Earthworm taxonomic structure of coffee plantations at three soil associations in Puerto Rico

Abstract

The taxonomic structure of earthworms of coffee plantations systems at three different places in Puerto Rico (Las Marías, Lares, and Jayuya), representing different soil types, was assessed. Organisms were manually sorted in a 0.25 m², and various soil analyses were carried out. Eight earthworm species were identified: Onychochaeta borincana, Pontoscolex corethrurus, P. melissae, P. spiralis, and Pontoscolex sp., which belong to the Glossocolecidae family, and Amynthas gracilis, A. rodericensis, and a pheretimoid species which belong to the Megascolecidae family. Some significant differences among soil properties were found between locations, treatments, and the interaction effects, but no clear patterns between these differences accounted for the taxonomic structure and abundance of earthworms at these coffee plantations. Higher abundances of exotic species were found in the most distressed areas as expected. P. corethrurus was found at all the investigated coffee plantations. Lares, the second area of highest elevation, had the higher density of earthworms. On the other hand, Jayuya, the most isolated area, had the highest species number. P. melissae, a rare species that had been reported from only three locations in Puerto Rico when it was described in 1991, was found only in Jayuya.

Key words:

• Earthworms
• coffee plantations
• Puerto Rico