Understanding the relationship between dispersal and range size.

The drivers of variability in species range sizes remain an outstanding enigma in ecology. The theoretical expectation of a positive dispersal-range size relationship has received mixed empirical support, despite dispersal being one of the most prominent hypothesised predictors of range size. Here, we synthesised results from 86 studies examining the dispersal-range size relationship for plants and animals in marine, terrestrial and freshwater realms. Overall, our meta-analysis showed that dispersal positively affects range size, but its effect is dependent on the clade and dispersal proxy studied. Moreover, despite potential differences in habitat connectivity, we did not find an effect of realm on the dispersal-range size relationship. Finally, the strength of the dispersal-range size relationship was dependent on latitude, range size metric and the taxonomic breadth of the study clade. Our synthesis emphasizes the importance of developing a mechanistic understanding of the trait to dispersal to range size relationship, considering the complexity of dispersal departure, transfer and settlement, as well as evolutionary components such as time for range expansion, speciation and past geological-environmental dynamics. We, therefore, call for a more integrative view of the dispersal process and its causal relationship with range size.

The Demographic Consequences of Adaptation: Evidence from Experimental Evolution.

AbstractThe process of adaptation toward novel environments is directly connected to the acquisition of higher fitness relative to others. Such increased fitness is obtained by changes in life history traits that may directly impact population dynamics. From a functional perspective, increased fitness can be achieved through higher resource use or more efficient resource use, each potentially having its own impact on population dynamics. In the first case, adaptation is expected to directly translate into higher population growth. In the second case, adaptation requires less energy and hence may lead to higher carrying capacity. Adaptation may thus lead to changes in ecological dynamics and vice versa. Here, by using a combination of evolutionary experiments with spider mites and a population dynamic model, we investigate how an increase in fecundity (a validated proxy for adaptation) affects a population's ecological dynamics. Our results show that adaptation can positively affect population growth rate and either positively or negatively affect carrying capacity, depending on the ecological condition leading to variation in adaptation. These findings show the importance of evolution for population dynamics in changing environments, which may ultimately affect the stability and resilience of populations.

Plant traits alone are poor predictors of ecosystem properties and long-term ecosystem functioning.

Earth is home to over 350,000 vascular plant species that differ in their traits in innumerable ways. A key challenge is to predict how natural or anthropogenically driven changes in the identity, abundance and diversity of co-occurring plant species drive important ecosystem-level properties such as biomass production or carbon storage. Here, we analyse the extent to which 42 different ecosystem properties can be predicted by 41 plant traits in 78 experimentally manipulated grassland plots over 10 years. Despite the unprecedented number of traits analysed, the average percentage of variation in ecosystem properties jointly explained was only moderate (32.6%) within individual years, and even much lower (12.7%) across years. Most other studies linking ecosystem properties to plant traits analysed no more than six traits and, when including only six traits in our analysis, the average percentage of variation explained in across-year levels of ecosystem properties dropped to 4.8%. Furthermore, we found on average only 12.2% overlap in significant predictors among ecosystem properties, indicating that a small set of key traits able to explain multiple ecosystem properties does not exist. Our results therefore suggest that there are specific limits to the extent to which traits per se can predict the long-term functional consequences of biodiversity change, so that data on additional drivers, such as interacting abiotic factors, may be required to improve predictions of ecosystem property levels.

Incomplete datasets obscure associations between traits affecting dispersal ability and geographic range size of reef fishes in the Tropical Eastern Pacific.

