Estrutura das redes de interação beija-flor e planta nos diferentes domínios fitogeográficos brasileiros

Abstract

Hummingbirds play an important role in the pollination of many plant species and are numerically and ecologically dominant in bird-plant interactions in the New World, representing the largest group of vertebrate pollinators in the Neotropical region. Using a database, we evaluated the structure of hummingbird-plant interaction networks by defining the specialization and centrality of component species, the similarity in species composition and the morphological attributes of plants and hummingbirds in five Brazilian vegetation domains. In order to evaluate the structure of interaction networks, 35 weighted matrices were created, representing interactions recorded in the Atlantic Forest, Cerrado, Caatinga, Pantanal and Pampa domains. The networks were evaluated separately and the following indices were calculated that describe their structure: connectance (C), specialization (H2'), modularity (M) and nesting (NODF2). In total, visits by 41 species of hummingbirds to 553 species of plants were recorded. The metrics that describe the structure of interaction networks did not differ significantly between domains, despite there being great variation in the composition of plant species between them. Connectivity and Modularity were low, while Specialization (H2') and Nesting were moderate in all domains. Interactions were more specialized in Atlantic Forest networks, given the higher values ​​of specific specialization (d’) and greater length of the flower corolla in this domain. We suggest more detailed studies evaluating the morphological adjustment between hummingbirds and flowers across domains, and how the specialization of these species is affected by these attributes.