Regional conservation priorities for crocodylians in Bolivia

Abstract

Crocodylians are large predators and ecological keystone species in wetland ecosystems. In Bolivia a total of five species occur, all of which are members of the family Alligatoridae: Caiman yacare, C. latirostris, Melanosuchus niger, Paleosuchus palpebrosus, and P. trigonatus. Beginning in the mid-1800s, wild populations were reduced and threatened by unsustainable exploitation, commercial hunting, lack of wildlife law enforcement, and poor management strategies. Economic incentives that can be generated through the management of crocodylians and sustainable use of wildlife (SUW) programs have become key elements for conservation of the species and their habitats. Nevertheless, these programs must be designed based on solid scientific strategies to guarantee efficiency and sustainability. Adapted from successful conservation strategies for other species, we present the first country-wide range assessment of crocodylians in Bolivia. We evaluated the current state of knowledge and propose regional conservation priorities, integrating distribution and biological information available for Bolivian crocodylians. We carried out a literature search and review, and spatial data compilation to estimate the distribution range (Extent of Occurrence - EOO), characterize ecoregions (Crocodylian Geographic Regions - CGRs), and delineate areas with species occurrence and population surveys (Crocodylian Study Units – CSUs). Finally, ecoregions inside CSUs were defined as Crocodylian Conservation Units (CCUs), for which we developed a geographic priority setting. We categorized them as Regional Habitat Priority (RHP) areas with sufficient biological information to implement management and sustainable use programs aimed at species and habitat conservation, or as Regional Research Priority (RRP) areas with the absence or insufficience of biological information to prioritize research and monitoring programs. We reviewed 105 documents written from 1977 to 2017 and used spatial data from 44 documents. We estimated an EOO of 654,930 km2, defined 17 CGRs, 98 CSUs, and 167 CCUs, out of which 29 were categorized as RHP and 138 as RRP. This study is the first effort to develop a regional conservation plan as a scientific baseline that can facilitate decision-makers to prioritize future research, encourage habitat protection, and promote management and sustainable use programs to achieve effective long-term survival of crocodylians in Bolivia.