Quantity component of the effectiveness of seed dispersal by birds in the temperate rainforest of Chiloé, Chile

Abstract

The quantity component of the disperser effectiveness of resident birds during the autumn-winter period has not yet been detailed in temperate rainforests of South America. In this study, the potentially frugivorous bird species in the temperate rainforests of southern Chile during the Austral autumn-winter were identified, and the quantity component of the disperser effectiveness of the birds (number of visits and number of seeds dispersed per hour) were evaluated for the tree species Luma apiculata and Aextoxicon punctatum. During the peak fruiting period of the both L. apiculata and A. punctatum 10 and 14, respectively, individuals of each species were monitored for a total of 10 days. Results show that four bird species consumed L. apiculata fruits. The birds Turdus falcklandii were the main fruit consumers (72 % of the visits), with a mean rate of 2.2 visits per hour and 49.2 seeds dispersed per hour. The frugivorous species visiting A. punctatum were T. falcklandii (97 % of the visits) and Columba araucana (3 %). In A. punctatum, T. falcklandii consumed 65 fruits in 35 visits, with a mean rate of 1.8 visits per hour and 3.4 seeds dispersed per hour. In conclusion, T. falcklandii would be the most effective seed disperser bird for autumn-winter fruiting trees in the Chiloé rainforest of our study site, at least with regard to the quantitative component of disperser effectiveness.