CONSERVATION OF THE ORINOCO GOOSE (NEOCHEN JUBATA) IN THE MIDDLE ARAGUAIA RIVER, TOCANTINS, BRAZIL.

Abstract

The Orinoco goose, (Neochen jubata) is a grazing herbivore of open habitats that was once widely distributed in tropical South America. Centuries of overhunting and habitat loss have reduced it to widely scattered remnant populations; it is categorized as Near Threatened globally. Within the Cerrado biome, the Middle Araguaia River houses the largest remnant population. In August 2017, a study was started to assess the situation of the Orinoco Goose in the regions of Araguaia National Park, Cantão State Park, and adjacent rice fields. We conducted counts from an aerial census (a 700 km transect), monthly boat censuses (40 km) and land censuses in rice plantations. The aircraft census counted 367 individuals in August 2017, while monthly monitoring of a stretch of the lower Javaés River over more than two years showed a seasonal population variation associated with the flood regime, with the species virtually disappearing during the flood period between January and April when river beaches are submerged. During this period, large flocks of about 1,000 Orinoco Geese were discovered not far away, concentrated in small stretches of rice plantation agro-systems in the region.  This behavioral seasonal concentration makes the species susceptible to poisoning and epizootic diseases. The findings suggest the need to re-categorize the Orinoco Goose population of the Middle Araguaia River as “Threatened” for the State of Tocantins due to the decline observed in the last 10 years, the maximum estimated population size, and the significant seasonal concentrations in a restricted area. At the same time, it is necessary to develop an action plan for its conservation in the surroundings of Ilha do Bananal, and throughout Brazil, where its threat status must be reviewed.