Ecological Factors and Diversification among Neotropical Characiforms

Morphological and DNA sequence data has been used to propose hypotheses of relationships within the Characiformes with minimal comparative discussion of causes underpinning the major intraordinal diversification patterns. We explore potential primary morphological factors controlling the early diversification process in some Neotropical characiforms as the first step to identifying factors contributing to the pronounced intraordinal morphological and species diversity. A phylogenetic reconstruction based on 16S rDNA (mitochondrial) and 18S rDNA (nuclear) genes provided the framework for the identification of the main morphological differences among the Acestrorhynchidae, Anostomidae, Characidae, Ctenoluciidae, Curimatidae, Cynodontidae, Gasteropelecidae, Prochilodontidae and Serrasalmidae. Results indicate an initial split into two major groupings: (i) species with long dorsal-fin bases relative to the size of other fins (Curimatidae, Prochilodontidae, Anostomidae, Serrasalmidae) which primarily inhabit lakes, swamps, and rivers (lineage I); and (ii) species with short dorsal-fin bases (Acestrorhynchidae, Gasteropelecidae, Characidae) which primarily inhabit creeks and streams (lineage II). The second diversification stage in lineage I involved substantial morphological diversification associated with trophic niche differences among the monophyletic families which range from detritivores to large item predators. Nonmonophyly of the Characidae complicated within lineage II analyzes but yielded groupings based on differences in pectoral and anal fin sizes correlated with life style differences.España, Ministerio de Educación y Ciencia CGL2006-02155 BO

Global diversity patterns of freshwater fishes - Potential victims of their own success

Aim To examine the pattern and cumulative curve of descriptions of freshwater fishes world-wide, the geographical biases in the available information on that fauna, the relationship between species richness and geographical rarity of such fishes, as well as to assess the relative contributions of different environmental factors on these variables. Location Global. Methods MODESTR was used to summarize the geographical distribution of freshwater fish species using information available from data-based geographical records. The first-order jackknife richness estimator was used to estimate the completeness of such data in all terrestrial 1-degree cells world-wide. An a-shape procedure was used to build range maps capable of providing relatively accurate species richness and geographical rarity values for each grid cell. We also examined the explanatory capacity of a high number of environmental variables using multiple regressions and Support Vector Machine. Results Cumulative species description curves show that a high number of species of freshwater fishes remain to be discovered. Completeness values indicate that only 199 one-degree grid cells, mainly located in eastern North America and Europe, could be considered as having relatively accurate inventories. Range maps provide species richness values that are positively and significantly related to those resulting from the first-order jackknife richness estimator. The relationship between species richness and geographical rarity is triangular, so that these species-rich cells are those with a higher proportion of distributionally rare species. Species richness is predicted by climatic and/or productivity variables but geographical rarity is not. Main conclusions In general, species-rich tropical areas harbour a higher number of narrowly distributed species although comparatively species-poor subtropical cells may also contain narrowly distributed species. Historical factors may help to explain the faunistic composition of these latter areas; a supposition also supported by the low predictive capacity of climatic and productivity variables on geographical rarity values

A procedure to assess the spatial variability in the importance of abiotic factors affecting distributions: the case of world freshwater fishes

Understanding the factors shaping species' distributions is a key longstanding topic in ecology with unresolved issues. The aims were to test whether the relative contribution of abiotic factors that set the geographical range of freshwater fish species may vary spatially and/or may depend on the geographical extent that is being considered. The relative contribution of factors, to discriminate between the conditions prevailing in the area where the species is present and those existing in the considered extent, was estimated with the instability index included in the R package SPEDInstabR. We used 3 different extent sizes: 1) each river basin where the species is present (local); 2) all river basins where the species is present (regional); and 3) the whole Earth (global). We used a data set of 16,543 freshwater fish species with a total of 845,764 geographical records, together with bioclimatic and topographic variables. Factors associated with temperature and altitude show the highest relative contribution to explain the distribution of freshwater fishes at the smaller considered extent. Altitude and a mix of factors associated with temperature and precipitation were more important when using the regional extent. Factors associated with precipitation show the highest contribution when using the global extent. There was also spatial variability in the importance of factors, both between species and within species and from region to region. Factors associated with precipitation show a clear latitudinal trend of decreasing in importance toward the equator

