Fruit-eating birds in experimental plantings in southern Mexico

Maintenance of biodiversity in tropical agrarian landscapes is challenging in the face of anthropomorphic simplification of habitats. As part of an experiment testing influences of planting treatment on tree recruitment in southern Mexico, counts of bird species were made over 10 years in 24 30 × 30-m fenced plots in over-grazed pasture. Plots were planted with native tree species or left as unplanted controls in 2006. Annual censuses of birds in the plots from 2007-2016 indicated satistically significant increases in the number of fruit-eating species and individuals as vegetation matured, but increases in non-frugivorous species and individuals over the decade were not significant. Among four species of planted animal-dispersed trees that bore fruit during this time, Cecropia obtusifolia consistently produced substantial crops after 2009. In 2015, all 53 planted or passively-recruited female trees of mature size of this species bore fruit. The summed body masses of fruit-eating birds in each of 24 plots were significantly correlated with rank order of available fruit per plot. Differential use of habitat patches in an agrarian landscape suggested substantial value to frugivores, but less to non-frugivorous birds than expected.