Simple assessments of age and spatial population structure can aid conservation of poorly known species

Abstract

The IUCN Red List is challenged with assessing the conservation status of species on which reliable demographic and distribution parameters are lacking. The hotly debated SAFE index, however, measures the “species’ ability to forestall extinction” and only requires information on population size. Nonetheless, both conservation assessment systems neglect the role of non-breeding population fractions in conservation. We conducted simple surveys to ascertain the spatial and population structure and conservation threats of the Endangered red-fronted macaw Ara rubrogenys, endemic to the Bolivian Andes. The area of occupancy (ca. 2600Km2) encompassed eight breeding and six non-breeding areas, occupied by 807 individuals. By combining population-fraction censuses with the proportion of juveniles (8.6%), we inferred a breeding population of less than 100 pairs clumped in 38–40 nesting sites, with non-breeders representing ca. 80% of the population. While this increase in data quality raises questions as to whether the species should be upgraded to Critically Endangered, the SAFE index rendered questionable guidance for conservation triage. Conservation threats were spatially identified according to spatio-temporal and life-stage population structures and seasonal changes in habitat use. Several sources of habitat loss were widespread but, contrary to expectation, habitat-use models indicated that red-fronted macaws were not tied to forest remnants. Instead, they made use of agricultural lands resulting in conflicts with farmers. Awareness campaigns should focus on a few selected locations to resolve this conflict and reduce the uptake of individuals for use as pets, as the most effective way to increase population size in the medium-term.