BackgroundThe threats facing Ecuador's Yasuní National Park are emblematic of those confronting the greater western Amazon, one of the world's last high-biodiversity wilderness areas. Notably, the country's second largest untapped oil reserves—called “ITT”—lie beneath an intact, remote section of the park. The conservation significance of Yasuní may weigh heavily in upcoming state-level and international decisions, including whether to develop the oil or invest in alternatives.Methodology/Principal FindingsWe conducted the first comprehensive synthesis of biodiversity data for Yasuní. Mapping amphibian, bird, mammal, and plant distributions, we found eastern Ecuador and northern Peru to be the only regions in South America where species richness centers for all four taxonomic groups overlap. This quadruple richness center has only one viable strict protected area (IUCN levels I–IV): Yasuní. The park covers just 14% of the quadruple richness center's area, whereas active or proposed oil concessions cover 79%. Using field inventory data, we compared Yasuní's local (alpha) and landscape (gamma) diversity to other sites, in the western Amazon and globally. These analyses further suggest that Yasuní is among the most biodiverse places on Earth, with apparent world richness records for amphibians, reptiles, bats, and trees. Yasuní also protects a considerable number of threatened species and regional endemics.Conclusions/SignificanceYasuní has outstanding global conservation significance due to its extraordinary biodiversity and potential to sustain this biodiversity in the long term because of its 1) large size and wilderness character, 2) intact large-vertebrate assemblage, 3) IUCN level-II protection status in a region lacking other strict protected areas, and 4) likelihood of maintaining wet, rainforest conditions while anticipated climate change-induced drought intensifies in the eastern Amazon. However, further oil development in Yasuní jeopardizes its conservation values. These findings form the scientific basis for policy recommendations, including stopping any new oil activities and road construction in Yasuní and creating areas off-limits to large-scale development in adjacent northern Peru.

Mineral licks are sites where a diverse array of mammals and birds consume soil (geophagy) or drink water, likely for mineral supplementation. The diversity of species that visit such sites makes them important for conservation, particularly given that hunters often target animals at licks. Use of mineral licks varies among species, with frugivores among the most common visitors but there is considerable temporal and spatial variation in lick use both within and among species. Camera traps triggered by heat and motion were used to document use of mineral licks by birds and non-volant mammals over a four-year period at a lowland forest site in eastern Ecuador. We obtained 7,889 photographs representing 23 mammal species and 888 photographs representing 15 bird species. Activity (photographs/100 trap-days) at the four licks varied from 89 to 292 for mammals and from six to 43 for birds. Tapirs (Tapirus terrestris), peccaries (Pecari tajacu, Tayassu pecari), deer (Mazama americana), and pacas (Cuniculus paca) were the most frequent mammal visitors; guans (Pipile pipile) and pigeons (Columba plumbea) were the most common birds. Use of licks varied diurnally and seasonally but patterns of use varied among species and sites. Mineral licks provide an important resource for many species but further studies are needed to determine the precise benefit(s) obtained and how benefits may vary with diet and other factors, such as rainfall

Ocelots ( Leopardus pardalis ) are common in lowland forests of Amazonia. We used camera traps to document the occurrence and activity of ocelots at a site in eastern Ecuador during 2005–2012 (15,058 trap-days). We accumulated 384 independent images of 16 males (147 images), 19 females (234 images), and 3 not assigned to individual or sex. Individuals varied in number of images (1 to > 50), number of camera locations (1–8), and number of months from first to last image (1–85). Photographic rate varied across years, from 15.3 to 29.9/1,000 trap-days in 2006 and 2010, respectively. Males and females were primarily active at night and showed similar hourly patterns of activity. Up to 3 individual males and 4 individual females were recorded at different camera locations each year. Resident males typically were photographed at more locations (mean of 4.1) than females (mean of 3.2). Results indicate that multiple ocelots, of both sexes, may be found within a relatively small (~650 ha) area of lowland forest in eastern Ecuador and emphasize the importance of the region for conservation of ocelots and other species. Los ocelotes ( Leopardus pardalis ) son felinos comunes en los bosques de tierras bajas de la Amazonía. Utilizamos cámaras trampa para documentar la ocurrencia y actividad de ocelotes en un sitio en el Este de Ecuador durante 2005–2012 (15.058 días-trampa). Acumulamos 384 imágenes independientes de 16 machos (147 fotografías), 19 hembras (234 fotografías), y tres a los que no se les asignó individuo o sexo. Los individuos variaron en número de imágenes (1 a > 50), número de locaciones de las cámaras (1 a 8) y en el número de meses desde la primera hasta la última imagen (1 a 85). La tasa de captura fotográfica varió a través de los años, de 15,3 a 29,9 / 1.000 días-trampa en 2006 y 2010, respectivamente. Machos y hembras fueron activos principalmente durante la noche y mostraron patrones similares de actividad por hora. Hasta tres individuos machos y cuatro individuos hembras fueron registrados en diferentes locaciones cada año. Machos residentes fueron fotografiados en más lugares (media de 4,1) que hembras (media de 3,2). Los resultados indican que varios ocelotes, de ambos sexos, pueden encontrarse dentro de un área relativamente pequeña (~ 650 ha) de bosques de tierras bajas en el Este de Ecuador y enfatizan en la importancia de la región para la conservación de ocelotes y otras especies.

Human activity can lead to changes in animal behavior and distribution patterns if the level of activity is high enough to cause disturbance. Both humans and other animals commonly use human-made trails in lowland tropical forest and, therefore, it is possible that use of trails by humans might affect the likelihood that animals would use those same trails. We investigated this possibility at a site in lowland forest of eastern Ecuador using camera traps to document numbers of people and numbers of other animals at a series of camera locations during January-March, 2014-2016. Human activity was higher on trails used by all visitors to the research station than on two research plots where human activity is restricted. Ungulates were the only group to show a strong negative relationship with human activity but only on trails open to all visitors; there was no apparent negative impact of human activity on research plots. Results suggest that the level of human activity along trails is not now causing negative impacts to most mammals but also that levels of activity should be monitored to ensure that any increase in human presence does not lead to negative responses by mammals.

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