Frugivory by birds in four species of Cactaceae in the Caatinga, a dry forest in Brazil

ABSTRACT Birds are known to play an important role in the reproduction of various species of plants through frugivory and seed dispersal. Despite the importance of cactuses in seasonal environments, few studies have evaluated interactions between frugivorous birds and these plants. The present study aimed to identify the species of birds that feed on the fruits of Cereus jamacaru D. C. (1828), Pilosocereus gounellei (F. A. C. Weber) Byles & G. D. Rowley (1957) subsp. gounellei, Pilosocereus pachycladus (F. Ritter), Kakteen Südamerika (1979) and Pilosocereus tuberculatus (Werderm.) Byles & Rowley (1957), and to estimate their potential as seed dispersers. The study was carried out in the Catimbau National Park, located in the semiarid region of state of Pernambuco, between February 2017 and August 2017. In 78 hours of focal observation on plants, 20 species of birds belonging to 11 families were recorded consuming parts of the pulp of the four species of cactuse. The composition of visiting birds varied according to the species of cactuse. The species of birds considered potential seed dispersers were Tachyphonus rufus (Boddaert, 1783), Tangara sayaca (Linnaeus, 1766), Paroaria dominicana (Linnaeus, 1758) and Mimus saturninus (Lichtenstein, 1823). Pilosocereus tuberculatus was visited by a single bird species, Forpus xanthopterygius (Spix, 1824). This is the first study to identify birds as frugivores and potential seed dispersers of P. pachycladus and P. tuberculatus. Additionally, our study indicates that frugivorous and omnivorous birds are the main potential seed dispersers of C. jamacaru, P. pachycladus and P. gounellei subsp. gounellei.