The role of howler monkeys (Alouatta caraya) in the primary succession of the Parana flooded forest (Argentina)

In disturbed forests, Atelidae primates, such as howler monkeys, are known to play a key role in the dynamics of secondary succession. However, little is known about their role in primary succession. Thus, the aim of the present study was to evaluate the role of the howler monkey Alouatta caraya in the primary succession dynamics of the Parana flooded forest, in northeastern Argentina. This was achieved by studying the recruitment of saplings in the latrines of A. caraya groups inhabiting the forest in the first stages of succession and the distribution of plant species in relation to the age of the forest. The results showed that: (a) young forest areas were dominated by tree species dispersed by water, wind, birds, bats and fishes, whereas older forest areas were dominated by species dispersed by A. caraya, with individuals of some species present in young forests; (b) the floristic composition of saplings growing in A. caraya latrines of young forest areas was similar to that of old forest areas; and (c) saplings growing in young forest areas were heavily associated with A. caraya latrines and corresponded to species from older forest areas. The results allow the conclusion that A. caraya plays a role in the last phase of primary succession of the Parana flooded forest, as well as in contributing to an increase in the structural complexity and species diversity in the young areas of the Parana islands. Abstract in Spanish is available with online material.