Bird Perches Increase Forest Seeds on Puerto Rican Landslides

Background

Forest regeneration is typically difficult after landslides due to loss of above- and below-ground vegetative structure, the soil seed bank, soil nutrients, and soil structure. Landslides are a common occurrence in Puerto Rico due to its steep topography and heavy rainfall periods and often transform into grass- or fern-dominated terrain. Insufficient seed rain is thought to be one contributing factor.

Research goals & methods

This study explores the effect on seed rain of installing bird perches on landslide-affected areas. Artificial bird perches replace the snags and living trees that are eliminated in landslides and increase seed rain on the disturbed areas. The study included six landslide areas including two fern-dominated areas; two grass-dominated areas; and two areas of bare soil. Seed baskets were placed underneath the bird perches to sample seed rain. Based on presence of fecal matter, seeds were classified as either bird-dispersed or wind-dispersed. Seedling establishment within the plots was also measured. Bird counts and visitation times were also captured.

Conclusions & Takeaways

Bird perches increase the abundance and diversity of seeds in landslide areas, especially seeds from interior forest areas. The effect was stronger in grass-covered areas as birds were also consuming grass seeds. While the study also found an increase in seedling establishment surrounding bird perches, the effects were non-uniform.