Effect of drought and megafire in Iberá National Park, Corrientes, on the reproduction of the Iberá seedeater Sporophila iberaensis

JUAN FRANCISCO CATAUDELA; MELANIE BROWNE; MARIO S. DI BITETTI; ADRIAN S. DI GIACOMO

Gramado

Congreso; II Ornithological Congress of the Americas; 2023

Northeastern Argentina Grasslands have been identified as a biodiversity conservation priority environmentparticularly for endangered grassland birds. The Iberá Seedeater Sporophila iberaensis, is a migratory bird,categorized as Endangered by IUCN, endemic to South American flooded grasslands with a restricted distribution.Its only reported breeding site is found within the Iberá wetlands. The main objective of this study was to evaluatethe impact that extreme climatic conditions, such as severe droughts and megafires that took place in Corrientesprovince in early 2022, had on the reproduction of S. iberaensis. We have evaluated its main breeding parametersand compared 73 nest attempts during 2022 (drought & post-fire. n=35) and 2018 (normal rains & pre-fire, n=38)breeding seasons. The principal cause of nest failure was predation (55%) and storm-associated falls (12%). We didnot find significant differences in daily survival rate, in clutch size, nor in hatching success between years. However,we found differences in predation rate, being lower during the dry season compared to the humid season, with nestpredation probabilities of 56% and 79%, respectively. Our results suggest that S. iberaensis reproduction waspositively affected during the 2022 breeding season with dry and post-fire conditions. These results may have beeninfluenced by a diminution in mortality after fire/drought generated by changes in the mesopredator ensemble ordue to a potential increase in food availability for the species as a consequence of the regrowth of vegetation afterthe megafire.