Predicting the effects of climate change on future freshwater fish diversity at global scale

The aim of the present study was to predict future changes in biodiversity attributes (richness, rarity, heterogeneity, evenness, functional diversity and taxonomic diversity) of freshwater fish species in river basins around the world, under different climate scenarios. To do this, we use a new methodological approach implemented within the ModestR software (NOO3D) which allows estimating simple species distribution predictions for future climatic scenarios. Data from 16,825 freshwater fish species were used, representing a total of 1,464,232 occurrence records. WorldClim 1.4 variables representing average climate variables for the 1960¿1990 period, together with elevation measurements, were used as predictors in these distribution models, as well as in the selection of the most important variables that account for species distribution changes in two scenarios (Representative Concentration Pathways 4.5 and 6.0). The predictions produced suggest the extinction of almost half of current freshwater fish species in the coming decades, with a pronounced decline in tropical regions and a greater extinction likelihood for species with smaller body size and/or limited geographical ranges.We acknowledge institutional support from the Unit of Information Resources for Research at the Unit of Information Resources for Research at the "Consejo Superior de Investigaciones Científicas" (CSIC) for the article-processing charges contribution

Modestr : a software tool for studying of colombian aquatic ecosystems

ABSTRACT: The aim of this manuscript is to show the usefulness of the software package ModestR in studies of distribution of Colombian marine and freshwater species. This software is free available at the Website: . To show and test the potential of ModestR, here an exemplar assessment is presented of a database using all valid species of freshwater shes of the orders Characiformes and Siluriformes, and their geographical records available in the Global Biodiversity Information Facility (GBIF, 2012), and of the order Carcharhiniformes as representatives of marine species. ModestR includes, in its initial phase, two applications: DataManager and MapMaker. The application DataManager is designed for an integrated taxonomic information and maps of the distribution of any species group. The application MapMaker has been designed to generate species distribution maps in four different ways: 1) by importing a CSV le with the name of the species and their geographical coordinates, 2) importing the geographical records automatically from GBIF, 3) importing geographical coordinates generated by distribution models, and 4) making expert maps by selecting distribution areas, according to the types of habitats occupied by the species. The possibility of working with habitats is one of the most important contributions of ModestR and, in particular, that are mapped small lotic ecosystems (creeks, streams, etc.), large lotic ecosystems (rivers) and lentic ecosystems (ponds, lakes, reservoirs, swamps, etc.). Moreover, it is also possible to select marine and terrestrial ecosystems. Therefore, although the manuscript has been focused on species of aquatic ecosystems, ModestR also allows the same type of studies with terrestrial species.RESUMEN: El objetivo de este trabajo es mostrar las utilidades del programa informático ModestR, en estudios sobre distribución de especies en ecosistemas marinos y de agua dulce de Colombia. Este programa se encuentra disponible en la Web de manera gratuita: . Para enseñar y probar el funcionamiento de ModestR se trabajó con los datos disponibles en el Global Biodiversity Information Facility (GBIF, 2012) de los órdenes Characiformes y Siluriformes, como ejemplo de especies de peces dulciacuícolas, y del orden Carcharhiniformes de especies marinas. ModestR incluye en su fase inicial, dos aplicaciones: DataManager y MapMaker. La aplicación DataManager está diseñada para realizar manejo integrado de información taxonómica y mapas de distribución de cualquier grupo de especies. La aplicación MapMaker permite generar mapas de distribución de especies de cuatro formas diferentes: 1) importando un archivo CSV con el nombre de las especies y las coordenadas geográ cas, 2) importando los datos automáticamente del GBIF, 3) importando las coordenadas geográ cas generadas de modelos de distribución y 4) realizando mapas expertos, lo cual consiste en seleccionar las áreas de distribución, de acuerdo a los tipos de hábitats en que ocurre la o las especies en estudio. La posibilidad de trabajar con hábitats es una de las contribuciones más importantes de ModestR y, en particular, la de que los hábitats lóticos pequeños (quebradas, arroyos, etc.), los lóticos grandes (ríos) y los lenticos (lagunas, lagos, embalses, ciénagas, etc.) están cartogra ados con muy alta resolución. Además, también se diferencian los ecosistemas marino y terrestre. A pesar de que este estudio se enfocó en especies de ecosistemas acuáticos, ModestR permite también realizar el mismo tipo de ejercicios con especies terrestres

