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Bird-mediated effect of deforestation on potential seed dispersal does not increase the seed recruitment of Fuchsia magellanica

Morales-Paredes, Carlos, Valdivia, CarlosE., Orellana, JoséI.
Trees 2018 v.32 no.1 pp. 245-254
Fuchsia magellanica, birds, color, deforestation, dough, forests, frugivores, fruits, habitat destruction, lizards, mature plants, models, pioneer species, seed dispersal, seedlings, seeds, shrubs, species recruitment, sugars
KEY MESSAGE: This work contributes to clarify the effects of small-scaled deforestation and key traits of plants and animals on frugivory, seed dispersal and seedling recruitment of a shade-intolerant plant. Habitat destruction usually reduces the frugivory and seed dispersal by animals. This negative effect could be counterbalanced by seedling recruitment in shade-intolerant plants. We tested this assumption using the shrub Fuchsia magellanica as a model. We estimated the deforestation as the percentage of ground surface devoid of native forest at small and large scales around 20 plants per population and 12 populations. This procedure was performed to evaluate the effects of deforestation, at both spatial scales, on fruit traits, frugivory, seed dispersal, and seedling recruitment. Fruit traits (size, shape, color, sugar concentration, and number of seeds) were measured in each plant. Frugivory by lizards and birds were recorded as the percentage of fruit consumed, using ten artificial play dough fruits per plant. Putative seed dispersal was estimated as the product of the number of play dough fruits attacked and mean number of seeds per fruit. Seedling recruitment was evaluated as the density of seedlings growing around adult plants. The fruit traits of F. magellanica varied among populations in size, shape, color, sugar concentration and number of seeds. Only color correlated with deforestation at a large scale, the fruits being more reddish-brown in deforested populations. This variation, however, did not affect frugivory. The number of play dough fruits attacked by birds exhibited a tendency to be positively affected by deforestation at a large scale, which could be translated into a positive effect of deforestation on potential seed dispersal. Nevertheless, there was not an increase in seedlings recruitment. Consequently, the deforestation did not increase the seedling recruitment of this pioneer species.