Darocha et al. 2016 (Article) Brazil

Epiphytic bromeliads as key components for maintenance of ant diversity and ant–bromeliad interactions in agroforestry system canopies

Author(s):—W.D. Darocha, F.S. Neves, W. Dáttilo & J.H. Delabie

Publication:—Forest Ecology and Management 372: 128-136. (2016) — DOI

Abstract:—Cocoa is produced in a wide range of land use systems, with the traditional shaded systems in Bahia (Brazil) as the most forest-like and biodiverse. The aim of this study was to evaluate the role of different cocoa agroforestry systems (AFSs) in maintaining community structure and interactions between ants and epiphytic bromeliads. The study was conducted at four sites in the cocoa producing region of the southeastern of the state of Bahia, Brazil, and comprised a native forest and three different cocoa AFSs. We found a total of 103 ant species associated with epiphytic bromeliads, with 83% of the species occurring in native forest canopy bromeliads also occurring in cocoa AFSs. The Cocoa Cabruca System (CAB) and the Rustic-Planted Shade System (RPS) had ant community structural components of biodiversity similar to those found in the native forest environment. The alpha and gamma diversity of ants found in Monospecific-Shaded Cocoa Agroforestry System (MCA) associated with Erythrina spp. shade trees were significantly different from the diversity found in the other AFSs and native forest. The presence of epiphytic bromeliads, regardless of the system and scale, maintained ant diversity in agroforestry system canopies similar to that of native forest. Using metrics derived from graph theory, we found a high level of specialization regarding ant–bromeliad interactions in native forest, with a gradual decrease in specialization with environmental homogenization. Agroforestry systems thus represent an important strategy for maintaining the structure of canopy-associated ant communities by enabling the establishment of numerous bromeliad species, thus contributing to the maintenance of ant diversity and services in a mosaic landscape AFSs and native forest.

Keywords:—Tropical forests, Ecological networks, Beta diversity, Tank bromeliads, Formicidae