INVESTIGADORES
FARJI-BRENER Alejandro Gustavo
artículos
Título:
Leaf-cutting ant nests near roads increase fitness of exotic plant species in natural protected areas.
Autor/es:
FARJI-BRENER, AG; GHERMANDI, L
Revista:
PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON. SERIES B: BIOLOGICAL SCIENCES.
Editorial:
ROYAL SOC
Referencias:
Año: 2008 p. 1431 - 1440
ISSN:
0962-8452
Resumen:
Understanding the mechanisms that promote the invasion of natural protected areas by exotic plants is a central concern for ecology. We demonstrated that nests of the leaf-cutting ant, Acromyrmex lobicornis, near roadsides promote the abundance, growth and reproduction of two exotic plant species, Carduus nutans and Onopordum acanthium, in a national park in northern Patagonia, Argentina, and determine the mechanisms that produce these effects. Refuse dumps from ant nests have a higher nutrient content than nearby non-nest soils; foliar nutrient content and their 15N isotopic signature strongly suggest that plants reach and use these nutrients. Both species of exotic plants in refuse dumps were 50-600 % more abundant; seedlings had 100-1000% more foliar area and root and leaf biomass; and adult plants produced 100-300% more seeds than nearby non-nest soil plants. Plants can thus gain access to and benefit from the nutrient content of ant refuse dumps, supporting the hypotheses that enhanced resource availability promotes biological invasions. The two exotics produce an estimated of 8,385,000 more seeds /ha in areas with ant nests compared to areas without; this exceptional increase in seed production represents a potential threat to nearby non-invaded communities. We propose several management strategies to mitigate this threat. Removal efforts of exotics should be focused on ant refuse dumps, where plants are denser and represent a higher source of propagules.