Fruit-frugivore interactions are a vital ecological component of Amazon forest biodiversity and fruit-fall biomass data provide insight into the spatial heterogeneity of resources for terrestrial frugivores and other consumers. Here we describe, explain and predict meso-scale fruit-fall patterns within a lowland Amazon forest. Fruit-fall data were collected from May and June of 2016 with a ground survey in 90 plots (total of 4.42 ha) distributed across a 25 Km2 grid. Generalized additive models were used to explain and
predict the spatial patterns of fruit-fall dry biomass, richness and diversity. Multi model selection was used to determine the relative importance of space, topographic, hydrographic and vegetation cover. We counted 21812 fallen fruits, this total included fruits of 86 species from 28 families and 51 genera. Considering combined totals from both months, the mean fruit-fall biomass was 44.84 Kg ha-1 month-1 (±45.13 SD); mean number of species fruiting 4.3 (±2.6 SD) and mean Shannon diversity index 0.84 (±0.5 SD). We found that spatial effects most strongly explained variation in fruit-fall patterns and that the contribution of spatial, topographic, hydrographic and vegetation variables differed between responses of the variables. Whilst it was possible to explain substantial proportions of deviance in the responses, spatially explicit predictions using remotely sensed variables did not return accurate estimates. In an age of rapid adoption of remotely sensed data, our findings suggest that fruit-fall patterns are one of the myriad below canopy components of Amazon forest diversity that will continue to require ground based data collection. More sampling for space-time association is required
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