Examinando por Autor "Valderrama Ardila, Carlos Humberto"

Mostrando 1 - 9 de 9

Additive partitioning of spider diversity in a fragmented tropical dry forest (Valle del Cauca, Colombia)
(American Arachnological Society, 2010-01-01) Cabra García, Jimmy
Abstract Understanding the variation of diversity patterns requires analysis at multiple spatial scales. In this study we estimated the diversity components (alpha, beta and gamma) of the spider community at El Vínculo Natural Regional Park, using the additive partitioning of diversity (species richness, Shannon's diversity index and Simpson's index) for the first time on this taxon in Colombia. We collected the specimens following a nested sampling design that consisted of two spatial scales. At the local scale, we quantified additive diversity components in 238 sampling units, and at the regional scale in five vegetation types. Total observed regional diversity (γ) was partitioned into its additive components: within sampling units (α1), among sampling units (βl) and among vegetation types (β2). We used the same approach to compare common and infrequent spider species and to compare sampling methods. A total of 1565 adult spiders and 72 identifiable juveniles, including 193 morphospecies from 36 familie.
Environmental factors associated with American cutaneous leishmaniasis in a new Andean focus in Colombia.
(2012-10-01) Valderrama Ardila, Carlos Humberto
OBJECTIVE To evaluate the environmental and ecological factors associated with Leishmania transmission and vector abundance in Chaparral, Tolima-Colombia. METHODS First, we compared the ecological characteristics, abundance of phlebotomies and potential reservoir hosts in the peridomestic environment (100 m radius) of randomly selected houses, between two townships with high and low cutaneous leishmaniasis incidence. Second, we examined peridomestic correlates of phlebotomine abundance in all 43 houses in the higher risk township. RESULTS The high transmission township had higher coverage of forest (23%vs. 8.4%) and shade coffee (30.7%vs. 11%), and less coffee monoculture (16.8%vs. 26.2%) and pasture (6.3%vs. 12.3%), compared to the low transmission township. Lutzomyia were more abundant in the high transmission township 2.5 vs. 0.2/trap/night. Lutzomyia longiflocosa was the most common species in both townships: 1021/1450 (70%) and 39/80 (49%). Numbers of potential wild mammal reservoirs were small, although four species were found to be infected with Leishmania (Viannia) spp. In the high transmission township, the overall peridomiciliary capture rate of L. longiflocosa was 1.5/trap/night, and the abundance was higher in houses located nearer to forest (ρ = -0.30, P = 0.05). CONCLUSION The findings are consistent with a domestic transmission cycle with the phlebotomies dependent on dense vegetation near the house.
Estado de fragmentación del bosque seco de la cuenca alta del río Cauca, Colombia
(Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, 2012-01-01) Valderrama Ardila, Carlos Humberto
Mediante la utilización de mapas de cobertura vegetal, fotografías aéreas y datos de campo, se evaluó el estado de fragmentación del bosque seco en la cuenca alta del río Cauca. El área de estudio, desde el norte del Cauca hasta el centro de Risaralda, abarcó una extensión de 608992 ha. Se encontró que la cobertura boscosa constituyó el 1,76% del área analizada, representada en más de 1600 fragmentos con tamaño promedio 6,03 ha. El 75% de los fragmentos se encontraron a 500 m o más de su vecino más cercano; solo nueve fragmentos tuvieron extensión mayor a 100 ha, la mayoría de forma dendrítica, con hasta 17 núcleos. Esta configuración sugiere que se comportan más como pequeños parches separados que como un solo parche grande. Se espera que el efecto de borde sea determinante en la composición de especies de bosque seco. La evaluación de la riqueza regional debe tener en cuenta la contribución de otros elementos de cobertura arbórea. Guaduales y bosques riparios son especialmente importantes ya que incrementan la conectividad del paisaje. En este contexto, cualquier iniciativa de conservación o restauración debe incluir cambios en el manejo de la matriz de caña de azúcar y pasturas para hacerla menos resistente al movimiento de organismos entre los elementos del paisaje.
Generalist Species Have a Central Role In a Highly Diverse Plant-Frugivore Network
(Blackwell Publishing Ltd, 2016-05-01) Kattán, Gustavo H.
Analysis of plant-frugivore interactions provides a quantitative framework for integrating community structure and ecosystem function in terms of how the roles and attributes of individual species contribute to network structure and resilience. In this study, we used centrality metrics to rank and detect the most important species in a mutualistic network of fruit-eating birds and plants in a cloud forest in the Colombian Andes. We identified a central core of ten bird and seven plant species in a network of 135 species that perform dual roles as local hubs and connectors. The birds were mostly large forest frugivores, such as cracids, cotingas, and toucans, which consume fruits of all sizes. The plants were species of intermediate successional stages with small- to medium-sized seeds that persist in mature forest or forest borders (e.g., Miconia, Cecropia, Ficus). We found the resilience of our network depends on super-generalist species, because their elimination makes the network more prone to disassemble than random extinctions, potentially disrupting seed-dispersal processes. At our study site, extirpation of large frugivores has already been documented, and if this continues, the network might collapse despite its high diversity. Our results suggest that generalist species play critical roles in ecosystem function and should be incorporated into conservation and monitoring programs. © 2016 The Association for Tropical Biology and Conservation.
