INVESTIGADORES
ARETA Juan Ignacio
congresos y reuniones científicas
Título:
Bamboo specialist birds of the Neotropics: focus on the Atlantic forest, a hotspot for bamboo specialists
Autor/es:
ARETA JI; COCKLE K
Lugar:
Campos do Jordão
Reunión:
Simposio; 25th International Ornithological Congress; 2010
Resumen:
Although bamboos occur in many regions, most birds that
specialize on bamboo seem to occur in the Neotropics. Specialization on bamboo
seeds, shoots and insects, has arisen in at least 15 families of Neotropical
birds. The Atlantic forest region is a hotspot for bamboo specialist birds,
with 13 species occurring in the Atlantic forest of Argentina. We predict
the abundance and distribution of these species to vary quasi-cyclically over
time, in response to the availability of their preferred bamboo resources,
which depend on the deep-time dynamics of changing bamboo flowering overlap.
Specialists on seeds of Guadua, like
Temmincks seedeater (Sporophila
falcirostris), which has the lower mandible much thicker than the upper
mandible, occur in Argentina
every ~15 years when one of the two Guadua
seeds. The uniform finch (Haplospiza
unicolor) with a thinner, conical bill, also exploits Guadua seeds but has a broader niche, feeding primarily on Chusquea ramosissima seeds, which are
always available somewhere in the region. The blackish-blue seedeater (Amaurospiza moesta) apparently feeds
primarily on green bamboo matter, and secondarily upon seeds, especially in Merostachys bamboo; we do not expect
large population fluctuations. The white-bearded antshrike (Biatas nigropectus) is an insectivore
almost always found in Guadua trinii;
we predict its populations to increase over the vegetative phase of G. trinii, but decline sharply when it
dies after flowering en masse. The most specialized bamboo-users like S. falcirostris, B. nigropectus and the purple-winged ground dove (Claravis godefrida) should experience
the largest population fluctuations and be the most vulnerable to stochastic
extinction.