Abstract

Little has been published on a small-scale (x < 100 ha) about the independent impact of the shape and size of fragments on community structure of any biological group. Only studies in large scale, in temperate ecosystems, have been performed. Here, the bird community structure was assessed in small High-Andean tropical forest fragments (x < 100 ha). Through direct observation using belt transects we compare bird composition, density, richness and diversity between fragments of three different sizes (10.1 ha < x < 100 ha, 1.1 ha < x < 10 ha and x < 1 ha) and two shapes (polygonal and elliptical). We found that density values differed significatively when comparing shape and size, been higher in smaller and elliptical fragments. Bird richness, Shannon, Fisher-alpha and dominance indexes differed regarding size but not fragment shape. Bird composition changed with fragment shape but not with size. The results coincide with studies conducted in larger fragments (over 1000 ha) in which, bird community composition, density and diversity may be responding to both, fragment shape and size. This emerging pattern observed for birds in the High-Andean forest at small scale should be confirmed experimentally as well as replied in other biological groups and tropical ecosystems. Keywords: Fragmentation; shape; size; assemblage; bird communities; urban ecosystem; High-Andean forest; Colombia.