New records and geographical distribution of ctenid spiders (Araneae: Ctenidae) in Colombia
(Magnolia Press, 2013-09-05) Simo, Miguel
This study provides new records, geographical distribution extensions and a checklist of the current ctenids species in Co-lombia based on the review of four arachnological collections and published literature. A total of 15 new records for Cteni-dae in Colombia are reported; nine of these species are new records for the country and the distribution of the remaining six is expanded. The genus Centroctenus Mello-Leitão, 1929 (C. ocelliventer Strand, 1909) is recorded for first time in Colombia and Cupiennius coccineus (F.O. Pickard-Cambridge, 1901) for South America. Due to the strategic geographic position of Colombia, which is a transition zone between Southern and Central American biotas, species inventories in different localities are important to fill distributional gaps. The number of known species of ctenids in Colombia is in-creased from 16 to 25 and these data will be useful for future studies in taxonomy, systematics and biogeography of this family.
Phlebotomine vector ecology in the domestic transmission of American cutaneous leishmaniasis in Chaparral, Colombia.
(The American Society of Tropical Medicine and Hygiene, 2011-11-01) Ocampo, Clara Beatriz
Phlebotomine vector ecology was studied in the largest recorded outbreak of American cutaneous leishmaniasis in Colombia in 2004. In two rural townships that had experienced contrasting patterns of case incidence, this study evaluated phlebotomine species composition, seasonal abundance, nocturnal activity, blood source, prevalence of Leishmania infection, and species identification. CDC miniature light traps were used to trap the phlebotomines. Traps were set indoors, peridomestically, and in woodlands. Natural infection was determined in pools by polymerase chain reaction-Southern blot, and blood sources and species identification were determined by sequencing. Large differences were observed in population abundance between the two townships evaluated. Lutzomyia longiflocosa was the most abundant species (83.1%). Abundance was higher during months with lower precipitation. Nocturnal activity was associated with human domestic activity. Blood sources identified were mainly human (85%). A high prevalence of infection was found in L. longiflocosa indoors (2.7%) and the peridomestic setting (2.5%). L. longiflocosa was responsible for domestic transmission in Chaparral.
Riqueza y composición de arañas en diferentes coberturas vegetales del Parque Natural Regional el Vínculo (Valle del Cauca, Colombia)
(Inciva, 2010-01-01-) Valderrama Ardila, Carlos Humberto; Cabra-García, Jimmy; Ulloa-Chacón, Patricia
This study aimed to estimate the spider species richness at Parque Natural Regional El Vínculo (Valle del Cauca, Colombia). We sampled spiders during day and night sessions from August to December 2008 in five vegetation types: secondary forest, riparian forest, shrubs, grassland and highly disturbed area. We used aerial and ground hand collection, beating, sorting litter and pitfall traps. We used the non-parametric richness estimators ACE, ICE, Chao 1, Chao 2, first-order Jackknife and second-order Jackknife in order to calculate the average species richness. Additionally, we calculated the average sampling efficiency. A total of 1565 adult specimen, representing 36 families and 193 morphospecies in 238 sampling units were found. The average estimated richness ranged from 46 (shrubs) to 101 (secondary forest) morphospecies. The values of average sampling efficiency ranged from 70% (secondary forest) to 90% (shrubs). The average estimated richness for the natural park was 238 morphospecies and the average sampling efficiency was 81%. Our results increases the number of families registered in the park in 14 and suggest this location as the place with more families of spiders in the Valle del Cauca.
Spatial modeling of cutaneous leishmaniasis in the Andean region of Colombia
(Fundaco Oswaldo Cruz, 2016-07-01) Pérez-Flórez, Mauricio
The objective of this research was to identify environmental risk factors for cutaneous leishmaniasis (CL) in Colombia and map high-risk municipalities. The study area was the Colombian Andean region, comprising 715 rural and urban municipalities. We used 10 years of CL surveillance: 2000-2009. We used spatial-temporal analysis - conditional autoregressive Poisson random effects modelling - in a Bayesian framework to model the dependence of municipality-level incidence on land use, climate, elevation and population density. Bivariable spatial analysis identified rainforests, forests and secondary vegetation, temperature, and annual precipitation as positively associated with CL incidence. By contrast, livestock agroecosystems and temperature seasonality were negatively associated. Multivariable analysis identified land use - rainforests and agro-livestock - and climate - temperature, rainfall and temperature seasonality - as best predictors of CL. We conclude that climate and land use can be used to identify areas at high risk of CL and that this approach is potentially applicable elsewhere in Latin America.
Wiki aves de Colombia: la primera guía virtural sobre las aves colombianas
(Asociación Colombiana de Zoología, 2010-11-03) Valderrama Ardila, Carlos Humberto
El Wiki Aves de Colombia es una herramienta de consulta con fines de investigación y educación. Su objetivo es mejorar el conocimiento y la valoración de las aves de Colombia y facilitar la integración de información y contenidos así como de las personas y organizaciones que trabajan en el tema. Los contenidos del wiki se construyen a partir de información publicada como guías de campo y artículos, así como contenidos digitales. Además de información reciente sobre la taxonomía, conservación y sitios de observación de aves, el fuerte del wiki son las especies. En el wiki cada ave contiene información básica sobre su identificación, comportamiento, distribución, hábitat, alimentación y conservación, además de links a contenidos multimedia como videos, vocalizaciones e imágenes. En su primera fase el Wiki está siendo alimentado por un pequeño grupo de personas que ingresarán contenidos y se encargarán de probar y pulir la herramienta durante el 2010.