Beyond predator satiation : masting but also the effects of rainfall stochasticity on weevils drive acorn predation
Espelta Morral, Josep Maria (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Arias-LeClaire, Harold (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Fernández-Martínez, Marcos (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Doblas Miranda, Enrique (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Muñoz, Alberto (Universidad Complutense de Madrid. Departamento de Didáctica de las Ciencias Experimentales, Sociales y Matemáticas)
Bonal, Raul (Instituto de Investigación de la Dehesa)

Fecha:	2017
Resumen:	Escaping seed predation is a classic "economy of scale" hypotheses (predator satiation hypothesis, Psh) to explain the selection for the synchronous production of massive and nil seed crops (masting) in plants. The Psh postulates that predator satiation occurs through a combination of (1) "functional satiation," as not all seeds can be consumed during a massive crop, and (2) "numerical satiation," as predator populations collapse during poor crop years. Many studies advocate for the Psh, but few have investigated the importance of masting compared to other factors for the control of predation extent. Namely, environmental cues prompting masting could also determine predator's success and, ultimately, influence directly and independently seed predation intensity. We explored this question in Mediterranean oaks, as they exhibit strong masting behavior; acorns are heavily predated upon by weevils; and rainfall stochasticity drives masting and the emergence of adult weevils from the soil. Results of two mid-term studies (4 and 11 yr) showed that acorn production and predation were highly variable across years, while the abundance of adult weevils was positively related to autumn rainfall and to the number of infested acorns the previous years. Ultimately, acorn predation was negatively influenced by inter-annual fluctuation of seed production (masting) yet, mainly and positively, prompted by autumn rainfall and acorn crop size (only in one site). Our results highlight the relevance of masting to reduce seed predation. Yet evidences that rainfall stochasticity directly determines the success of weevils, and it independently influences seed predation extent, indicate that environmental cues prompting masting may also fine-tune the output of this reproductive behavior. Additionally, local differences suggest that the relevance of masting may change with tree characteristics (low vs. high seed production) and landscape structure (isolated vs. dense forests). We also discuss what can be the effects of increasing drought in Mediterranean areas for this antagonistic interaction, triggered by rainfall.
Ayudas:	Ministerio de Economía y Competitividad CGL2015-70558-P Ministerio de Economía y Competitividad AGL2014-54739-R Ministerio de Economía y Competitividad CGL2012-33398 Ministerio de Ciencia e Innovación CSD2008-00040 Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-913 Agència de Gestió d'Ajuts Universitaris i de Recerca FI-DGR 2013
Derechos:	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.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió publicada
Materia:	Curculiospp ; Extended diapause ; Granivory ; Mediterranean oak forests ; Plant-animal interactions ; Pre-dispersal seed predation ; Quercus ilex ; Resource pulses
Publicado en:	Ecosphere, Vol. 8, issue 6 (June 2017) , e01836, ISSN 2150-8925

DOI: 10.1002/ecs2.1836

13 p, 582.3 KB

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