CESIMAR - CENPAT   25625
CENTRO PARA EL ESTUDIO DE SISTEMAS MARINOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
The advantages of breeding in diverse habitats: Site-dependent effects of El Niño on foraging behaviour in Fiordland penguins/tawaki
Autor/es:
GARCIA BORBOROGLU, P.; ELLENBER, URSULA; SEDDON, PHIL; MATTERN, THOMAS; PUTZ, KLEMENS
Lugar:
Cape Town
Reunión:
Congreso; 9th International Penguin Congress; 2016
Resumen:
During the breeding season, penguins, like all central place foragers, have to balance the need for adequate breeding habitat with the requirement to find food to sustain themselves and their offspring. Some penguin species are confined to narrow distributional ranges for which they have adapted at times highly specialized foraging strategies. This, however, may render these species vulnerable to environmental perturbations that cause a spatial and temporal mismatch between food concentrations and penguin requirements. Fiordland penguins/tawaki (Eudyptes pachyrhynchus) breed only on a stretch of some 500 km of coast along New Zealand?s South Island. Yet, despite their limited distributional range the species inhabits remarkably diverse oceanic habitats, ranging from shallow coastal and continental shelf to pelagic and even Fiord ecosystems. This creates an interesting scenario where global environmental disruptions may affect parts of the population differently depending on which habitat the penguins utilize. As part of the 5-year ´Tawaki project¨ investigating for the first time the marine ecology of Fiordland penguins across their entire distributional range, we simultaneously studied their foraging ranges and diving behaviour at two sites, Jackson Head/West Coast and Milford Sound/Fiordland, when the events of the 2015 El Niño started to unfold. At Jackson Head, the effects of climate related disruptions at sea were dramatic as indicated by a high rate of starvation related chick mortality. GPS logger data revealed that in September 2015 female penguins, which are the sole provider of food in the first four weeks after chick hatching, travelled up to 100 km away from their breeding site, staying at sea for two or more days; contrasting with 2014where penguins had generally stayed within a 10 km radius from Jackson Head. At the same time, Fiordland penguins in Milford Sound experienced a successful breeding season seldom travelling further than a few kilometers from their breeding colony; no bird was found to forage outside the fjord. Diving data further showed substantial differences in foraging effort between both sites, with penguins from Jackson Head consistently diving to depths of 100 m or more, while their Fiordland counterparts mainly focused on shallower dives. Overall our data indicates that El Niño can have diametrically different effects on the marine habitats utilized by Fiordland penguins. It also highlights that habitat diversity needs to be taken into account when assessing the effects of climate related environmental change and perturbations.