IADIZA   20886
INSTITUTO ARGENTINO DE INVESTIGACIONES DE LAS ZONAS ARIDAS
Unidad Ejecutora - UE
artículos
Título:
Enhanced plant-pollinator interactions and tree reproduction after suppression of anthropogenic degradation in an arid ecosystem
Autor/es:
ASCHERO, V.; VÁZQUEZ, D. P.
Revista:
AUSTRAL ECOLOGY
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Año: 2009 vol. 34 p. 901 - 907
ISSN:
1442-9985
Resumen:
Anthropogenic activities usually trigger changes in the population density of plants. Thus, land management practices can influence density-dependent demographic parameters and species interactions.We investigated plant-pollinator interactions and reproduction in Prosopis flexuosa, the largest tree species in the Central Monte desert of Argentina, an important economic and cultural resource for humans and a functionally prominent species.We hypothesized that reproductive output of P. flexuosa would be limited at low densities, and that exclusion of catle grazing would enhance population density and consequently interaction frequency with pollinators and reproductive success.The study was conducted in and around Ñacuñán Biosphere Reserve (Mendoza, Argentina), where cattle grazing has been excluded for over 35 years.Working in five pairs of protected and cattle grazed 1-ha plots, we recorded density of adult trees, pollinator visitation frequency to inflorescences and seeds per inflorescence in focal trees. Adult tree density was higher in protected plots than in cattle grazed plots. Density of reproductive trees was positively correlated with seed production, suggesting positive density dependence for reproduction (Allee effect). Pollinator visitation to inflorescences and seed production was higher in protected plotscompared with plots under cattle grazing. Suppression of anthropogenic degradation has resulted in higher adult tree density in protected plots, indirectly higher pollinator visitation to inflorescences and higher reproductive success of trees. Increased frequency of plant-pollinator interactions and tree reproduction suggest success ofmanagement practices aimed at protecting P. flexuosa woodlands.