Dispersal is thought to be an important process determining range size, especially for species in highly spatially structured habitats, such as tropical reef fishes. Despite intensive research efforts, there is conflicting evidence about the role of dispersal in determining range size. We hypothesize that traits related to dispersal drive range sizes, but that complete and comprehensive datasets are essential for detecting relationships between species' dispersal ability and range size. We investigate the roles of six traits affecting several stages of dispersal (adult mobility, spawning mode, pelagic larval duration (PLD), body size, aggregation behavior, and circadian activity), in explaining range size variation of reef fishes in the Tropical Eastern Pacific (TEP). All traits, except for PLD (148 species), had data for all 497 species in the region. Using a series of statistical models, we investigated which traits were associated with large range sizes, when analyzing all TEP species or only species with PLD data. Furthermore, using null models, we analyzed whether the PLD-subset is representative of the regional species pool. Several traits affecting dispersal ability were strongly associated with range size, although these relationships could not be detected when using the PLD-subset. Pelagic spawners (allowing for passive egg dispersal) had on average 56% larger range sizes than nonpelagic spawners. Species with medium or high adult mobility had on average a 25% or 33% larger range, respectively, than species with low mobility. Null models showed that the PLD-subset was nonrepresentative of the regional species pool, explaining why model outcomes using the PLD-subset differed from the ones based on the complete dataset. Our results show that in the TEP, traits affecting dispersal ability are important in explaining range size variation. Using a regionally complete dataset was crucial for detecting the theoretically expected, but so far empirically unresolved, relationship between dispersal and range size.

Reconstrucción plantar con matriz de regeneración dérmica (Integra®) en paciente quemado eléctrico: presentación de un caso y revisión de la literatura / Plantar reconstruction with matrix of dermal regeneration (Integra®) in an electric burned patient: case report and literature review

Resumen Introducción: Las lesiones complejas de la cara plantar del pie son de difícil manejo desde el punto de vista reconstructivo. En la literatura el tratamiento de elección es la cobertura mediante colgajos libres. Nuestro objetivo es presentar el caso de un paciente con una lesión plantar compleja, exitosamente resuelta con el uso de matriz de regeneración dérmica (Integra®) e injerto dermoepidérmico. Caso clínico: Hombre de 35 años, que sufre quemadura eléctrica de alta tensión con lesión compleja plantar bilateral. Se manejó con escarectomías sucesivas hasta delimitar el daño tisular, y posterior cobertura con Integra® e injerto con resultado estético y funcional óptimo. Discusión: Aunque los colgajos libres son la elección en el tratamiento de esta zona anatómica, infrecuentemente son la única alternativa de reconstrucción en el paciente quemado. No hay mayor evidencia en la literatura en el uso de matrices dérmicas para la cobertura de este tipo de lesiones. Conclusión: Los autores consideran que el manejo de lesiones plantares complejas mediante el uso de matrices de regeneración dérmica es una alternativa válida a considerar en situaciones en que, por diversos motivos, no se puede ofrecer un colgajo libre.

Abstract Introduction: Complex wounds of the plantar aspect of the foot are difficult to manage in the reconstructive point of view. The standard of treatment is covering the defect with free flaps. Our goal is to present the case of a patient successfully treated with the use of matrix dermal regenaration Integra® and dermoepidermal graft for a complex plantar lesion. Clinical case: Thirty-five year old man, who suffers from high voltage electrical burn with bilateral plantar complex injury. It was handled with successive escharectomies to delimit tissue damage and subsequent coverage with Integra® and grafting with optimal aesthetic and functional results. Discussion: Although free flaps are the choice in the treatment of this anatomical area, they are infrequently the only reconstructive option in burned patients. There is no greater evidence in the literature on the use of dermal matrices to cover such injuries. Conclusion: The authors believe that the management of complex footpad lesions using dermal regeneration matrices are a valid alternative to consider in situations where for various reasons, free flaps can't be offered.

Community assembly in Lake Tanganyika cichlid fish: quantifying the contributions of both niche-based and neutral processes.

