Consumidores de frutos de Persea lingue (Lauraceae) en el sur de Chile y su efecto en la germinación de semillas

Frugivory is a common interaction mechanism between plants and animals in the temperate rainforest of southernSouth America. In this study, we examined primary dispersal and predation stages of Persea lingue (Ruiz et Pav.) Nees(Lauraceae), an endemic large-seeded tree of these forests. The main goal was to determine the identity of vertebrate seeddispersers of P. lingue, to distinguish legitimate seed dispersers, pulp consumers and seed predators, and their influenceon seed germination. In order to know which birds and small mammals were feeding P. lingue seeds, we observed 20P. lingue canopies, and live traps baited with P. lingue seeds were installed in fragment forests in south-central Chile.To determine whether birds could be legitimate dispersers of P. lingue, we collected regurgitated and fecal samples. Weexamined whether rodents removed the fruit pulp, the seeds, or the whole fruit. Additionally, we studied if seeds placedon the forest floor were removed by rodents. In a final experiment we conducted germination trials to establish whetherpulp removal (by birds, rodents, or artificially-removed) influenced germination rates. We found six bird species feedingon P. lingue seeds. None of them defecated intact seeds, but, Turdus falcklandii Quoy & Gaimard (Turdinae) and Xolmispyrope (Kittlitz) (Tyrannidae) regurgitated intact seeds. We captured five species of rodents in Sherman traps. Four of themleft intact seeds. We did not find any effect of the seed handling types (pulp consumption vs. seed regurgitation) in seedgermination rates. However, pulp removal was an important factor for germination success. We conclude that T. falcklandiiand X. pyrope are legitimate seed dispersers of P. lingue, since they swallow the whole fruit and regurgitate the intactseed. Abrothrix olivaceus (Waterhouse) (Cricetidae) and probably Oligoryzomys longicaudatus (Bennett) (Cricetidae) arepotential secondary dispersers of P. lingue seeds, as they prefer to eat the fruit pulp rather than the seeds.La dispersión de semillas por endozoocoría es uno de los principales mecanismos de interacción mutualista entre plantas yanimales en el bosque templado de Sudamérica. En este estudio indagamos acerca de los mecanismos de dispersión primariay estadios de depredación de semillas de Persea lingue (Ruiz et Pav.) Nees (Lauraceae), árbol endémico de estos bosques.El objetivo principal fue determinar la identidad de los vertebrados dispersores de semillas de P. lingue, distinguiendodispersores legítimos, de consumidores de pulpa y predadores de semillas, y determinar su efecto en la germinación. Serealizaron observaciones focales de la copa de adultos de P. lingue; además, se instalaron trampas Sherman cebadas confrutos de P. lingue en fragmentos de bosque en el valle central del centro-sur de Chile. Se colectaron muestras de fecasy semillas regurgitadas, se determinó cuáles especies de roedores consumieron la pulpa, las semillas o los frutos enterosen las trampas. Se examinó si hubo remoción de frutos y semillas desde el suelo. Se realizó un ensayo de germinaciónpara determinar si la forma de la remoción de la pulpa afecta las tasas de germinación. Registramos seis especies de avesconsumiendo frutos, ninguna defecó semillas, Turdus falcklandii Quoy & Gaimard (Turdinae) y Xolmis pyrope (Kittlitz)(Tyrannidae) regurgitaron semillas intactas. Capturamos cinco especies de roedores en las trampas, cuatro dejaron semillasintactas. No encontramos efecto del tipo de manipulación de las semillas en su germinación. La remoción de la pulpa fuedeterminante para el éxito de germinación. Concluimos que T. falcklandii y X. pyrope son dispersores legítimos de semillasde P. lingue. Abrothrix olivaceus (Waterhouse) (Cricetidae) y probablemente Oligoryzomys longicaudatus (Bennett)(Cricetidae) son potenciales dispersores secundarios, dada su marcada preferencia por la pulpa sobre las semillas

Frugivory on Persea lingue in temperate Chilean forests: interactions between fruit availability and habitat fragmentation across multiple spatial scales

Habitat degradation and fragmentation are expected to reduce seed dispersal rates by reducing fruit availability as well as the movement and abundance of frugivores. These deleterious impacts may also interact with each other at different spatial scales, leading to nonlinear effects of fruit abundance on seed dispersal. In this study we assessed whether the degradation and fragmentation of southern Chilean forests had the potential to restrict seed dispersal the lingue (Persea lingue) tree, a fleshy-fruited tree species. Of five frugivore bird species, the austral thrush (Turdus falcklandii) and the fire-eyed diucon (Xolmis pyrope) were the only legitimate seed dispersers as well as being the most abundant species visiting lingue trees. The results showed little or no direct effect of habitat fragmentation on seed dispersal estimates, possibly because the assemblage of frugivore birds was comprised habitat-generalist species. Instead, the number of fruits removed per focal tree exhibited an enhanced response to crop size, but only in the more connected fragments. In the fruitricher fragment networks, there was an increased fragmentsize eVect on the proportion of fruits removed in comparison to fruit-poor networks in which the fragment size eVect was spurious. We suggest that such nonlinear eVects are widespread in fragmented forest regions, resulting from the link between the spatial scales over which frugivores sample resources and the spatial heterogeneity in fruiting resources caused by habitat fragmentation and degradatio