2016-12-23T18:52:10

Assessing the status of tropical dry forest habitats using remote sensing technologies is one of the research priorities for Neotropical forests. We developed a simple method for mapping vegetation and habitats in a tropical dry forest reserve, Mona Island, Puerto Rico, by integrating the Normalized Difference vegetation Index (NDvI) from Landsat, topographic information, and high-resolution Ikonos imagery. The method was practical for identifying vegetation types in areas with a great variety of plant communities and complex relief, and can be adapted to other dry forest habitats of the Caribbean Islands. NDvI was useful for identifying the distribution of forests, woodlands, and shrubland, providing a natural representation of the vegetation patterns on the island. The use of Ikonos imagery allowed increasing the number of land cover classes. As a result, sixteen land-cover types were mapped over the 5 500 ha area, with a kappa coefficient of accuracy equal to 79 %. This map is a central piece for modeling vertebrate species distribution and biodiversity patterns by the Puerto Rico Gap Analysis Project, and it is of great value for assisting research and management actions in the island. Rev. Biol. Trop. 56 (2): 625-639. Epub 2008 June 30.

Headstarting refers to the raising of hatchlings in captivity and subsequently releasing them into the wild and it is a widely used tool to protect endangered species by increasing survivorship. Evaluating the success of headstart programs is necessary but challenging. We evaluated a headstart program for the endangered Mona Island iguana Cyclura cornuta stejnegeri by analyzing demographic and spatial data and by comparing growth rate, body condition, and external parasitic load of headstarted and wild iguanas. Hatchlings were released at about 3 yr age. Minimum survival rate was 40.3 %, at 7.6 to 48.3 mo after release. Most migrated from the release site back to the rearing facilities about 633 m away. Density around the rearing facility increased from 7.5 to 11.5 iguanas ha -1 (25 of 75 captures were headstarted iguanas). Released headstarted iguanas exhibited growth rates similar to the maxima observed in captive and wild mid-sized iguanas. Growth rates decreased immediately prior to release, indicating that husbandry practices ought to be reviewed. There was no evidence for an effect of captivity on susceptibility to external parasites. Increased local density indicates that the program was successful. However, the longer-term success remains unknown, as most headstarted iguanas returned to the headstart facility without establishing territories typical for adult wild Mona iguanas.

rango altitudinal entre los 120 y 494 msnm. Los especímenes corresponden a tres géneros, siete especies y siete subespecies siendo las más abundantes Battus polydamas polydamas y Parides eurimedes arriphus con 15 y 12 individuos, respectivamente. Las siete especies identificadas corresponden al 11,5% de las 61 reportadas para Colombia y al 29,2% de las 24 especies de Papilionidae registradas para toda la región Orinoquia. A nivel regional la riqueza de Papilioniade en Arauca es igual a la reportada en una localidad en el Meta (siete sp.) y menor que la del departamento de Casanare (nueve sp.). Reportamos la ampliación de la distribución geográfica de cuatro subespecies a nivel regional.

El orden Lepidoptera es uno de los taxones más diversos y conocidos de insectos. Sin embargo, hay aspectos ecológicos de este grupo que se han investigado poco en la Orinoquia colombiana. En el estudio se documenta la dinámica temporal de la riqueza y la abundancia de mariposas frugívoras en la sabana inundable del municipio de Arauca y su relación con las variables climáticas de temperatura y precipitación. El muestreo se realizó a 9 km de la cabecera municipal de Arauca, usando seis trampas Van Someren Rydon durante cinco días al mes a lo largo de 24 meses. Se registraron 227 individuos de 21 especies. Los estimadores no paramétricos de diversidad indicaron que el muestreo tuvo una representatividad de 87,9 a 91,2 % de las mariposas frugívoras del área. Los análisis de agrupamiento y de similitudes (ANOSIM) indicaron que la respuesta de la comunidad de mariposas corresponde al régimen unimodal de precipitación de la Orinoquia, con mayor riqueza de especies y abundancia durante los meses de lluvia. Se estableció que las temperaturas en los días de muestreo tuvieron un efecto negativo en las tasas de captura. Este trabajo representa la primera aproximación a la dinámica temporal de la riqueza y la abundancia de lepidópteros y su relación con las variables climáticas en el norte de la Orinoquia colombiana. © 2018. Acad. Colomb. Cienc. Ex. Fis. Nat.