Seed rain and seed limitation in a planted gallery forest in Brazil

Background

Seed dispersal by wind (anemochorous) and animals, usually birds and bats (zoochorous), is an important driver of succession. This study examines seed rain in a planted gallery forest (riparian corridor) in Brazil.

Research goals & methods

The gallery forest had been planted in 1994, a diverse mixture of 40 species in a narrow corridor no wider than 50m planted along 12ha of riverbank previously subject to rice and sugar plantations. Forest fragments were present between 500m to 8km away. Ten years after establishment, 60 seed traps were placed below individuals of the four most common planted species in the gallery and monitored monthly over the course of one year. Conspecific seeds were eliminated from the analysis to avoid counting undispersed seeds. 62% of seeds were considered undispersed. Seeds of pioneer species predominated in the seed rain. 22 of the collected seed species came from those that had been planted in the gallery representing 43% of the sample, while 9 came from species that had colonized the area.

Conclusions & takeaways

Overall (anemochorous and zoochorous) seed rain was not influenced by distance to the gallery border or vegetation characteristics in the immediate vicinity of the seed trap. However, the abundance and richness of animal-dispersed seeds in a given location was influenced by the abundance and richness of zoochorous plants in the immediate vicinity. Some limitation on dispersal existed; for 18 of 31 collected seed species, >80% of traps failed to receive any seed.