The effects of fire on ant trophic assemblage and sex allocation
Caut, Stephane (Consejo Superior de Investigaciones Científicas (Espanya). Estación Biológica de Doñana)
Jowers, Michael J. (Consejo Superior de Investigaciones Científicas (Espanya). Estación Biológica de Doñana)
Arnan, Xavier (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Pearce-Duvet, Jessica (Consejo Superior de Investigaciones Científicas (Espanya). Estación Biológica de Doñana)
Rodrigo Domínguez, Anselm (Universitat Autònoma de Barcelona. Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia)
Cerdá, Xim (Consejo Superior de Investigaciones Científicas (Espanya). Estación Biológica de Doñana)
Boulay, Raphaël R. (Universidad de Granada. Departamento de Zoología)

Data:	2017
Resum:	Fire plays a key role in ecosystem dynamics worldwide, altering energy flows and species community structure and composition. However, the functional mechanisms underlying these effects are not well understood. Many ground-dwelling animal species can shelter themselves from exposure to heat and therefore rarely suffer direct mortality. However, fire-induced alterations to the environment may change a species' relative trophic level within a food web and its mode of foraging. We assessed how fire could affect ant resource utilization at different scales in a Mediterranean forest. First, we conducted isotopic analyses on entire ant species assemblages and their potential food resources, which included plants and other arthropods, in burned and unburned plots 1 year postfire. Second, we measured the production of males and females by nests of a fire-resilient species, Aphaenogaster gibbosa, and analyzed the differences in isotopic values among workers, males, and females to test whether fire constrained resource allocation. We found that, in spite of major modifications in biotic and abiotic conditions, fire had little impact on the relative trophic position of ant species. The studied assemblage was composed of species with a wide array of diets. They ranged from being mostly herbivorous to completely omnivorous, and a given species' trophic level was the same in burned and unburned plots. In A. gibbosa nests, sexuals had greater δ15N values than workers in both burned and unburned plots, which suggests that the former had a more protein-rich diet than the latter. Fire also appeared to have a major effect on A. gibbosa sex allocation: The proportion of nests that produced male brood was greater on burned zones, as was the mean number of males produced per nest with the same reproductive investment. Our results show that generalist ants with relatively broad diets maintained a constant trophic position, even following a major disturbance like fire. However, the dramatically reduced production of females on burned zones compared to unburned zones 1 year postfire may result in considerably reduced recruitment of new colonies in the mid to long term, which could yield genetic bottlenecks and founder effects. Our study paves the way for future functional analyses of fire-induced modifications in ant populations and communities.
Ajuts:	Ministerio de Ciencia e Innovación CGL2009-12472 Ministerio de Ciencia e Innovación CGL2009-09690 Ministerio de Ciencia e Innovación CSD2008-00040
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Ant assemblage ; Aphaenogaster gibbosa ; Reproductive output ; Sex ratio ; Stable isotopes ; Wildfire
Publicat a:	Ecology and evolution, Vol. 4, issue 1 (Jan. 2017) , p. 35-49, ISSN 2045-7758

DOI: 10.1002/ece3.714
PMID: 24455159

15 p, 1.7 MB

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