Effect of canopy opening in Nothofagus antarctica forest bird assemblage of Tierra del Fuego with livestock use.

BLAZINA ANA PAULA; PERI PABLO LUIS; BENITEZ JULIETA; LENCINAS MARÍA VANESSA

Villa La Angostura

Congreso; IV Congreso Nacional de Sistemas Silvopastoriles; 2019

INTA

Birds are considered good indicators of ecological change. The livestock use and the silvopastoral proposals in Nothofagus antarctica (ñire) forests in Tierra del Fuego, involve the opening of its canopy, causing changes in its avifauna that have not been yet studied in detail. In this work, differences were analyzed in the structure and composition of terrestrial bird communities in N. antarctica forests with integrated livestock along a canopy opening gradient, in Tierra del Fuego, Argentina. The analyzed forest types were: very closed (87% canopy cover-CC, 38 m2 basal area-BA), closed (71% CC, 37 m2 BA), open (61% CC, 39 m2 BA) and very open (21% CC; 1 m2 BA), existing in all disetaneity. Four replicas were selected of each forest type, revisiting them three times monthly in January and February 2017 and 2018. The variation in specific richness, density, Shannon-Wiener diversity, and percentage of trophic guilds in general and by substrate (soil, tree and air) were analysed between forest types. We recorded 20 species in total, presenting greater richness and lower density in more open forests (p < 0.01 in the two), while diversity did not vary between treatments (p = 0.96). The carnivorous guild increased with the canopy opening, while all guilds modified the use of substrates (eg., insectivores used more soil in more closed forests). The canopy opening generates changes in the richness and the density of individuals of assemblage of bird ensamblage, in the carnivorous guild and in the use of substrates, aspects that should be considered for their conservation in managed forests of N. antarctica with integrated livestock.