scholarly journals Habitat use, fruit consumption, and population density of the black-headed night monkey, Aotus nigriceps, in Southeastern Peru

2019 ◽  
Author(s):  
William. D. Helenbrook ◽  
Madison L. Wilkinson ◽  
Jessica A. Suarez
Keyword(s):  
Population Density ◽  
Habitat Use ◽  
Secondary Forest ◽  
Density Estimates ◽  
Field Station ◽  
Tree Cavities ◽  
Size Population ◽  
Single Field ◽  
Los Grupos ◽  
Species Being

ABSTRACTThe study of wild black-headed night monkey (Aotus nigriceps) ecology is limited to a single field station, despite the species being found across a vast distributional range in the Amazon. We studied several aspects of their ecology, specifically habitat use, group size, population density, and diet. All sampled groups were found in secondary tropical rainforest, often dominated by either native bamboo or cane species. Sleeping sites were often in bamboo stands, though groups were also found in cane thickets and lianas. This is in contrast to other Aotus studies which have found groups living in tree cavities and lianas. Population density estimates varied between field sites (19 and 50 individuals per km2), but both were consistent with other Aotus studies (31-40 individuals per km2). And, twelve seed species were recovered from fecal samples over the course of two field seasons, dominated primarily by Cecropiaceae, Piperaceae and Moraceae. Our results suggest that the black-headed night monkey can survive and even thrive in secondary forest, feeding extensively on pioneer species, occupying a range of forest types, all while living in proximity to people (<1km).RESUMOEl estudio de la ecología del mono nocturno salvaje (Aotus nigriceps) se limita a una única estación de campo, a pesar de que la especie se encuentra en un vasto rango de distribución en el Amazonas. Estudiamos varios aspectos de su ecología, específicamente el uso del hábitat, el tamaño del grupo, la densidad de población y la dieta. Todos los grupos muestreados se encontraron en la selva tropical secundaria, a menudo dominada por bambú nativo o especies de caña. Los sitios donde dormían a menudo se encontraban en puestos de bambú, aunque también se encontraron grupos en matorrales de caña y lianas. Esto contrasta con otros estudios de Aotus que han encontrado grupos que viven en cavidades de árboles y lianas. Las estimaciones de densidad de población variaron entre los sitios de campo (19 y 50 individuos por km2), pero ambos fueron consistentes con otros estudios de Aotus (31-40 individuos por km2). Y, doce especies de semillas fueron recuperadas de muestras fecales, dominadas principalmente por Cecropiaceae, Piperaceae y Moraceae. Nuestros resultados sugieren que el mono nocturno de cabeza negra puede sobrevivir e incluso prosperar en bosques secundarios, alimentándose ampliamente de especies pioneras, ocupando una variedad de tipos de bosques, mientras viven cerca de personas (<1 km).

scholarly journals Habitat use, fruit consumption, and population density of the black-headed night monkey, Aotus nigriceps, in southeastern Peru

2020 ◽  
Vol 50 (1) ◽  
pp. 37-43 ◽  
Author(s):  
William. D. HELENBROOK ◽  
Madison L. WILKINSON ◽  
Jessica A. SUAREZ
Keyword(s):  
Population Density ◽  
Habitat Use ◽  
Tropical Rainforest ◽  
Group Composition ◽  
Secondary Forest ◽  
Forest Types ◽  
Density Estimates ◽  
Monkey Species ◽  
Tree Cavities ◽  
Distribution Ranges

ABSTRACT The black-headed night monkey, Aotus nigriceps, has one of the largest distribution ranges of the 11 night monkey species found across Central and South America. Yet, only three studies have focused on their ecology, describing considerable variation in habitat, group composition, and population density. Therefore, we analyzed habitat use, group composition, population density, and diet of 14 groups at two field sites in southeastern Peru. All sampled groups were found in secondary tropical rainforest, often dominated by native bamboo species. Half of the observed sleeping sites were in bamboo stands, though groups also emerged from cane thickets and lianas. This contrasts with other Aotus studies which have found groups living in tree cavities and lianas. Population density estimates for both sites were 19 and 50 individuals per km2, outside the range previously reported for A. nigriceps (31−34 individuals per km2). We recovered seeds of 12 species from fecal samples over the course of two field seasons, belonging mainly to Cecropiaceae, Piperaceae and Moraceae. Our results suggest that the black-headed night monkey in Peru can survive and even thrive in secondary forest, feeding extensively on pioneer species, occupying a range of forest types, all while living near human settlements.

scholarly journals Multinomial-Poisson mixture models reveal unexpected higher density estimates of an Andean threatened bird

2018 ◽  
Author(s):  
D. A. Gómez-Hoyos ◽  
O. H. Marín-Gómez ◽  
Y. L. Caicedo Ortiz
Keyword(s):  
Population Density ◽  
Mixture Models ◽  
Secondary Forest ◽  
Riparian Forest ◽  
Distance Sampling ◽  
Sampling Effort ◽  
Density Estimates ◽  
Poisson Mixture ◽  
Point Counts ◽  
Model Based

