Guido Fabián Medina-Rangel

Creation of forest edges has a global impact on forest vertebrates

Forest edges influence more than half of the world’s forests and contribute to worldwide declines in biodiversity and ecosystem functions. However, predicting these declines is challenging in heterogeneous fragmented landscapes. Here we assembled a global dataset on species responses to fragmentation and developed a statistical approach for quantifying edge impacts in heterogeneous landscapes to quantify edge-determined changes in abundance of 1,673 vertebrate species. We show that the abundances of 85% of species are affected, either positively or negatively, by forest edges. Species that live in the centre of the forest (forest core), that were more likely to be listed as threatened by the International Union for Conservation of Nature (IUCN), reached peak abundances only at sites farther than 200–400 m from sharp high-contrast forest edges. Smaller-bodied amphibians, larger reptiles and medium-sized non-volant mammals experienced a larger reduction in suitable habitat than other forest-core species. Our results highlight the pervasive ability of forest edges to restructure ecological communities on a global scale.

BIOFRAG - a new database for analyzing BIOdiversity responses to forest FRAGmentation

Habitat fragmentation studies have produced complex results that are challenging to synthesize. Inconsistencies among studies may result from variation in the choice of landscape metrics and response variables, which is often compounded by a lack of key statistical or methodological information. Collating primary datasets on biodiversity responses to fragmentation in a consistent and flexible database permits simple data retrieval for subsequent analyses. We present a relational database that links such field data to taxonomic nomenclature, spatial and temporal plot attributes, and environmental characteristics. Field assessments include measurements of the response(s) (e.g., presence, abundance, ground cover) of one or more species linked to plots in fragments within a partially forested landscape. The database currently holds 9830 unique species recorded in plots of 58 unique landscapes in six of eight realms: mammals 315, birds 1286, herptiles 460, insects 4521, spiders 204, other arthropods 85, gastropods 70, annelids 8, platyhelminthes 4, Onychophora 2, vascular plants 2112, nonvascular plants and lichens 320, and fungi 449. Three landscapes were sampled as long-term time series (>10 years). Seven hundred and eleven species are found in two or more landscapes. Consolidating the substantial amount of primary data available on biodiversity responses to fragmentation in the context of land-use change and natural disturbances is an essential part of understanding the effects of increasing anthropogenic pressures on land. The consistent format of this database facilitates testing of generalizations concerning biologic responses to fragmentation across diverse systems and taxa. It also allows the re-examination of existing datasets with alternative landscape metrics and robust statistical methods, for example, helping to address pseudo-replication problems. The database can thus help researchers in producing broad syntheses of the effects of land use. The database is dynamic and inclusive, and contributions from individual and large-scale data-collection efforts are welcome.

A new Lepidoblepharis lizard (Squamata: Sphaerodactylidae) from the Colombian Guyana shield.

Lepidoblepharis lizards are tiny geckos of the forest leaf litter. This genus is distributed from Nicaragua to the Amazonian region of Peru and Brazil, and the genus currently contains 21 species. We found a new small Lepidoblepharis from eastern Colombia that we here describe as a new species. It is characterized by having granular or subconical dorsal scales; 10-13 subdigital lamellae under 4th toe; postmental border slightly or strongly projecting backwards, followed by 2-5 (usually 3) postmentals; and 20-31 scales across snout at lst/2nd supralabial suture. This new taxon is compared to all congeners.

Rediscovery and first record of the Phantasma Tree Snake, Imantodes phantasma Myers, 1982 (Serpentes, Colubridae), in Colombia

We report the first record in Colombia, and the first find since 1966 of Imantodes phantasma Myers, 1982, based on 3 specimens from Unguía municipality, department of Chocó, Colombia. The present record adds a new snake species to the country’s list and extends this species’ documented distribution by approximately 65 km, in a straight-line northeast from its nearest previously known Panamanian locality. This is the first report of this species for more than 50 years since its description.

First record of Corallus blombergi (Rendahl & Vestergren, 1941) (Serpentes, Boidae) from Colombia

We report the first record in Colombia of Blomberg’s Tree Boa, Corallus blombergi (Rendahl & Vestergren, 1941), based on 2 specimens from Tumaco municipality, department of Nariño, Colombia. The present record extends this species’ documented distribution northwest by 55 km from its nearest previously known Ecuadorian occurrence and increases the number of Corallus species in Colombia to 5. In addition to summarizing its distribution, we present a brief comparison with the distribution of C. annulatus (Cope, 1876), the species most similar to C. blombergi.

Relaciones espaciales y alimenticias del ensamblaje de reptiles del complejo cenagoso de Zapatosa, departamento del Cesar (Colombia)

Para conocer los factores ambientales que favorece la riqueza y abundancia de especies y grupos de reptiles, su preferencia por microhabitats, dieta de especies y diferencias entre habitats en parametros como tamano de individuos, grado de deteccion y proporcion de depredacion, se realizaron salidas en areas circundantes al complejo cenagoso de Zapatosa, entre noviembre de 2006 y octubre de 2007, abarcando la epoca de lluvias y la epoca seca en cinco tipos habitats. Los habitats con diferencias significativas entre variables ambientales y estructurales fueron: bosque de ribera, palmar, sabanas arboladas y bosque casmofito; el bosque de ribera y bosque seco no resultaron diferentes. La inclinacion del terreno y el grado de intervencion antropica fueron las variables mas relacionadas con la abundancia de las especies. Al aumentar la pendiente y la intervencion antropica disminuyo la riqueza y abundancia de reptiles en general y de serpientes y lagartos; con el aumento de la temperatura media ambiental la abundancia de reptiles disminuyo. Con el aumento de la cobertura herbacea y la disminucion del diametro de los arboles, disminuyo la riqueza de lagartos y serpientes. El tamano corporal de los reptiles no fue diferente entre habitats, aunque las tallas pequenas predominaron en todos. Las serpientes presentaron menores valores de deteccion que los lagartos. El bosque de ribera presento los valores mas altos de deteccion. Un quinto de todas las lagartijas presento algun signo de depredacion y fue mas alta en el palmar. Los reptiles terrestres fueron los mas ricos y abundantes en el estudio. Los lagartos presentaron la mayor amplitud en el uso de habitat y microhabitat, mientras que las serpientes Helicops danieli y Leptodeira septentrionalis y los lagartos Anolis gaigei, Gonatodes albogularis y Cnemidophorus lemniscatus en el uso de alimento. Los lagartos exhibieron mayor solapamiento en el uso de los recursos.