Abundância e tendência populacional do boto-da-amazônia-boliviana (Inia g. boliviensis) em sua principal área de distribuição na Bolivia, em uma série histórica de 20 anos

Abstract

The Bolivian River Dolphin (BRD, Inia boliviensis), a riverine cetacean endemic to one of the most threatened regions of South America, currently faces increasing anthropogenic and environmental pressures. This thesis represents the most comprehensive effort to assess the conservation status of this isolated subspecies, combining traditional field methods, emerging technologies, and a critical analysis aligned with IUCN international standards to support its future formal inclusion on the Red List. Over two decades of systematic monitoring have yielded data that, although preliminary, allow for an assessment of population trends. While statistical models do not confirm a definitive decline, field observations and accumulated expertise suggest legitimate concern regarding the species’ stability. To address the limitations of conventional methods, this thesis explores promising technological advances. The use of drones proved effective for counting individuals, offering more accurate and less intrusive aerial observations. Similarly, passive acoustic monitoring (PAM) with F-POD devices established a foundational understanding of the species’ temporal activity patterns, highlighting seasonal and diel variations. These tools enhance detection sensitivity and enable simultaneous monitoring across multiple habitats, optimizing data collection and resource use. All findings converge on a central objective: a preliminary evaluation of the conservation status of Inia boliviensis based on IUCN criteria. Among these, only Criterion A could be fully applied with currently available national data, supporting a reasoned proposal to recognize the subspecies as a distinct and threatened conservation unit. This effort addresses a key technical and scientific gap while raising the species’ profile in regional biodiversity conservation agendas. The thesis also underscores the cumulative and accelerating nature of threats facing the species, including bycatch, habitat degradation, pollution, increased river traffic, use as bait, and habitat fragmentation from hydroelectric development. Beyond academic contribution, this work serves as a call to action. By integrating robust data, innovative methodologies, and international alignment, it provides a sound basis for more effective public policy and conservation planning.