Browsing by Autor "Leonardo Maffei"

Now showing 1 - 14 of 14

Área de acción, actividad y uso de hábitat del zorro patas negras, Cerdocyon thous, en un bosque seco
(Universidad Autónoma del Estado de México, 2003) Leonardo Maffei; Andrew Taber
"Se estudió el área de acción de tres zorros patas negras ( Cerdocyon thous) enun bosque seco de Santa Cruz, Bolivia a través de radiotelemetría durante un período de15 meses. Utilizando el Polígono Mínimo Convexo como estimador se encontró que losanimales ocuparon áreas entre 280 y 110 ha con un solapamiento mínimo (27 ha) entrevecinos. Los hábitos de los zorros son principalmente nocturnos, con la mayor actividadregistrada entre las 17:00 y las 8:00 horas. Prefirieron el bosque ribereño a los bosqueschaqueños o de serranía, aunque el primero estaba disponible en un área mucho menor."
Comparing capture-recapture, mark-resight, and spatial mark-resight models for estimating puma densities via camera traps
(Oxford University Press, 2014) Lindsey N. Rich; Marcella J. Kelly; Rahel Sollmann; Andrew J. Noss; Leonardo Maffei; Rosario Arispe; Agustín Paviolo; Carlos De Angelo; Yamil E. Di Blanco; Mario S. Di Bitetti
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.
Comparison of density estimation methods for mammal populations with camera traps in the <scp>K</scp>aa‐<scp>I</scp>ya del <scp>G</scp>ran <scp>C</scp>haco landscape
(Wiley, 2012) A. J. Noss; B. Gardner; Leonardo Maffei; Erika Cuéllar; R. Montaño; Alfredo Romero‐Muñoz; R. Sollman; Allan F. O’Connell
Abstract Sampling animal populations with camera traps has become increasingly popular over the past two decades, particularly for species that are cryptic, elusive, exist at low densities or range over large areas. The results have been widely used to estimate population size and density. We analyzed data from 13 camera trap surveys conducted at five sites across the K aa‐ I ya landscape, B olivian C haco, for jaguar, puma, ocelot and lowland tapir. We compared two spatially explicit capture–recapture ( SCR ) software packages: secr , a likelihood‐based approach, and SPACECAP , a B ayesian approach, both of which are implemented within the R environment and can be used to estimate animal density from photographic records of individual animals that simultaneously employ spatial information about the capture location relative to the sample location. As a non‐spatial analysis, we used the program CAPTURE 2 to estimate abundance from the capture–recapture records of individuals identified through camera trap photos combined with an ad hoc estimation of the effective survey area to estimate density. SCR methods estimated jaguar population densities from 0.31 to 1.82 individuals per 100 km 2 across the K aa‐ I ya sites; puma from 0.36 to 7.99; ocelot from 1.67 to 51.7; and tapir from 7.38 to 42.9. Density estimates using either secr or SPACECAP were generally lower than the estimates generated using the non‐spatial method for all surveys and species; and density estimates using SPACECAP were generally lower than that using secr . We recommend using either secr or SPACECAP because the spatially explicit methods are not biased by an informal estimation of an effective survey area. Although SPACECAP and secr are less sensitive than non‐spatial methods to the size of the grid used for sampling, we recommend grid sizes several times larger than the average home range (known or estimated) of the target species.
Efecto de las actividades humanas sobre la diversidad de mamíferos terrestres en un gradiente altitudinal
(2015) Lilliana Piedra; Leonardo Maffei
The effect ofhuman activity on terrestrial marnmals was studied with footprint counts in Guanacaste, Costa Rica (loo30"N, 85°40'W) in February 1998 (in fifty 2 m2 quadrats). The most cornmon species were Canis latrans, Didelphis marsupialis. Odoicoleus virginianus. Dasyprocta punctata andTapirus bairdii. No stastically significant association was found between humna activity and marnmal frequency in the footprint counts.
Estimación de la edad de fetos y estacionalidad reproductiva de urina (Mazama gouazoubira) en el Chaco boliviano
(2012) Verónica Chávez; Leonardo Maffei
Estimating Puma Densities from Camera Trapping across Three Study Sites: Bolivia, Argentina, and Belize
(Oxford University Press, 2008) Marcella J. Kelly; Andrew J. Noss; Mario S. Di Bitetti; Leonardo Maffei; Rosario Arispe; Agustín Paviolo; Carlos De Angelo; Yamil E. Di Blanco
Estimates of abundance are extremely valuable for species conservation, yet determining abundance for elusive, wide-ranging, carnivores is difficult. We estimated density of pumas using remote cameras across study sites in Bolivia, Argentina, and Belize. We used obvious and subtle markings to identify individual pumas in photographs and conducted double-blind identifications to examine the degree of agreement among investigators. Average agreement on identification between pairs of investigators was nearly 80.0% and 3-way agreement was 72.9%. Identification of pumas as different individuals was uncommon (7.8% pairwise, 0.69% 3-way disagreement) with the remainder described as unidentifiable. Densities of pumas varied consistently from site to site regardless of investigator. Bolivian pumas moved the shortest distances between camera stations and Argentinean pumas the longest, but distances among cameras and area covered by surveys varied among sites. We applied a correction factor to the Bolivian data to account for the small area surveyed and found that, averaged across investigator, Bolivia had significantly more pumas per 100 km2 (mean ± SD; 6.80 ± 1.5) than Belize (3.42 ± 1.3) or Argentina (0.67 ± 0.2). Numbers of pumas in Argentina match those of low-density North American sites, and those for Belize are consistent with the Pantanal and high-density North American sites. Densities of pumas can be reliably estimated with remote cameras for these sites, and our work presents the 1st density estimates for Central America and for forested environments in South America.