AbstractMultinomial-Poisson mixture models reveal unexpected higher density estimates of an Andean threatened bird.Distance sampling and repeated counts are important tools to estimate population density of birds with low detectability. Here we use model based approach to assess the population density of a threatened bird, the Multicolored Tanager (Chlorochrysa nitidissima). We conducted 144 fixed point counts samplings to record all the individuals of the Multicolored Tanager detected by visual and aural observations from different habitats (forest edge, mature, secondary, and riparian forest), during four months in an Important Bird Area of Central Andes of Colombia. We used spatially replicated counts, distance sampling, and multinomial- Poisson mixture models to estimate the population density of the Multicolored Tanager. Accumulated sampling effort was of 576 repetitions in 144 point counts with 96 h of observation. The Multinomial-Poisson mixture model showed the best fit due low variance of density estimations in comparison to the conventional distance sampling and the spatially replicated counts. Results of this model evidenced a remarkable higher density estimates (1.3 – 2.05 individuals/ha) of the Multicolored Tanager, particularly in mature and secondary forest, as a result of detection correction, instead of sampling effort, by our model based analysis in contrast to index density used in previous studies. We discuss the advantages of model based methods over density indexes in designs monitoring programs of endangered species as the Multicolored Tanager, in order to obtain better and comparable assessment of density estimations along multiple localities.ResumenLa combinación de modelos multi-nominales y Poisson revelan estimaciones de densidad altas inesperadas en un ave amenazada Andina. Los muestreos por distancias y los conteos repetidos son herramientas importantes para estimar la densidad de población de aves con baja detección. Aquí utilizamos un enfoque basado en modelos para evaluar la densidad de población de un ave amenazada, la tangara multicolor (Chlorochrysa nitidissima). Realizamos 144 muestreos de conteos de puntos fijos para registrar todos los individuos de la tangara multicolor detectados por observaciones visuales y auditivas en diferentes hábitats (borde del bosque, bosque maduro, bosque secundario y bosque ribereño), durante cuatro meses en un Área Importante para la Conservación de las Aves en los Andes centrales de Colombia. Utilizamos conteos replicados espacialmente, muestreos de distancia y la combinación de modelos multi-nominales y Poisson para estimar la densidad de población de la tangara multicolor. El esfuerzo de muestreo acumulado fue de 576 repeticiones en 144 puntos de conteo con 96 h de observación. La combinación de modelos multi-nominales y Poisson mostró el mejor ajuste debido a la baja varianza de las estimaciones de densidad en comparación con el muestreo de distancias y los conteos replicados espacialmente. Los resultados de este modelo evidenciaron una notable estimación de mayor densidad (1.3 – 2.05 individuos / ha) de la tangara multicolor, principalmente en bosques maduros y secundarios, como resultado de la corrección de la detección por nuestro análisis basado en modelos, en lugar del esfuerzo de muestreo, en contraste con los índices de densidad utilizados en estudios previos. Discutimos las ventajas de los métodos basados en modelos sobre los índices de densidad en los diseños de programas de monitoreo de especies en peligro como la tangara multicolor, con el fin de obtener una evaluación mejor y comparable de las estimaciones de densidad a lo largo de múltiples localidades.

Density and activity patterns of ocelot populations in Yasuní National Park, Ecuador

Mammalia ◽  
2016 ◽  
Vol 80 (4) ◽  
Author(s):  
Julia Salvador ◽  
Santiago Espinosa
Keyword(s):  
Population Density ◽  
Habitat Loss ◽  
National Park ◽  
Conservation Status ◽  
Activity Patterns ◽  
Camera Trap ◽  
Oil Extraction ◽  
Density Estimates ◽  
Yasuni National Park ◽  
Ecuadorian Amazon

AbstractOcelots were historically hunted for their skins but habitat loss is now their most serious threat, causing rapid declines in populations throughout their range. Ocelot abundance has been estimated for various locations across the Neotropics, but we still lack this information from some countries, including Ecuador. Knowing whether ocelot abundance is increasing or decreasing is important to assess the conservation status of this species and the conditions of its habitats in the Ecuadorian Amazon and in the region. To determine whether ocelot abundance and its behavior are affected by human-related activities, camera-trap surveys were carried out in two localities of Yasuní National Park (YNP), one that has experienced hunting, oil extraction, and roads (Maxus Road) and one that is largely unaffected by these activities (Lorocachi). During the survey, 35 and 36 individual ocelots were photographed in Maxus Road and Lorocachi, respectively. Population density estimates were similar for both localities, ranging from 0.31 (SE±6) to 0.85 (SE±17) ocelots/km

scholarly journals Anurans of a disturbed area in Jarú, Rondônia, Brazil

Check List ◽  
2012 ◽  
Vol 8 (1) ◽  
pp. 083 ◽  
Author(s):  
Liliana Piatti ◽  
Paulo Matthes Orlandi de Amaro ◽  
Jhonatas Fernando de Jesus Araújo ◽  
Vitor Quadros Altamore Sanches ◽  
Paulo Sérgio Bernarde
Keyword(s):  
Secondary Forest ◽  
Amazon Forest ◽  
Pitfall Traps ◽  
Disturbed Area ◽  
Disturbed Areas ◽  
Species Being

