ABSTRACT
The rare Amazonian snake Eutrachelophis papilio is known from only five individuals, from four localities, belonging to its type-series, the more recent collected over 10 years ago. Here, we expand its distribution and describe its color in life for the first time. We also provide an estimate of its distribution area using the minimum convex polygon method and identify the values of anthropic pressure within its known distribution range with the Human Footprint Index. The new occurrence is located 291 km from the nearest known locality and its distribution is associated with pristine forests. Considering its rarity, and the absence of demographic and biological data, we suggest that the species should be classified as Data Deficient by IUCN criteria. (AU)
Subject(s)
Snakes , Forests , Animal DistributionABSTRACT
Abstract:Telemetry based on Global Positioning Systems (GPS) makes possible to gather large quantities of information in a very fine scale and work with species that were impossible to study in the past. When working with GPS telemetry, the option of storing data on board could be more desirable than the sole satellite transmitted data, due to the increase in the amount of locations available for analysis. Nonetheless, the uncertainty in the retrieving of the collar unit makes satellite-transmitted technologies something to take into account. Therefore, differences between store-on-board (SoB) and satellite-transmitted (IT) data sets need to be considered. Differences between SoB and IT data collected from two lowland tapirs (Tapirus terrestris), were explored by means of the calculation of home range areas by three different methods: the Minimum Convex Polygon (MCP), the Fixed Kernel Density Estimator (KDE) and the Brownian Bridges (BB). Results showed that SoB and IT data sets for the same individual were similar, with fix ranging from 63 % to 85 % respectively, and 16 m to 17 m horizontal errors. Depending on the total number of locations available for each individual, the home ranges estimated showed differences between 2.7 % and 79.3 %, for the 50 % probability contour and between 9.9 % and 61.8 % for the 95 % probability contour. These differences imply variations in the spatial coincidence of the estimated home ranges. We concluded that the use of IT data is not a good option for the estimation of home range areas if the collar settings have not been designed specifically for this use. Nonetheless, geographical representations of the IT based estimators could be of great help to identify areas of use, besides its assistance to locate the collar for its retrieval at the end of the field season and as a proximate backup when collars disappear. Rev. Biol. Trop. 64 (4): 1441-1450. Epub 2016 December 01.
Resumen:La telemetría basada en los sistemas de geopocisionamiento global (GPS) hace posible recopilar gran cantidad de información a escalas muy finas, y trabajar con especies imposibles de estudiar en el pasado. Al trabajar con telemetría de GPS, la opción de guardar información en la memoria interna del instrumento puede ser más deseable que sólo tener acceso a la información enviada vía satélite, debido a la mayor cantidad de localizaciones disponibles para analizar. No obstante, la incertidumbre de recuperar el collar hace que las tecnología de trasmisión vía satélite deba ser tenida en cuenta. Diferencias entre las bases de datos almacenadas en el collar (SoB) y las trasmitidas vía satélite (IT), recolectadas de dos individuos de Tapir de tierras bajas (Tapirus terrestris), son consideradas, en términos de las áreas de los rangos de hogar calculados con cada uno y mediante el uso de tres metodologías diferentes: Mínimo Polígono Convexo (MCP), Estimador de Densidad de Kernel Fijo (KDE) y los Puentes Brownianos (BB). Las bases de datos SoB e IT son similares, con tasas de acierto de localizaciones que oscilan entre 63 % to 85 % y errores horizontales de 16 m y 17 m respectivamente. Dependiendo del número total de localizaciones disponibles para cada individuo, los rangos de hogar estimados muestran diferencias entre 2.7 % y 79.3 %, para el contorno del 50 % de probabilidades, y entre 9.9 % y 61.8 % para el contorno del 95 % de probabilidades. Estas diferencias implican variaciones en la coincidencia espacial de los rangos de hogar estimados. Concluimos que el uso de la información trasmitida vía satélite no es una buena opción para la estimación de rangos de hogar, si la programción de los collares no ha sido diseñada específicamente para tal fin. Sin embargo, las representaciones geográficas de los estimados a partir de las bases de datos IT pueden ser de gran ayuda para la identificación de áreas de uso, además de su utilidad para la localización y recuperación de collares tras su liberación de los individuos monitoreados y como una base de datos de soporte en caso de pérdida del collar.
Subject(s)
Animals , Male , Female , Perissodactyla , Telemetry/instrumentation , Telemetry/methods , Satellite Communications/instrumentation , Geographic Information Systems/instrumentation , Homing Behavior , Time Factors , Sex Factors , Reproducibility of Results , Colombia , Animal Distribution , Datasets as Topic , IridiumABSTRACT
Home-range is the area used by an animal in its daily activities. Home-range studies provide data on species mating systems and territorial behavior. Our main goal was to estimate the Didelphis albiventris (Lund 1840) home-range in Mutum Island, Paraná River, Brazil. The study was carried out in 2008 from March to October on a 19.20 ha grid. The island is part of the Parana River Islands and Floodlands Federal Environmental Protection Area, with vegetation composed by Alluvial Semideciduous Seasonal Forest in a region of Subtropical Wet climate. The sampling effort was 3,360 traps-night resulting in 152 Didelphis albiventris (Lund 1840) captures. Forty-one Didelphis albiventris (Lund 1840) individuals were captured in 42 capture stations, composed by a trap placed on the floor and another in understory (2 m high). The animals were mostly terrestrial, independently of age or sex. Four females and five males, which were recaptured at least five times, were used to calculate home-range using the minimum convex polygon method. The mean home-range estimate was 2.33 ± 2.32 ha, similar to previous estimates provided by other methods, suggesting that our capture grid area, that was larger than usually applied for mark-capture studies for this species, have not underestimated the home-ranges. Evidences of the relation between individual home-range area and body mass were observed. Home-range overlaps occurred between males, females and males with females; the average overlap was 33.74%, which may be related to a promiscuous mating system, and suggests female territoriality.
Área de vida é a área usada por um animal em suas atividades diárias. Estudos de área de vida oferecem dados sobre os sistemas reprodutivos e comportamento territorial das espécies. Nosso objetivo foi estimar a área de vida de Didelphis albiventris (Lund 1840) na ilha Mutum, no rio Paraná, Brasil. O estudo foi realizado em 2008 de março a outubro em uma grade de 19,20 ha. Esta ilha é parte da área de proteção de ilhas e várzeas do rio Paraná e sua vegetação é composta por floresta estacional semidecidual aluvial sazonal com clima subtropical úmido. O esforço amostral foi de 3.360 armadilhas-noite resultando em 152 capturas de Didelphis albiventris (Lund 1840). Foram capturados 41 indivíduos nas 42 estações compostas por uma armadilha no solo e a dois metros de altura. A maioria dos animais foi capturada no solo, independente de idade ou sexo. Quatro fêmeas e cinco machos foram recapturados pelo menos cinco vezes e foram usados para calcular a área de vida mediante método de polígono mínimo convexo. A área de vida média estimada foi de 2,33 ha ± 2,32, similar às estimativas previamente descritas por outros métodos, sugerindo que o tamanho da grade de captura, maior que a usualmente empregada em estudos de marcação-recaptura com esta espécie, não subestimou as áreas de vida. Evidências da relação entre a área de vida e massa corporal dos indivíduos foram observadas. Sobreposição das áreas de vida (média = 33,74%) ocorreu entre machos, entre fêmeas e de machos com fêmeas, o que pode ser relacionado a um sistema de acasalamento promíscuo e territorialidade de fêmeas.