Disponibilidade e consumo de frutos de Michelia champaca L. (Magnoliaceae) na área urbana de Uberlândia, MG: uma interação ave-planta exótica

Abstract

Exotic plants used in urban tree planting can play an important role in bird conservation in urban environments when they offer some kind of resource. The aim of this study was to evaluate the availability of fruits of Michelia champaca in the urban area of Uberlândia, and its consumption by birds. Three green areas of the city were selected: Parque do Sabiá, Praça Montese and Campus Umuarama of Federal University of Uberlândia. The study was carried out between June 2008 and October 2009. Observations were made with the aid of binoculars (8x40mm) for the analysis of consumption of diaspores (arillate seeds) by birds between 06:00 and 18:00 h (2 to 4 hours sessions). 167 hours of observation were accumulated, 47 in Parque do Sabiá, 51 in Campus Umuarama and 69 in Praça Montese. The availability of diaspores was estimated by counting all visible open fruits in 9 individuals on Campus, 13 on Praça and 12 on Parque. Mature fruits were available in at least one of the areas along virtually the entire period of study even in months of dry season, with the most abundant fruiting occurring in February 2009. A total of 149 feeding events (FE) performed by 20 species of birds (3 orders, 6 families, 15 genera) were recorded. The most frequent species were Dacnis cayana and Tersina viridis with 29 (19.5%) and 21 (14.1%) FE, respectively. These two species were also those who consumed the highest number of diaspores, with 54 (20.3%) being consumed by T. viridis and 43 (16.17%) by D. cayana. Of all consumed diaspores, 85.3% (n = 227) were collected by perching birds and 14.7% (n = 39) were collected in flight. The most frequent feeding behaviour was swallow diaspore immediately (n=149; 56.02). The higher mean of FE was between 8:00 and 9:00 h ( X = 1.5 ± 1.47) followed by the period of 7:00 to 8:00 h ( X = 1.46 ± 1.41). There was no significant difference between areas in the number of diaspores consumed (Kruskal-Wallis; H=4.33; gl=2; p=0.12).The number of feeding events presented marginally significant diference between areas (Kruskal-Wallis; H=5.83; gl=2; p=0.055). Comparing the number of FE of the main consumers there were significant difference between areas (Kruskal- Wallis; H= 10.45; gl=2; p=0.005). Regarding the composition of avifauna, the cluster analysis revealed a greater similarity between Praça Montese and Campus Umuarama (CS = 0.69). Regarding to feeding habits, there was a predominance of omnivores (n = 13; 65%), followed by insectivorous species (n = 6; 35%). There were no records of agonistic interactions among consumers of M. champaca. The results suggest that this species can act as an alternative source of alimentary resources for the local avifauna, since its fruits are available during most of the year.