Predicting forest management effects on oak-rodent mutualisms

MORÁN-LÓPEZ, T.; WIEGAND, T.; MORALES, JUAN M.; VALLADARES, F.; DÍAZ, M.

OIKOS

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2016 vol. 125 p. 1445 - 1457

0030-1299

Wood mice Apodemus sylvaticus are the main dispersers of acorns in highly managed Mediterranean holm-oak woodlands. Mice mobilize and cache acorns to store them for winter consumption. ey carry acorns away from potential competitors, face predation risks during mobilization, and cache acorns in areas where pilfering risks are low. However, mice can act either as net predators or as moderately e cient dispersers, depending on the way landscape management a ects intraspeci c competition for acorns and shelter availability. To assess the in uence of landscape structure and mouse behavior on acorn dispersal, we developed an agent-based model (ABM) that translates forest management into changes in key environmental factors driving mouse foraging decisions. e model was able to predict accurately acorn dispersal patterns in a wide range of forest management practices based on information on forest habitat availability, stem density and shrub cover. Sensitivity analysis revealed that caching rates emerged from the interplay between intraspeci c competition for seeds and predation risk accepted during mobilization. It also showed that intraspeci c competition for acorns decreased with increasing habitat loss (due to positive edge e ects on acorn production) while landscape resistance to mouse movements increased. As a result, the net bene ts of caching declined and acorn predation became the dominant strategy. Finally, we assessed the e ects of shrub encroachment as a management practice to enhance dispersal services in savanna-like landscapes (dehesas). e model predicted non-linear responses with a 65% threshold of shrub cover needed to achieve relatively high levels of acorn dispersal. is value may not be compatible with the traditional exploitation of dehesas (livestock rearing). Our study shows that integrated approaches that combine environmental change driven by management with behavioral responses of dispersers improve our under- standing of the causes of recruitment bottlenecks, and are useful tools for evaluating conservation strategies aimed at enhancing dispersal services.