18 research outputs found
Análisis de la distribución de las especies de peces de agua dulce a diferentes escalas espaciales y temporales
Cuenta con figuras, mapas, diagramas de distribución de datos a color.El presente estudio se fundamenta en que la ubicación espacial de una especie está
determinada por la distribución de la población, la cual se relaciona directamente con la
existencia de condiciones ambientales adecuadas. La tesis propone un estudio espacial y
temporal diverso, en el primer capítulo se trabajará la importancia que tienen los factores
ambientales en la ubicación espacial de los peces, para ello se planteó un análisis de tipo
pluriescalar, en el segundo capítulo se predecirán los efectos del cambio climático en la
distribución de las especies de peces a una escala mundial, mediante el uso del nicho de
ocurrencia (NOO3D) y en el tercer capítulo se realizará un estudio de caso a escala de la
cuenca amazónica, cuyo objetivo es estimar la riqueza de especies de peces más probable
presente a nivel de subcuenca, a partir de la fusión de los modelos de distribución de especies
(MDE). La contribución de las variables ambientales (bioclimáticas) cambió espacialmente
y en función de la extensión considerada, siendo la temperatura, la altitud y la precipitación,
las variables más importantes. Las predicciones mostraron que casi la mitad de las especies
de peces de agua dulce actuales se perderán en las próximas décadas, con una pronunciada
disminución en las áreas tropicales y mayores tasas de extinción en aquellas especies con un
tamaño de cuerpo y un tamaño de rango geográfico más pequeño. La estimación de la riqueza
por subcuenca del presente estudio evidenció el subregistro que presenta la cuenca del
AmazonasThe present study is based on the fact that the spatial location of a species is determined by
the population distribution, which is directly related to the existence of adequate
environmental conditions. The thesis proposes a diverse spatial and temporal study, in the
first chapter we will work in the importance of environmental factors in the spatial location
of fish, for this a multiscale analysis was proposed, in the second chapter will be predicted
the effects of the climate change in the distribution of fish species on a global scale, through
the use of the niche of occurrence (NOO3D) and in the third chapter a case study will be
carried out at the scale of the Amazon basin, whose objective is to estimate the richness of
fish species most likely present at the sub-basin level, based on the fusion of the species
distribution models (SDM). The contribution of environmental variables (bioclimatic)
changed spatially and depending on the extension considered, with temperature, altitude and
precipitation being the most important variables. Predictions showed that nearly half of the
freshwater fish species would be lost in the coming decades, with a steep decline in tropical
areas and higher extinction rates in those species with a body size and geographic range size
smaller. The estimation of the richness by sub-basin of the present study evidenced the
underreporting of the Amazon basinDoctoradoDoctor en Estudios Amazónico
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
Los macroinvertebrados bentónicos de pozo azul (cuenca del río gaira, colombia) y su relación con la calidad del agua
En julio de 2002 se realizó el estudio de algunos parámetros fisicoquímicos y la estructura de la comunidad de macroinvertebrados bentónicos asociados a cuatro coriotipos (piedra, hojarasca, sedimento y macrófitas) en el sector de Pozo Azul sobre la cuenca del río Gaira (Magdalena, Colombia). Se discute la relación entre la estructura de la comunidad y la calidad del agua del sector. Los parámetros fisicoquímicos estuvieron determinados en gran medida por las características geográficas del sistema. El agua se caracterizó por estar saturada de oxígeno y por la ausencia de compuestos intermedios de la estabilización de la materia orgánica como nitritos y amonio. Se colectaron 588 individuos distribuidos en 11 órdenes y 38 familias. Los órdenes más representativos fueron Trichoptera, Coleoptera, Diptera y Ephemeroptera, siendo el último de ellos el más abundante. Las familias más representativas fueron Baetidae, Simullidae, Perlidae, Chironomidae e Hydropsychidae, en ese mismo orden de abundancia. Para la relación de la estructura de la comunidad con la calidad del agua se calculó el índice BMWP, adaptado por la Universidad del Valle, Cali, Colombia, que estableció para este caso un agua de óptima calidad y oligosapróbita, según la ecología sapróbita, estado alcanzado luego de la estabilización frente a pequeñas alteraciones inducidas por las actividades del cultivo del