Geoffroy's cats at the northern limit of their range: activity patterns and density estimates from camera trapping in Bolivian dry forests
(Taylor & Francis, 2006) Erika Cuéllar; Leonardo Maffei; Rosario Arispe; Andrew J. Noss
We used camera traps to survey Geoffroy's cats, Oncifelis geoffroyi, at six dry forest sites in Bolivia. Cumulative activity patterns across all sites are principally nocturnal though the species is active by day in both summer and winter. At two sites the number of captures and recaptures was sufficient to estimate abundance using the software Capture, and in turn a population density of 9–40 per 100 km2 for the two sites. Geoffroy's cats are present in all dry forest types surveyed: Chaco savannas, Chaco dry forest, Chaco transitional forest, Chaco‐Chiquitano transitional forest, Chaco‐Cerrado transitional forest and Chiquitano dry forest. They are most abundant at the driest site, the only one with grassland formations and where ocelots are absent. Camera trapping records tend to be more numerous in the dry season, suggesting seasonal changes in behavior and habitat use. Resumen Empleamos trampas‐cámara para muestrear Oncifelis geoffroyi en seis sitios ubicados en bosques secos de Bolivia. El patrón de actividad en todos los sitios es principalmente nocturno, pero la especie puede estar activa de día en verano como en invierno. En dos sitios tuvimos suficiente capturas y recapturas para estimar abundancia usando el programa Capture, y luego una densidad poblacional de 9–40/100 km2 para los dos sitios. Oncifelis geoffroyi está presente en todas los tipos de bosques secos muestreados: sabanas chaqueñas, bosque seco chaqueño, bosque transicional chaqueño, bosque transicional Chaco‐Chiquitano, bosque transitional Chaco‐Cerrado, y bosque seco Chiquitano. Es más abundante en el sitio con menor precipitación, el único sitio con formaciones de pampas y donde es ausente Leopardus pardalis. Se tiene más registros con trampas‐cámara en la época seca, sugiriendo cambios estacionales en comportamiento y uso de hábitat.
How Small is too Small? Camera Trap Survey Areas and Density Estimates for Ocelots in the Bolivian Chaco
(Wiley, 2007) Leonardo Maffei; Andrew J. Noss
ABSTRACT Studies on carnivores, which are generally difficult to observe directly because they are elusive and nocturnal, are carried out through indirect methods, e.g. , camera trapping and radiotracking. The first method has been used to estimate population densities of species that can be differentiated as individuals using unique pelage patterns. However, the use of capture–recapture methodology has raised doubts regarding the estimation of the sampling area around the camera traps, which is obtained using maximum distances traveled by individuals photographed at two or more different locations. In this paper, the results from camera traps are compared with a radiotracking study carried out simultaneously with ocelots ( Leopardus pardalis ) to confirm whether maximum distances observed in camera traps coincide with ranging patterns determined from radio telemetry, and in turn whether the sampling areas estimated from camera traps are appropriate for estimating density. Mean maximum distance moved was 2880 m according to camera trap records during a 60‐d survey period while, with radiotracking, the maximum distance moved was 3176 m during the same period. The difference is not significant, and the sampling areas estimated with camera traps to assess ocelot density are reliable. However, if the area covered by cameras is reduced to less than three to four times average home range for the target species, then density estimates from camera trapping are exaggerated because of the reduced observed distances and the fact that multiple individuals can overlap in relatively small areas.
Ocelot (<i>Felis pardalis</i>) population densities, activity, and ranging behaviour in the dry forests of eastern Bolivia: data from camera trapping
(Cambridge University Press, 2005) Leonardo Maffei; Andrew J. Noss; Erika Cuéllar; Damián I. Rumiz
In comparison with the Neotropical big cats, jaguar ( Panthera onca L.) and puma ( Felis concolor L.), medium and small felids are poorly studied. Furthermore, studying wild felids in forest habitats is extremely difficult using direct methods given that most species are principally nocturnal and secretive (Gittleman 1996). Indirect methods are therefore particularly important, e.g. radio-telemetry (Emmons 1987, 1988; Konecny 1989, Ludlow & Sunquist 1987) or camera trapping (Maffei et al . 2002, Trolle & Kéry 2003). Using systematic camera trap surveys, we compare the population density of ocelots ( Felis pardalis L.) across five Bolivian dry-forest sites with different habitat types and/or annual rainfall regimes (Table 1). We hypothesize that ocelot densities will decline as rainfall declines. In addition, we estimate the population of ocelots in the 34 400-km 2 Kaa-Iya del Gran Chaco National Park. Finally, we describe and evaluate additional ecological information provided by camera trapping: activity patterns relative to seasonality and moon phase, sex ratios, ranging patterns and relative abundance compared with sympatric felids.