The cichlid family features some of the most spectacular examples of adaptive radiation. Evolutionary studies have highlighted the importance of both trophic adaptation and sexual selection in cichlid speciation. However, it is poorly understood what processes drive the composition and diversity of local cichlid species assemblages on relatively short, ecological timescales. Here, we investigate the relative importance of niche-based and neutral processes in determining the composition and diversity of cichlid communities inhabiting various environmental conditions in the littoral zone of Lake Tanganyika, Zambia. We collected data on cichlid abundance, morphometrics, and local environments. We analyzed relationships between mean trait values, community composition, and environmental variation, and used a recently developed modeling technique (STEPCAM) to estimate the contributions of niche-based and neutral processes to community assembly. Contrary to our expectations, our results show that stochastic processes, and not niche-based processes, were responsible for the majority of cichlid community assembly. We also found that the relative importance of niche-based and neutral processes was constant across environments. However, we found significant relationships between environmental variation, community trait means, and community composition. These relationships were caused by niche-based processes, as they disappeared in simulated, purely neutrally assembled communities. Importantly, these results can potentially reconcile seemingly contrasting findings in the literature about the importance of either niche-based or neutral-based processes in community assembly, as we show that significant trait relationships can already be found in nearly (but not completely) neutrally assembled communities; that is, even a small deviation from neutrality can have major effects on community patterns.

Experimental evidence for inherent Lévy search behaviour in foraging animals.

Recently, Lévy walks have been put forward as a new paradigm for animal search and many cases have been made for its presence in nature. However, it remains debated whether Lévy walks are an inherent behavioural strategy or emerge from the animal reacting to its habitat. Here, we demonstrate signatures of Lévy behaviour in the search movement of mud snails (Hydrobia ulvae) based on a novel, direct assessment of movement properties in an experimental set-up using different food distributions. Our experimental data uncovered clusters of small movement steps alternating with long moves independent of food encounter and landscape complexity. Moreover, size distributions of these clusters followed truncated power laws. These two findings are characteristic signatures of mechanisms underlying inherent Lévy-like movement. Thus, our study provides clear experimental evidence that such multi-scale movement is an inherent behaviour rather than resulting from the animal interacting with its environment.

A comparison of visual and collection-based methods for assessing community structure of coral reef fishes in the Tropical Eastern Pacific / Una comparación de métodos visuales y basados ​​en colecciones para evaluar la estructura de la comunidad de peces de arrecifes de coral en el Pacífico Oriental Tropical

Gorgona Island, the major insular area in the Colombian Pacific Ocean, is characterized by a remarkably high biological and ecosystem diversity for this area of the world. Coral reefs are well developed and their fish communities have been described using conventional visual surveys. These methods, however, are known to be biased towards detecting larger and more mobile species, tending to ignore small and cryptobenthic species. The two main objectives of this study were to describe the assemblage structure of the cryptobenthic fish fauna and estimate the extent to which this fauna is underestimated by visual surveys.At the beginning and the end of the warm season, we compared the cryptobenthic fish assemblage recorded using visual surveys against the one recorded using “enclosed anesthetic/rotenone samples” on isolated coral colonies (N=54 beginning of warm season; N=17 end of warm season). The crypthobenthic fish fauna associated to coral colonies was characterized by small body sizes and was composed mainly by species of the families Antennaridae, Blennidae, Gobiidae, Labrisomidae, Muraenidae, Serranidae, Scorpaenidae and Syngnathidae. Conventional visual surveys underestimated overall species richness by 28-36% and number of individuals by 16-35%. Noteworthy, four species recorded during this study using “enclosed anesthetic/rotenone samples” were new records for Gorgona Island. Although both sampling methods can detect a largely overlapping group of species, the “enclosed anesthetic/rotenone samples” method was able to detect more individuals and species, including several species that visual surveys fail to detect. Although this study is the first effort to describe the cryptobenthic fish assemblage associated to coral reefs in the Tropical Eastern Pacific, our results suggest that these assemblages are an important component of the reef fish community in the region in terms of biodiversity and functional roles. Rev. Biol. Trop. 62 (Suppl. 1): 359-371. Epub 2014 February 01.

