Latitude, altitude on body size variation in Andean passerine birds.
BLACKBURN, TIM M.; RUGGIERO, ADRIANA
GLOBAL ECOLOGY AND BIOGEOGRAPHY
Lugar: Oxford; Año: 2001 vol. 10 p. 245 - 259
ABSTRACT1.-Relationships between body mass and latitude,and body mass and elevation are examined in theassemblage of Andean passerine birds.2.-Across species, body mass is positively correlatedwith the mid-point of the species elevationaldistribution, but there is no significant relationshipbetween body mass and latitudinal range mid-point.3.-When the assemblage is separated into Andeanendemic and non-endemic species, the former groupshows a significant positive relationship betweenbody mass and elevation, and the latter a significantpositive relationship between body mass andlatitude (Bergmanns rule). Andean endemicspecies exhibit Bergmanns rule once elevation iscontrolled for using multiple regression.4.-These relationships are not a consequence ofthe phylogenetic non-independence of species. Allthe effects shown are very weak, with latitude andelevation explaining only a few per cent of thevariation in body mass. Relationships are strongestwhen phylogenetically controlled analyses areperformed just within genera.5.-The implications of these results for the mechanisticunderstanding of Bergmanns rule arediscussed.