behaviour of seed-eating
animals. In the central Monte desert, large precipitation
events (C10 mm) account for a high proportion of
growing seasons rainfall. Our first objective here was
to assess whether and how timing and amount of seed
production of C3 and C4 perennial grasses are linked to
spring and summer precipitation pulses and to estimate
the seasonal and year-to-year variability in seed
production. Our second aim was to calculate grass
seed production and compare it with seed requirements
by granivorous animals to infer whether the animals
can exert top-down effects on plant populations. Seed
production of C3 and C4 species was triggered by
significant spring and summer rainfall, respectively.
Such distinct response may be associated with the
effect of precipitation during flower development and
seed set in both functional groups. In all species, seed
production varied among years. Rainfall pulses in the
summer triggered and positively affected the magnitude
of seed production in most C4 grasses. However,
all perennial grasses were able to produce high amount
of seeds even during a year subjected to extreme
drought, suggesting that perenniality would allow these
species to make large reproductive investment despite
harsh environmental conditions. The comparative
assessment of seed production and consumer demands
suggests that it is unlikely that granivory exerts a topdown
control on grasses in the Monte desert.