Comparative evaluation of some limnological characteristics of six lentic environments of Colombia

RESUMEN: Este estudio propuso evaluar algunas características limnológicas de seis ambientes leníticos de Colombia ubicados en un gradiente altitudinal de las regiones Caribe, Andina y Amazónica. Estos ambientes presentan diferente origen, tipo y variabilidad climática, física y química, esto es una evidencia de que en los ambientes ecuatoriales, como los de Colombia, varían entre sí y requieren un enfoque local enlazado con patrones regionales y geográficos que influencian la limnología del sistema. Los ambientes estudiados corresponden a ciénagas y lagos de inundación de tierras bajas y lagos de alta montaña, los cuales fueron monitoreados en diferentes estaciones y momentos hidrológicos; los resultados fueron analizados en torno a sus diferencias ambientales y tróficas. La ubicación altitudinal y en consecuencia el tipo, origen, morfometría y condición hidroclimática que afecta los seis sistemas promueven cambios significativos en el régimen de precipitación, la temperatura, nivel y transparencia del agua, la concentración de nutrientes, el oxígeno disuelto, el pH, la conductividad eléctrica y la clorofila a.ABSTRACT: This study proposed to evaluate some limnological characteristics of six lentic environments in Colombia located at the altitudinal gradient in Caribbean, Andean and Amazon regions. These environments have different origin, type and physic, chemic and climatic variability. This is clear evidence that equatorial environments, like the ones found in Colombia presents variation among them and requires a local approach linked with regional and geographical patterns which influences the limnology of system. The studied environments correspond to high mountain lakes and lowland floodplain, which were monitored in different hydrological seasons and times and the results were reviewed with respect to their environmental and trophic differences. Altitudinal location and therefore the type, origin, morphometry and hydroclimatic conditions which affects the six systems, promotes significant changes in the precipitation regime, temperature, level and water transparency, nutrients concentrations, dissolved oxygen, pH, electrical conductivity and chlorophyll a

Morphological traits of phytoplankton in six lentic systems of the amazonian, andean and caribbean regions of Colombia

ABSTRACT: We analyzed the morphological features of volume, maximum linear dimension, and area: volume ratio of phytoplankton assemblages of six lentic systems of different origin and morphology, including mountain lakes and oodplain lakes, all located in the Amazonian, Andean, or Caribbean regions of Colombia. In Colombia, studies of the structure of phytoplankton assemblages conducted from the viewpoint of morphological traits are scarce and those that have been conducted have favored high mountain lakes, was very few conducted in oodplain lakes. The objective of this study was to analyze the variability of morphological attributes and strategies of phytoplankton in six lentic systems. We found that in shallow, turbid, and warm environments, organisms were characterized by a high S/V, and presented mucilage and specialized traits such as agella, heterocites, and aerotopes: in contrast, in deep, clear, or lower temperature environments, phytoplankton predominated that were large and with few categorical or special traits, revealing morphological differences in assemblages of phytoplankton from systems in uenced by different sources, types, and hydroclimatology.RESUMEN: Se analizaron los rasgos morfológicos de volumen, dimensión linear máxima y relación superficie: volumen del ensamblaje toplanctónico, de seis sistemas leníticos de diferente origen y morfología, entre ellos lagos de alta montaña y lagos de inundación de tierras bajas o ciénagas, ubicados en las regiones Amazónica, Andina y Caribe de Colombia. En este país, los estudios sobre la estructura de ensamblajes toplanctónicos abordados desde el punto de vista de los rasgos morfológicos son escasos y los pocos que se han adelantado se han desarrollado en sistemas de alta montaña, siendo muy escasos los de ciénagas. El objetivo de esta investigación fue analizar la variabilidad de los atributos morfológicos y en consecuencia las estrategias del toplancton asociado a seis sistemas lénticos. Se encontró que en ambientes someros, turbios y cálidos se presentaron organismos caracterizados por una alta relación S/V, presencia de organismos con mucílago, agelos y células especializadas como aerótopos y heterocitos; en contraste, en ambientes profundos, claros y de menor temperatura predominó toplancton de mayor tamaño y con baja ocurrencia de rasgos categóricos o especiales, evidenciando diferencias morfológicas del ensamblaje del toplancton en sistemas condicionados por diferente origen, tipología e hidroclimatología