One thousand jaguars (<i>Panthera onca</i>) in Bolivia's Chaco? Camera trapping in the Kaa‐Iya National Park
(Wiley, 2004) Leonardo Maffei; Erika Cuéllar; Andrew J. Noss
Abstract This paper reports on efforts to trap jaguars Panthera onca on camera in the dry forests of the Kaa‐Iya del Gran Chaco National Park in Bolivia. Ad hoc camera trapping provided certain information on jaguar presence and habits, but was limited in application. Activity patterns showed that jaguars are active all day, particularly at one of three sites, with peaks in the morning and evening the more common pattern. Minimum observed home range was variable, with males (up to 65 km 2 ) occupying more area than females (up to 29 km 2 ). The authors adapted systematic methodologies first developed to survey tigers in India, based on individually distinctive pelage patterns in tigers and jaguars. Abundance is estimated using capture–recapture statistical analysis, and a sample area defined based on the maximum distance that individual jaguars move during the sample period. The methodology has proved successful for jaguars in dry Chaco forest, population densities of 1/30–45 km 2 and 1/20 km 2 are estimated in the two most extensive landscape systems of Kaa‐Iya. The entire 34 400 km 2 protected area is estimated to sustain a population of over 1000 adult and juvenile jaguars, the largest single population of jaguar reported anywhere, and a viable population for long‐term jaguar conservation.
Reproduccion de Dasypus novemcinctus en el Izozog, Santa Cruz, Bolivia
(2003) Clara R. Rojas-Suarez; Leonardo Maffei
Serosurvey of Small Carnivores in the Bolivian Chaco
(Wildlife Disease Association, 2007) Christine V. Fiorello; Andrew J. Noss; Sharon L. Deem; Leonardo Maffei; Edward J. Dubovi
Five species of Bolivian carnivores, including nine Geoffroy's cats (Oncifelis geoffroyi), ten ocelots (Leopardus pardalis), one jaguarundi (Herpailurus yaguarondi), nine pampas foxes (Pseudalopex gymnocercus), and five crab-eating foxes (Cerdocyon thous) were sampled between March 2001 and April 2005 and tested for antibodies to common pathogens of domestic carnivores. Carnivores were trapped in three areas: a village, the region between human settlements and a protected area, and within Kaa-Iya National Park, Bolivia. Antibodies to canine distemper virus were detected in ocelots and pampas foxes. Antibodies to canine parvovirus were detected in pampas foxes and crab-eating foxes. Geoffroy's cats and all of the ocelots tested positive for antibodies to feline calicivirus (FCV), while fewer than half of Geoffroy's cats and no ocelots had antibodies to feline panleukopenia (FPV). These results confirm that these species of Bolivian carnivores are not naïve to common pathogens of domestic carnivores, and seropositive animals were found in villages as well as in the national park.
Temporal separation between jaguar and puma in the dry forests of southern Bolivia
(Cambridge University Press, 2010) Alfredo Romero‐Muñoz; Leonardo Maffei; Erika Cuéllar; Andrew J. Noss
Abstract: Despite the potential importance of temporal separation for the coexistence of competing species, no study has found significant segregation at the circadian level between jaguar ( Panthera onca ) and puma ( Puma concolor ) in sympatry. Using data from camera trap surveys (wet and dry seasons), we have evaluated the activity patterns of both species and their potential prey at four areas in the dry forest of the Bolivian Chaco. We tested if temporal separation existed between these two species, and if their activity was related to that of a particular prey. At most sites, activity patterns of jaguar and puma did not vary significantly between seasons, except for puma at one site. There were no differences between sexes for any cat species at any site. At three sites we found statistically significant differences in the activity patterns of jaguar and puma, as they showed a clear temporal segregation. None of them followed the activity patterns of any particular prey species across sites. The latter suggests that segregation is influenced by avoidance behaviour between the two felid species. Therefore, temporal separation may be an important behavioural factor promoting the coexistence of jaguar and puma in some areas of this dry forest.
The jaguarundi (puma yagouaroundi)In the kaa iya del gran chaco national park,Santa Cruz, Bolivia
(Smithsonian Institution, 2007) Leonardo Maffei; Andrew J. Noss; Christine V. Fiorello
Jaguarundis are felids that inhabit almost all habitat types below 2200 m, but basic aspects of their biology and behaviour are still unknown. This study wa...