café en la zona.On July 2002, a study of some physicochemical parameters and their relationship with the benthonic macroinvertebrates community structure on four coriotypes: stone, trash, silt and macrophytes, was carried out in Pozo Azul (Gaira River basin, Magdalena, Colombia). The physicochemical parameters were determined, to a considerable extent, by the geographic characteristics of the system. The water was found to be oxygen saturated, and intermediate compounds of the organic matter stabilization, such as nitrites and ammonium, there were found 588 individuals distributed in 11 orders and 38 families. The most representative orders were Trichoptera, Coleoptera, Diptera and Ephemeroptera. The most representative families were Baetidae, Simullidae, Perlidae, Chironomidae, and Hydropsychidae, in this rank of abundance. The BMWP index for the relationship between the community structure and the water quality (adapted by Universidad del Valle, Cali, Colombia) was calculated. According to this index the water quality was optimum. Also, given the general characteristics of the site studied, the water mass quality was classified as good and oligosaprobit, based on the saprobit ecology. It is possible that this state was reached due to stabilization after a small perturbation induced by coffee cultivation in the zone
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
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 differencesThis study was supported by the AMAPEZ project (CGL2006-02155 BOS) of the MEC (Ministry of Education and Science) under FEDER funds from the XUNTA de Galicia and by contributions from the Universidad de Vigo, the Universidad de Antioquia, and the Universidad Nacional de Colombia. A. Manjarrés-Hernández gratefully acknowledges a grant from COLCIENCIASS
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
Identification of species of the order characteristics in two colombian basins (amazonas and magdalena) through a statistical classification methodology.
Contiene mapas, graficas, figuras, tablas taxonómicas e imágenes de peces a color.Objetivo general : Obtener información de peces que contribuya a desarrollar un sistema experto, el cual basado en medidas morfométricas, identifique taxonómicamente algunas de las especies del orden Characiformes en dos cuencas colombianas (Amazonas y Magdalena).
Objetivos específicos:
1. Establecer posibles relaciones entre la riqueza y la distribución de los Characiformes Neotropicales.
2. Determinar cuáles son las medidas morfológicas más importantes en el proceso de diversificación del orden Characiformes y, por tanto, que permitan una mejor diferenciación de las familias, géneros y especies del orden con el método estadístico seleccionado.
3. Mejorar los algoritmos de aprendizaje del sistema experto por medio de la comprobación de la capacidad de identificación de las especies.
4. Favorecer el proceso de búsqueda de las especies de Characiformes por medio del ingreso de los nombres comunes y/o sinónimos en la base de datos del sistema experto.
5. Elaborar las fichas de identificación de las especies por medio de fotos descriptivas y sus mapas de distribución, para complementar el proceso de identificación automatizadoMaestríaMagíster en Estudios AmazónicosEcosistemas, Biodiversidad y Conservació
The Benthonic Macroinvertebrates of Pozo Azul (Gaira River Basin, Colombia) and their Relationship with Water Quality
On July 2002, a study of some physicochemical parameters and their relationship with the benthonic macroinvertebrates community structure on four coriotypes: stone, trash, silt and macrophytes, was carried out in Pozo Azul (Gaira River basin, Magdalena, Colombia). The physicochemical parameters were determined, to a considerable extent, by the geographic characteristics of the system. The water was found to be oxygen saturated, and intermediate compounds of the organic matter stabilization, such as nitrites and ammonium, there were found 588 individuals distributed in 11 orders and 38 families. The most representative orders were Trichoptera, Coleoptera, Diptera and Ephemeroptera. The most representative families were Baetidae, Simullidae, Perlidae, Chironomidae, and Hydropsychidae, in this rank of abundance. The BMWP index for the relationship between the community structure and the water quality (adapted by Universidad del Valle, Cali, Colombia) was calculated. According to this index the water quality was optimum. Also, given the general characteristics of the site studied, the water mass quality was classified as good and oligosaprobit, based on the saprobit ecology. It is possible that this state was reached due to stabilization after a small perturbation induced by coffee cultivation in the zone