Métodos de muestreo convencionales (censos visuales) usados en el estudio de peces arrecifales han llevado a una constante subestimación de la riqueza de especies, ya que estos tienden a ignorar especies pequeñas y crípticas. En este estudio describimos la estructura del ensamblaje de peces criptobentónicos en Isla Gorgona, Colombia y estimamos el grado en que este ensamblaje es subestimado al usar censos visuales. Al comienzo y al final de la estación cálida comparamos la capacidad de detección de censos visuales vs “muestreos cerrados con anestésico/rotenona” (N=54 comienzo; N=17 final). La fauna criptobentónica se caracterizó por mantener individuos de tamaños corporales pequeños, pertenecientes principalmente a las familias Antennaridae, Blennidae, Gobiidae, Labrisomidae, Muraenidae, Serranidae, Scorpaenidae and Syngnathidae. Los censos visuales subestimaron la riqueza de especies en un 28-36% y el número de individuos en un 16-35%. Aunque un gran número de especies son detectadas usando ambos métodos, los “muestreos cerrados con anestésico/rotenona” detectan un mayor rango de especies. Este estudio, el primer esfuerzo para describir el ensamblaje de peces criptobentónicos asociados a arrecifes coralinos en Colombia, sugiere que la fauna criptobentónica puede ser un componente importante de la comunidad arrecifal en términos de biodiversidad y papel funcional.

Evaluation of the inorganic selenium biotransformation in selenium-enriched yogurt by HPLC-ICP-MS.

Selenium is an essential element in the human diet. Interestingly, there has been an increased consumption of dietary supplements containing this element in the form of either inorganic or organic compounds. The effect of using selenium as a dietary supplement in yogurt has been evaluated. For this purpose, different concentrations of inorganic Se (ranging from 0.2 to 5000 microg g(-1)) have been added to milk before the fermentation process. Biotransformation of inorganic Se into organic species has been carefully evaluated by ion-exchange, reversed-phase, or size-exclusion chromatography, coupled to inductively coupled plasma mass spectrometry (ICP-MS). Yogurt fermentation in the presence of up to 2 microg g(-1) of Se(IV) produces a complete incorporation of this element into proteins as has been demonstrated applying a dialysis procedure. Analysis by SEC-ICP-MS showed that most of them have a molecular mass in the range of 30-70 kDa. Species determination after enzymatic hydrolysis has allowed the identification of Se-cystine using two different chromatographic systems. The biotransformation process that takes place during yogurt fermentation is very attractive because yogurt can act as a source of selenium supplementation.

Presencia de vectores de leishmaniosis cutánea y visceral en la Isla de Santa Cruz de Mompóx, Departamento de Bolívar, Colombia / Vectors of cutaneous and visceral leishmaniosis in Snata Cruz de Mompox island, Bolivar, Colombia

Se realizó una prospección entomológica en la Isla de Santa Cruz de Mompóx entre los días 23 y 29 de diciembre de 1993, con el fin de determinar si se trata de una zona de riesgo potencial de infección por Leishmania; para ello se practicaron capturas de flebotomíneos en sitios de reposo diurno y con trampas de luz tipo CDC y Shannon, colocadas simultáneamente en el peri y el extradomicilio. Se colectaron 367 ejemplares de flebotomíneos cuya Identificación demostró por primera vez la presencia en la Isla de siete especies de Lutzomyia entre las cuales se encuentran Lu. panamensis y Lu. gomezi, vectoras de leishmaniosis cutánea y Lu. evansi vectora principal de la forma visceral en la Costa Caribe Colombiana; el hallazgo demuestra que la Isla es una zona de riesgo potencial para leishmanlosis cutánea y visceral

Se realizó una prospección entomológica en la Isla de Santa Cruz de Mompox entre los días 23 y 29 de diciembre de 1993, con el fin de determinar si se trata de una zona de riesgo potencial de Infección por Leishmania; para ello se practicaron capturas de flebotomíneos en sitios de reposo diurno y con trampas de luz tipo CDC y Shannon, colocadas simultáneamente en el peri y el extradomicilio. Se colectaron 367 ejemplares de flebotomíneos cuya Identificación demostró por primera vez la presencia en la Isla de siete especies de Lutzomyia entre las cuales se encuentran Lu. panamensis y Lu. gomezi, vectoras de leishmaniosis cutánea y Lu. evansi vectora principal de la forma visceral en la Costa Caribe Colombiana; el hallazgo demuestra que la isla es una zona de riesgo potencial para leishmaniosis cutánea y visceral