Ongoing declines for the world's amphibians in the face of emerging threats.

Systematic assessments of species extinction risk at regular intervals are necessary for informing conservation action1,2. Ongoing developments in taxonomy, threatening processes and research further underscore the need for reassessment3,4. Here we report the findings of the second Global Amphibian Assessment, evaluating 8,011 species for the International Union for Conservation of Nature Red List of Threatened Species. We find that amphibians are the most threatened vertebrate class (40.7% of species are globally threatened). The updated Red List Index shows that the status of amphibians is deteriorating globally, particularly for salamanders and in the Neotropics. Disease and habitat loss drove 91% of status deteriorations between 1980 and 2004. Ongoing and projected climate change effects are now of increasing concern, driving 39% of status deteriorations since 2004, followed by habitat loss (37%). Although signs of species recoveries incentivize immediate conservation action, scaled-up investment is urgently needed to reverse the current trends.

Threatened amphibians sheltered under the big cat's umbrella: conservation of jaguars Panthera onca (Carnivora: Felidae) and endemic herpetofauna in Central America / Anfibios amenazados se refugiaron bajo la sombrilla del gato grande: evaluación de la conservación del jaguar Panthera onca (Carnivora: Felidae) y la herpetofauna endémica en Centro América

Abstract The umbrella species concept posits that protection of a single, wide-ranging species may confer protection to a large number of sympatric species. Due to their large home ranges, widespread distribution in the Mesoamerican Biodiversity Hotspot (MBH), and status as the focal species of numerous conservation initiatives, the jaguar Panthera onca is an ideal species to evaluate the umbrella strategy. After ground-truthing jaguar corridors from 2009-2016, we tested the umbrella value of jaguars for endemic herpetofauna (Amphibia, Reptilia) in Nuclear Central America (NCA), a ~ 370 000 km² sub-region of the MBH. NCA contains the greatest density of threatened reptiles in the Western Hemisphere and harbors extraordinary high diversity of amphibians, the most threatened class of vertebrate worldwide. Of the 304 regional endemics in NCA, the distributions of 187 (61.5 %) species of amphibians and reptiles overlapped ground-truthed jaguar range. The distributions of 14 reptiles, including a critically endangered Bothriechis spp. and two endangered Norops spp., occur exclusively within jaguar distribution. Similarly, the distributions of 19 amphibians, including four critically endangered Craugastor spp. and two critically endangered Plectrohyla spp. occur entirely within jaguar distribution. Our results indicate greater effectiveness of ground-truthed jaguar distribution than modeled and randomly selected networks in overlapping the distributions of endemic herpetofauna, especially threatened amphibians, in NCA. Substantiation of multi-taxa dependence on habitat in jaguar distribution would strengthen justification for wider application of the umbrella strategy beyond NCA and aid conservation planning in the MBH.

Resumen Las especies sombrilla son aquellas cuya conservación confiere protección a un gran número de especies simpátricas. Debido a sus ámbitos hogareños extensos, a una distribución generalizada en el Hotspot de Biodiversidad de Mesoaméricana (MBH), y su estatus como especie focal de numerosas iniciativas de conservación, el jaguar Panthera onca es una especie ideal para evaluar la estrategia sombrilla. Evaluamos el valor de los jaguares como estrategia sombrilla para la herpetofauna endémica en Centro América Nuclear (NCA), una subregión de ~ 370 000 km² que se encuentra dentro del MBH. La NCA contiene la mayor densidad de reptiles amenazados en el hemisferio occidental y alberga una diversidad extraordinaria de anfibios, que es la clase de vertebrados más amenazada del mundo. De las 304 especies endémicas regionales presentes en el NCA, las distribuciones de 187 (61.5 %) se sobrepusieron al área de distribución del jaguar verificada. Las distribuciones de 14 reptiles, incluyendo una Bothriechis spp. (en Peligro Crítico) y dos Norops spp. (en Peligro de Extinción), se dan exclusivamente dentro del rango del jaguar. Similarmente, 19 especies de anfibios, incluidas cuatro Craugastor spp. (en Peligro Crítico) y dos Plectrohyla spp. (en Peligro Crítico) están presentes exclusivamente dentro del área de distribución del jaguar. Nuestros resultados indican que los corredores verificados para el jaguar coinciden mejor con las distribuciones de la herpetofauna endémica dentro del NCA, especialmente anfibios, en comparación con los corredores modelados y seleccionados al azar. La confirmación del traslape de la distribución del hábitat del jaguar con la de múltiples taxones fortalece la justificación de una aplicación más amplia de la estrategia sombrilla, aún más allá del NCA, contribuyendo también en la selección de áreas de conservación previamente subestimadas dentro del MBH.

Estimating large carnivore populations at global scale based on spatial predictions of density and distribution - Application to the jaguar (Panthera onca).

Broad scale population estimates of declining species are desired for conservation efforts. However, for many secretive species including large carnivores, such estimates are often difficult. Based on published density estimates obtained through camera trapping, presence/absence data, and globally available predictive variables derived from satellite imagery, we modelled density and occurrence of a large carnivore, the jaguar, across the species' entire range. We then combined these models in a hierarchical framework to estimate the total population. Our models indicate that potential jaguar density is best predicted by measures of primary productivity, with the highest densities in the most productive tropical habitats and a clear declining gradient with distance from the equator. Jaguar distribution, in contrast, is determined by the combined effects of human impacts and environmental factors: probability of jaguar occurrence increased with forest cover, mean temperature, and annual precipitation and declined with increases in human foot print index and human density. Probability of occurrence was also significantly higher for protected areas than outside of them. We estimated the world's jaguar population at 173,000 (95% CI: 138,000-208,000) individuals, mostly concentrated in the Amazon Basin; elsewhere, populations tend to be small and fragmented. The high number of jaguars results from the large total area still occupied (almost 9 million km2) and low human densities (< 1 person/km2) coinciding with high primary productivity in the core area of jaguar range. Our results show the importance of protected areas for jaguar persistence. We conclude that combining modelling of density and distribution can reveal ecological patterns and processes at global scales, can provide robust estimates for use in species assessments, and can guide broad-scale conservation actions.