INVESTIGADORES
YORIO Pablo Martin
congresos y reuniones científicas
Título:
Trophic resource partitioning among terns in different species coexisting contexts: an integrated classical and isotopic niche approach
Autor/es:
GATTO, A.; YORIO, P.
Lugar:
Victoria
Reunión:
Congreso; First World Seabird Conference; 2010
Resumen:
The trophic ecology of South
American (Sterna hirundinacea), Cayenne (Thalasseus
sandvicensis eurygnathus) and Royal (Thalasseus
maximus) terns was evaluated at the colonies of Punta León (43ºS) and Punta
Loma (42°S), Patagonia, Argentina. Cayenne terns bred with the larger Royal
terns in the former and with the smaller South American terns in the latter. The
diet and use of marine areas were evaluated by means of prey delivery
observation, radiotelemetry and stable isotope analysis. Data were then compared
and integrated to evaluate the potential differences in their use of trophic
resources. At each colony, the larger tern species showed a higher prey
specialization, included a larger proportion of the prey with higher energetic
content (Engraulis anchoita), and
showed a higher trophic level than the smaller one. The larger tern species in
both colonies preyed upon larger fish than the smaller one. Telemetry data
suggest that tern species have a similar use of foraging areas, but differ in
their temporal foraging patterns. Royal and Cayenne terns at Punta León showed higher
amplitude in the isotopic niche in relation to the trophic level of their prey,
but a relatively low amplitude in the use of the marine space. In contrast, Cayenne and South
American terns at Punta Loma showed higher amplitude in the use of the marine
space and relatively low amplitude in relation to prey trophic level. Results
suggest that tern species differ in their trophic resource utilization, and that
those differences are dependent on the combination of coexisting tern species.