ABSTRACT
Although habitat loss has large, consistently negative effects on biodiversity, its genetic consequences are not yet fully understood. This is because measuring the genetic consequences of habitat loss requires accounting for major methodological limitations like the confounding effect of habitat fragmentation, historical processes underpinning genetic differentiation, time-lags between the onset of disturbances and genetic outcomes, and the need for large numbers of samples, genetic markers, and replicated landscapes to ensure sufficient statistical power. In this paper we overcame all these challenges to assess the genetic consequences of extreme habitat loss driven by mining in two herbs endemic to Amazonian savannas. Relying on genotyping-by-sequencing of hundreds of individuals collected across two mining landscapes, we identified thousands of neutral and independent single-nucleotide polymorphisms (SNPs) in each species and used these to evaluate population structure, genetic diversity, and gene flow. Since open-pit mining in our study region rarely involves habitat fragmentation, we were able to assess the independent effect of habitat loss. We also accounted for the underlying population structure when assessing landscape effects on genetic diversity and gene flow, examined the sensitivity of our analyses to the resolution of spatial data, and used annual species and cross-year analyses to minimize and quantify possible time-lag effects. We found that both species are remarkably resilient, as genetic diversity and gene flow patterns were unaffected by habitat loss. Whereas historical habitat amount was found to influence inbreeding; heterozygosity and inbreeding were not affected by habitat loss in either species, and gene flow was mainly influenced by geographic distance, pre-mining land cover, and local climate. Our study demonstrates that it is not possible to generalize about the genetic consequences of habitat loss, and implies that future conservation efforts need to consider species-specific genetic information.
ABSTRACT
High-resolution satellite images, digital elevation models, bathymetric and sedimentological surveys coupled with statistical analysis were used to understand the physical environment and discuss their influence on water quality of the five upland lakes of Serra Sul dos Carajás, southeast Amazonia. The lakes have mid-altitude ranges (elevation), very small (catchment) and shallow to very shallow (central basins). Based on the length, area and volume, Violão and TI (Três Irmãs)-3 lakes may present large vertical movements of the water due to wind action and weakly stratified waters. Trophic conditions based on depth and shore development (Ld) parameters must be used with caution, since Amendoim Lake is relatively deep, but it is oligotrophic to ultra-oligotrophic. Ld values suggest that the lakes are circular to subcircular and are likely formed by solution process, as also suggested by volume development. TI-2 Lake is only presenting convex central basin and has highest dynamic ratio (DR), thus it may have high sedimentation and erosion rates. Based on the relationship between studied parameters, morphometric index and DR likely influence temperature and dissolved oxygen of waters of TI-2 Lake due to its depth profile and wind-induced surface mixing. Nevertheless, water quality parameters are controlled by catchment characteristics of the lakes.
ABSTRACT
Introducción: alteraciones de este aparato estilohioideo son frecuentes y se manifiestan por el alargamiento del proceso estiloides y también por la osificación del ligamento estilohioideo. Los cambios pueden ser asintomáticos o pueden desencadenar una serie de síntomas como el dolor en cabeza. Objetivo: determinar la prevalencia del alargamiento del proceso estiloide y de la osificación del ligamento estilohioideo en radiografías panorámicas, atendiendo a la distribución según edad, sexo y lado afectado. Métodos: se tomaron 300 radiografías panorámicas digitales de los archivos de un Servicio de Radiología Dental. Fueron seleccionadas al azar entre las realizadas en 2012, y evaluadas por un único examinador. Fueron consideradas las radiografías en las cuales el proceso estiloide del hueso temporal superaba en más de 1 cm el borde más inferior del cartílago del lóbulo de la oreja y aquellas en la que el ligamento estilohioideo aparecía radiopaco. Resultados: en este estudio, se encontraron 108 radiografías (36 por ciento) con estas condiciones. Hubo una mayor prevalencia de alargamiento del proceso estiloide y/o la osificación del ligamento estilohioideo en mujeres (63 por ciento); se presentó bilateralmente en 72 por ciento de los casos, con mayor prevalencia en el rango etario de 61 a 70 años. Conclusión: la prevalencia de alteraciones en el complejo estilohioideo en las radiografías analizadas fue de 36 por ciento, la mayoría con presentación bilateral; predominó en mujeres del grupo etario referido(AU)
Introduction: alterations of the stylohyoid chain are common, taking the shape of styloid process elongation and stylohyoid ligament ossification. Changes may either be asymptomatic or trigger a number of symptoms such as headache. Objective: determine the prevalence of styloid process elongation and stylohyoid ligament ossification in panoramic radiographs based on distribution by age, sex and affected side. Methods: examination was conducted of 300 digital panoramic radiographs from the registries of a dental radiology service. Radiographs were randomly selected from among those performed in 2012, and evaluated by a single researcher. The radiographs considered were those in which the temporal styloid process exceeded in more than 1 cm the lowermost edge of the earlobe cartilage and those in which the stylohyoid ligament was radiopaque. Results: the study found 108 radiographs (36 percent) meeting these requirements. There was a higher prevalence of styloid process elongation and/or stylohyoid ligament ossification among women (63 percent), whereas the condition was bilateral in 72 percent of the cases, with a predominance of the 61-70 age group. Conclusion: prevalence of alterations of the stylohyoid complex in the radiographs analyzed was 36 percent. Most alterations were bilateral. There was a predominance of women from the above-mentioned age group(AU)
