Seed dispersal networks and functional diversity; 2010-2011; Bolivia

We carried out this study in a tropical mountain forest in the Bolivian Andes nearby the town of Chulumani from June 2010 to February 2012. We recorded plant-frugivore interactions at eight study sites with a standardized sampling design, encompassing a total of 768 hours of observations. At every site, we established two 20 x 100 m² plots parallel to the forest margin (i.e. the border between the forest remnant and the deforested matrix): 1) one at the forest edge, 10 m from the forest margin, and 2) another in the forest interior, 160 m from the forest margin. In each plot, we recorded all bird species that fed on fleshy fruits during four observation sessions conducted during two dry seasons (2010-2011) and two wet seasons (2011-2012). For each frugivorous species, we recorded data for three functional traits: (1) body mass, (2) length of wing tip and (3) gape width. Body mass was derived from Dunning (2007). We estimated the crop size of individual trees by counting the number of all fruits on at least five branches to obtain the average number of fruits per branch and multiplied this with the total number of branches with fruits in the tree. Finally, to measure the seed deposition pattern we installed eight seed traps per plot, located along transects of 20 m length parallel to the forest margin.