This paper presents a checklist of anurans species and their distribution in a disturbed area in the municipality of Jarú, Rondônia state, Brazil. Nineteen species belonging to eight families were sampled with pitfall traps and time constrained searches. About 70% of the species were found in a secondary forest and 40% were found only in this environment, while about 57% were found in pastures, with 26% of species being registered only in this habitat. Our results were similar to those of previous studies in other disturbed areas of Rondônia. Species that can be found in different habits were unevenly distributed, with forested environments harboring more species. Despite its nearness to Cerrado and the large number of open areas available, most species found are typical of the Amazon forest.

scholarly journals Geospatial characterizing of Under-Five Mortality in Alexandria, Egypt

2021 ◽  
Author(s):  
Mahmoud Adel Hassan ◽  
Ahmed Mohamed Ramadan ◽  
Mohamed Mostafa Tahoun ◽  
Abdelrahman Omran ◽  
Shimaa Gad El-karim Ali ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Spatial Distribution ◽  
Cardiovascular Diseases ◽  
Population Density ◽  
Spatial Pattern ◽  
Under Five ◽  
Size Population ◽  
Access To Water ◽  
Alexandria City ◽  
Low Incidence

This study aimed to identify geo-spatial pattern of under-five mortality (U5M) in Alexandria and its key determinants. We analyzed the geospatial distribution of 3064 deaths registered at 24 health offices reported from January 2018 to June 2019. The localities of Alexandria city were clustered into high and low incidence areas. Neonates represented 58.7% of U5M, while post-neonates and children were 31.1%, 10.2% respectively. Male deaths were significantly higher (P=0.036). The main leading causes of U5M were prematurity (28.32%), pneumonia (11.01%), cardiac arrest (10.57%), congenital malformation (9.95%), and childhood cardiovascular diseases (9.20%). Spatial distribution of U5M (including the most common three causes) tend to be clustered in western parts of Alexandria (El Hawaria, Bahig, Hamlis and Ketaa Maryiut). Another 9 clusters are at risk of being hotspots. Illiteracy, divorce, and poor locality characteristics (household size, population density, and access to water supply and sanitation), were statistically significant predictors of U5M.

Rapid collapse of a population of Dieffenbachia spp., plants used for tadpole-rearing by a poison-dart frog (Oophaga pumilio) in a Costa Rican rain forest

2014 ◽  
Vol 30 (6) ◽  
pp. 615-619 ◽  
Author(s):  
Mark J. McKone ◽  
Jonathan W. Moore ◽  
Christopher W. Harbison ◽  
Ian C. Holmen ◽  
Hillary C. Lyons ◽  
...  
Keyword(s):  
Secondary Forest ◽  
Costa Rican ◽  
Primary Forest ◽  
Rapid Decline ◽  
Field Station ◽  
La Selva ◽  
Oophaga Pumilio ◽  
North Eastern ◽  
Pecari Tajacu ◽  
Almost All

Abstract:Amphibian populations have been declining worldwide, with multiple potential causes. At La Selva field station in north-eastern Costa Rica, previous work has shown that populations of many amphibians have decreased significantly since the 1970s, especially in primary forest. Starting in 1998, we investigated one of the most common frog species at La Selva, the poison-dart frog Oophaga pumilio (= Dendrobates pumilio). In a survey of 50 plots of 100 m2 in 1998, adult frogs were 4.6 times more abundant in secondary forest than in primary forest. Tadpoles were found only in secondary-forest plots. Almost all (89%) of the tadpoles were found in leaf axils of Dieffenbachia spp., which were much more abundant in secondary-forest than in primary-forest plots. The greater abundance of Dieffenbachia spp. in secondary forest was confirmed in a broad survey of ~11 km of trails within La Selva in 2002. When the same trails were resampled in 2012, Dieffenbachia spp. had been extirpated from 72% of the 50-m segments where plants were present in 2002; abundance was greatly reduced in the few trail segments where any Dieffenbachia spp. remained in 2012. The loss of Dieffenbachia spp., especially in secondary forest, removed the species most often used by O. pumilio for tadpole rearing. Based on counts of calling frogs in 2010, there was no difference in O. pumilio abundance in primary versus secondary forest, in striking contrast to multiple earlier surveys that found much greater frog abundance in secondary forest. We propose that the reason for the rapid decline in Dieffenbachia spp. is herbivory by the collared peccary (Pecari tajacu), which has increased in abundance at La Selva in recent years. A likely consequence is continued reduction in O. pumilio populations.

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