Redes de interações entre as comunidades de epífitas e de aves de Mata Atlântica na Reserva Ecológica do Guapiaçu, município de Cachoeiras de Macacu, RJ

Abstract

Epiphytes are present in 60% of tropical forests and act as diverse food resources that can be crucial in times of food scarcity. Their reproduction is supported by the avi-fauna, either through polarization or by fruits and seed dispersal, thus creating a vast interaction spectrum between both communities within a continuous ecological process. Few scientific studies concerning avian and epiphytic community interactions are available and not much is known on their specific relationships. However their absence can change existing ecological processes in the habitat. With this in mind, the research undertaken at Reserva Ecológica do Guapiaçu, Cachoeiras de Macacu, RJ, looked at analyzing bird and epiphytic interactions in three different environments; forest, fragmented forest and pastureland. The objective was to study how these habitats can vary according to their degree of conservation and successional stage. Three observation points were marked in three different forest fragments, twelve observation points were marked in a forest and ten observation points in the pastureland providing a total of 1344 observation hours. As a result, 643 avian and epiphytic community interactions were registered, many of them considered important to the maintenance of the existing communities in their habitat. The removal of material for nest building; the use of water for both bathing and drinking and the invertebrate fauna predation was clearly observed. The presented interaction networks covered the three environments and showed the value of 0.31, referring at his connectance.They were also calculated the bird selectivity, their degree of specialization and epiphyte availability. The initial hypothesis was that the largest number of registered interactions would occur in the preserved forest given its preserved state and existing biodiversity; however, surprisingly the pasture area presented the highest number and variety of interactions. This was followed by forest fragments and the forest though network connectivity was larger in the fragments substantiated by the few occurrences. Most of the birds observed in the different habitats presented a high interaction in pasture areas where resources and their availability are reduced, making epiphytes an important food supply, substantiated by the elevated number of occurrences. Epiphytes permit a valuable network of interactions by attracting a high diversity of birds especially those that disperse fruit illustrating their importance within a degraded environment.