The influence of the succession gradient and Merostachys aff. multiramea fruiting in a community of birds in the Araucaria Forest

ABSTRACT

The Mixed Rain Forest (Araucaria Forest) is currently restricted to less than 1% of the original area, occurring in different succession stages and degrees of preservation. This paper presents the influence of the gradient of succession vegetation and the phenomenon of bamboo (Merostachys aff. multiramea) flowering and fruiting on a bird community in an area of ​​Araucaria forest on Santa Catarina. Between 2009 and 2010, 20 monthly samples were performed using the methodology of capturing and marking using mist-nets in three successional stages (initial, intermediate and advanced). During sampling, the fruiting of bamboos began in January 2010, allowing an equivalent sampling before and after the event. A total of 557 individuals belonging to 77 species were captured. The highest relative abundances occurred to Haplospiza unicolor (AR = 20,80%), due to the relationship of this species with bamboos in flowering. The highest relative abundance ocurred for 58,44% of the species, pattern already reported in studies using mist-nets in neotropical forests. The highest diversity was found in the initial stage (H'=3,45), followed by intermediate and advanced sucessional stages. However, the equitability is more pronounced in the intermediate stage. The Jaccard similarity index showed that the initial stage is the most different in their composition avifauna in relation with others. The results also showed that the opening of gaps due to the death of bamboos after flowering has a similar role that occurring with habitat fragmentation, with specific impacts in understory insectivores and understory omnivores.

KEYWORDS
Avifauna; Mixed Rain Forest; bamboos; forest succession