Traditional home garden agroforestry systems: Habitat for conservation of baya weaver ploceus philippinus (Passeriformes: Ploceidae) in Assam, India

Abstract

The present study was conducted in 18 homegarden agroforestry systems of Assam to assess the role in the conservation of Baya Weaver Ploceus philippinus. Observations were made on the type of host trees, location of host trees, their spatial arrangement pattern, height and diameter of host trees chosen for nesting and the number of complete and helmet stage nests. Trail walks were employed for assessing the encounter rates of predators. A total of 2357 individuals of potential host trees for nesting of P. philippinus were found belonging to Areca catechu (2272), Cocos nucifera (56), Phoenix sylvasticus (13) and Borassus flabellifer (16). According to the spatial arrangement pattern of host trees, among 2272 individuals of A. catechu, 96.5% (n=2192) and 3.5% (n=80) of individuals were arranged in block and row pattern respectively. The other three host trees were arranged in single pattern. Among these 80 individuals of A. catechu planted in row pattern, 47.5% (n=38) had nests (complete and helmet stage) on them. In total, 293 nests (both complete and helmet stage) were observed in A. catechu, out of which, 46.1% (n=135) were complete nests. The other three host trees had nests in various stages of development but none of them were completed by P. philippinus. The encounter rates of predators (arboreal mammals) was significantly higher in block patterns (2.56 ± 0.51) as compared to row patterns (0.53 ± 0.17) of host tree spatial arrangement whereas, the encounter rates of reptiles showed no statistical difference among the two patterns of host tree arrangement. Thus, A. catechu planted in row pattern was the most preferred host tree species for nesting by P. philippinus as compared to the other three host tree species. The height and DBH of A. catechu trees having nests varied from seven to 11 m (7.8 ± 1.11) and 10.5-16.5 cm (12.6 ± 1.4) respectively. The homegarden agroforestry systems provided suitable habitat for survival of P. philippinus as this system has ample water sources, feeding grounds, nesting material and host tree sources and conservation attitudes of the homegarden owners, thus, suggesting that homegarden agroforestry system can be a potential site for conservation of P. philippinus in human-modified land use.