INVESTIGADORES
MARONE Luis
artículos
Título:
Granivore impact on soil-seed reserves in the central Monte desert, Argentina
Autor/es:
MARONE, L; ROSSI, B; LOPEZ DE CASENAVE, J; LUIS MARONE
Revista:
FUNCTIONAL ECOLOGY
Referencias:
Lugar: Edimburgo; Año: 1998 vol. 12 p. 640 - 645
ISSN:
0269-8463
Resumen:
Summary
1. Mechanisms of grass- and forb-seed input and output in the central Monte desert of
Argentina were studied in 1995 to test the hypothesis that seed consumption by
autumnwinter granivores, especially birds, has qualitative as well as quantitative
effects on soil-seed reserves.
2. The abundance of perennial grass seeds in late summer soils (» 2400 seeds m2 or
0·36 g m2) remained unchanged the following early spring (» 2700 seeds m2 or
0·39 g m2), despite the incorporation of about 3000 seeds m2 or 0·71 g m2 newly
produced grass seeds during autumnwinter. Grass seeds appeared to be heavily consumed,
especially the medium-sized ones.
3. The annual forb-seed bank was about the same size in late summer (» 5500
seeds m2 or 1·34 g m2) as in early spring (» 6500 seeds m2 or 1·53 g m2). Since
forb-seed production had been relatively low (» 400 seeds m2 or 0·12 g m2), these
seeds apparently suffered negligible postdispersal losses.
4. This pattern of grass- and forb-seed loss coincides with the pattern of seed
consumption by granivorous birds on average, 93% of seed mass in bird stomachs
was from grass seeds, while only 7% was from forb seeds.
5. Further evidence of a major impact of bird foraging on seed reserves is that the
mass of particular grass seeds that was lost from soils was positively correlated with
the mass of such seeds in bird diets, and that the main target of bird consumption, i.e.
medium-sized grass seeds, suffered the highest postdispersal loss.
6. It is concluded that autumnwinter granivores in the central Monte desert, particularly
birds, mainly consume newly produced grass seeds and that they might have
major qualitative as well as quantitative impacts on soil-seed reserves.
Key-words: Granivory, granivorous birds, postdispersal seed loss, seed rain, soil-seed bank