Granivory in southern South American deserts: conceptual issues and current evidence

L. MARONE; J. LOPEZ DE CASENAVE; V. R. CUETO

BIOSCIENCE

American Institute of Biological Sciences

Año: 2000 vol. 50 p. 123 - 132

0006-3568

Granivory may have a significant community role in the Monte and other South American deserts, despite the probable lack of highly specialized seedeaters. Natural rates of seed consumption and the abundance and diversity of granivorous assemblages in some South American deserts may have been underestimated in the past. Current evidence suggests that birds and ants are important seedeaters during the colder and warmer months, respectively, and that the role of small mammals as granivores deserves more detailed assessment in the central Monte desert of Argentina. These results should be readily incorporated into comparative analyses on desert granivory world-wide because they modify the previous scenario of granivory patterns, and will correspondingly allow to distinguish more accurately between generalizable (ecological) from idiosyncratic (historical) processes molding desert communities. The relative importance of seed consumption or of granivorous assemblages in deserts around the world cannot be assessed through one research approach alone. Instead, research programs that include multiple approaches involving redundancy and crosschecks of hypotheses and methods may lead most objectively to synthesis and integration through the establishment of robust conclusions. Furthermore, any such approach should involve long-term studies that take into account the spatial and temporal variability of natural communities.