Carlos De Angelo

Comparing capture-recapture, mark-resight, and spatial mark-resight models for estimating puma densities via camera traps

Abstract Camera-trapping surveys, in combination with traditional capture–recapture or spatially explicit capture–recapture techniques, have become popular for estimating the density of individually identifiable carnivores. When only a portion of the population is uniquely identifiable, traditional and spatial mark–resight models provide a viable alternative. We reanalyzed a data set that used photographic capture–recapture methods to estimate the densities of pumas (Puma concolor) across 3 study sites in Belize, Argentina, and Bolivia using newer, more-advanced modeling including spatial and nonspatial mark–resight techniques. Additionally, we assessed how photo identification influenced density estimates by comparing estimates based on capture histories constructed by 3 independent investigators. We estimated the abundances of pumas using mark–resight models in program MARK and then estimated densities ad hoc. We also estimated densities directly using spatial mark–resight models implemented in a Bayesian framework. Puma densities did not vary substantially among observers but estimates generated from the 3 statistical techniques did differ. Density estimates (pumas/100 km2) from spatial mark–resight models were lower (0.22–7.92) and had increased precision compared to those from nonspatial capture–recapture (0.50–19.35) and mark–resight techniques (0.54–14.70). Our study is the 1st to estimate the density of a population of carnivores, where only a subset of the individuals are naturally marked, using camera-trapping surveys in combination with spatial mark–resight models. The development of spatial mark–resight and spatially explicit capture–recapture techniques creates the potential for using a single camera-trapping array to estimate the density of multiple, sympatric carnivores, including both partially marked and uniquely marked species. Resumen Los relevamientos con trampas-cámara en combinación con modelos tradicionales o espacialmente explícitos de captura–recaptura, se han convertido en metodologías muy utilizadas para estimar la densidad de carnívoros que pueden ser identificados individualmente. Cuando sólo una porción de la población puede ser identificada inequívocamente, los modelos de marcado–revisualización tradicionales y espacialmente explícitos proveen una alternativa viable. Reanalizamos un conjunto de datos, que se utilizó para estimar la densidad de pumas (Puma concolor) mediante el método fotográfico de captura–recaptura en 3 sitios de estudio en Belice, Argentina y Bolivia, utilizando modelos más novedosos y avanzados incluyendo técnicas de marcado–revisualización tradicionales y espacialmente explicitas. Adicionalmente, evaluamos cómo la identificación de fotografías influyó en las estimaciones de densidad, comparando estimaciones basadas en las historias de captura construidas por 3 investigadores independientes. Estimamos la abundancia de pumas usando modelos de marcado–revisualización en el programa MARK y luego estimamos las densidades ad hoc. También estimamos densidades usando modelos espaciales de marcado–revisualización espacialmente explícitos implementados en un marco Bayesiano. La densidad de pumas no varió sustancialmente entre observadores, pero las estimaciones generadas mediante los 3 modelos estadísticos fueron diferentes. Las densidades de pumas (pumas/100 km2) de modelos de marcado–revisualización espacialmente explícitos fueron más bajas (0.22–7.92) y aumentaron en precisión comparadas con aquellas de captura–recaptura (0.50–19.35) y técnicas de marcado–revisualización no espacialmente explícitos (0.54–14.70). Nuestro estudio es el primero en estimar la densidad mediante la utilización de datos de trampas-cámara en combinación con modelos marcado–revisualización espacialmente explícitos de una población de carnívoros donde sólo un subconjunto de individuos está marcado naturalmente. El desarrollo de técnicas de marcado–revisualización y captura–recaptura espacialmente explícitos ofrece la oportunidad de utilizar un mismo diseño de trampas-cámara para estimar la densidad de múltiples carnívoros simpátricos, incluyendo especies parcial o totalmente identificables individualmente.

Participatory networks for large-scale monitoring of large carnivores: pumas and jaguars of the Upper Paraná Atlantic Forest

Most large carnivores are secretive and threatened, and these characteristics pose problems for research on, and monitoring of, these species across extensive areas. Participatory monitoring, however, can be a useful tool for obtaining long-term data across large areas. Pumas Puma concolor and jaguars Panthera onca are the largest predators in the threatened Upper Parana Atlantic Forest. To survey the presence of these two species we established a participatory network of volunteers and a partnership with researchers in the three countries that share the Upper Parana Atlantic Forest (Argentina, Brazil and Paraguay). We trained participants in simple methods of collecting faeces and track imprints of large felids. Between 2002 and 2008 > 100 volunteers helped with monitoring, obtaining 1,633 records identified as pumas or jaguars across c. 92,890 km 2 . We confirmed jaguar presence in a large section of the Misiones Green Corridor in Argentina and in the largest protected areas of Brazil and Paraguay. Pumas exhibited a wider distribution, being recorded throughout Misiones province in Argentina and in some areas of Brazil and Paraguay where jaguars were not detected. Both species, and especially jaguars, were detected mainly in the few remaining medium and large forest fragments in this Forest. Although these carnivores are often in conflict with local people, their charisma and cultural significance makes them flagship species that motivated the participation of volunteers and institutions. Participatory monitoring allowed coverage of a vast area at relatively low cost whilst enhancing collaborative management policies among people and institutions from three countries.

ATLANTIC‐CAMTRAPS: a dataset of medium and large terrestrial mammal communities in the Atlantic Forest of South America

Our understanding of mammal ecology has always been hindered by the difficulties of observing species in closed tropical forests. Camera trapping has become a major advance for monitoring terrestrial mammals in biodiversity rich ecosystems. Here we compiled one of the largest datasets of inventories of terrestrial mammal communities for the Neotropical region based on camera trapping studies. The dataset comprises 170 surveys of medium to large terrestrial mammals using camera traps conducted in 144 areas by 74 studies, covering six vegetation types of tropical and subtropical Atlantic Forest of South America (Brazil and Argentina), and present data on species composition and richness. The complete dataset comprises 53,438 independent records of 83 species of mammals, includes 10 species of marsupials, 15 rodents, 20 carnivores, eight ungulates and six armadillos. Species richness averaged 13 species (±6.07 SD) per site. Only six species occurred in more than 50% of the sites: the domestic dog Canis familiaris, crab-eating fox Cerdocyon thous, tayra Eira barbara, south American coati Nasua nasua, crab-eating raccoon Procyon cancrivorus and the nine-banded armadillo Dasypus novemcinctus. The information contained in this dataset can be used to understand macroecological patterns of biodiversity, community, and population structure, but also to evaluate the ecological consequences of fragmentation, defaunation, and trophic interactions.