Testing of the CHEMTAX program in contrasting Neotropical lakes, lagoons, and swamps

ABSTRACT: The problem using the CHEMTAX program in freshwater environments is that the few matrices of pigment ratios available have not been tested in a wide range of environments. Sixteen Amazonian, Andean, and Caribbean lakes, lagoons, and swamps were sampled over a year. The aim was to determine if it was possible to obtain a reliable matrix of input pigment ratios that may be used in freshwater habitats with different environmental conditions. There were no clear differences among regions for most of the ratios of marker pigments to Chlorophyll a (Chl a) in most of the phytoplankton groups. Only the zeaxanthin/Chl a ratio showed clear variations among areas. The estimates for the mean relative contribution of each phytoplankton group calculated for the pigment ratios obtained in each separate habitat and season were very similar to the estimates calculated using the average pigment ratio obtained for all habitats and seasons. Our study suggests that the matrix of the average pigment ratio obtained in this study can be used to estimate phytoplankton class abundances with the CHEMTAX program in freshwater habitats with different limnological conditions

Análisis de proteinas, carbohidratos y lípidos en cladoceros y rotiferos

Seguramente, el lector lo primero que se preguntará será: ¿Por qué se ha realizado este estudio? Y también es posible que se pregunte: ¿Se puede hacer algo inédito sobre alimentación en zooplancton? En 1986 estábamos estudiando dos tipos de ecosistemas fluctuantes y eutróficos del Bajo Guadalquivir; las lagunas peridunares de Doñana y el estuario del rio. Los cladóceros y los rotíferos eran los grupos dominantes en la zona dulce del estuario y en las lagunas. En ambos sistemas observamos cómo estos grupos estaban afectados en mayor medida por dos factores, la salinidad y la temperatura. Su influencia se veía claramente ya que, todas las especies tenían unos umbrales máximos y mínimos de temperatura y salinidad. Ahora bien, los resultados indicaban la existencia de un tercer factor no menos importante: La alimentación, que tenía un efecto decisivo en la composición de las comunidades. Observamos también, que cambios en el estado trófico el medio, podían dar lugar a variaciones importantes en las poblaciones como por ejemplo: La sustitución de unas especies por otras; descenso en la densidad de la población de unas especies y aumento en las de otras, etc. Sin embargo, no fue tan fácil de dilucidar, como en el caso de los otros parámetros, cuáles eran exactamente los cambios que se estaban produciendo y como estaban afectando a las especies. Existen muchos trabajos que podrían ser usados para comprender estos fenómenos, pero la inmensa mayoría presentan el problema de que son estudios muy concretos y, además, realizados en condiciones fijadas en el laboratorio. Al llegar al convencimiento, de que este era un tema importante para poder llegar a conocer la dinámica de las especies en estos ecosistemas, decidimos comenzar su estudio. Dentro de la alimentación, existen muchas posibles líneas de trabajo. La

Immunological methods for the detection of toxic phytoplankton in the Galician coast

Poster.-- 4th International Conference on Molluscan Shellfish Safety, Santiago de Compostela, Spain, June 4-8, 2002N