Browsing by Autor "Thierry Oberdorff"

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COMPARACIÓN DE LAS COMUNIDADES DE MACROINVERTEBRADOS ACUÁTICOS EN RÍOS INTERMITENTES Y PERMANENTES DEL ALTIPLANO BOLIVIANO: IMPLICACIONES PARA EL FUTURO CAMBIO CLIMÁTICO
(2009) Nabor Moya; François‐Marie Gibon; Thierry Oberdorff; Claudio Rosales; Eduardo Domínguez
El impacto de la estacionalidad de los ríos sobre las comunidades de macroinvertebrados fue estudiado en ríos de la zona Altoandina de Bolivia, durante la época de transición y época seca del año 2008. En nueve arroyos intermitentes y nueve permanentes se colectaron muestras de macroinvertebrados y parámetros ambientales. A traves de análisis multivariados, se determinaron relaciones entre variables biológicas (según riqueza, abundancia, composición trófica y rasgos biológicos) con las variables ambientales. La estacionalidad no tuvo efecto significativo sobre la riqueza ni densidad de macroinvertebrados, tampoco se encontraron efectos notorios sobre la composición trófica ni los rasgos biológicos (tipo de respiración), pero sí encontramos diferencias significativas en la composición taxonómica, especialmente en la proporción de Ephemeroptera, Plecoptera y Trichoptera (EPT); asimismo, encontramos que existen otras variables ambientales como la profundidad, solidos disueltos y pH que tienen mayor efecto que la intermitencia en la riqueza y densidad total. De acuerdo a datos climáticos de la región Andina de Bolivia se sabe que en el futuro habrá una disminución del agua, incluso la desecación temporal en varios ríos de la zona, esto debido a la disminución de los glaciares. De esta manera, el futuro cambio climático reflejado a través de la estacionalidad de los ríos, tendrá mayor efecto en los cambios de la estructura taxonómica que en la estructura funcional, lo que indica que probablemente tendrá implicaciones más fuertes en la conservación de taxa que en la composición de los rasgos de la comunidad de macroinvertebrados.
Comparison of aquatic macroinvertebrate communities from intermittent and perennial bolivian headwater andean streams: implications for future climate change
(2009) Nabor Moya; François‐Marie Gibon; Thierry Oberdorff; Claudio Rosales; Eduardo Domı́nguez
Context‐dependent resistance of freshwater invertebrate communities to drying
(Wiley, 2017) Thibault Datry; Ross Vander Vorste; Edgar Goïtia; Nabor Moya; Melina Campero; Fabiola Rodríguez; José Zubieta; Thierry Oberdorff
Abstract More freshwater ecosystems are drying in response to global change thereby posing serious threat to freshwater biota and functions. The production of desiccation‐resistant forms is an important adaptation that helps maintain biodiversity in temporary freshwaters by buffering communities from drying, but its potential to mitigate the negative effects of drying in freshwater ecosystems could vary greatly across regions and ecosystem types. We explored this context dependency by quantifying the potential contribution of desiccation‐resistance forms to invertebrate community recovery across levels of regional drying prevalence (defined as the occurrence of drying events in freshwaters in a given region) and ecosystem types (lentic, lotic) in temporary neotropical freshwaters. We first predicted that regional drying prevalence influences the selection of species with desiccation‐resistant forms from the regional species pools and thus increases the ability of communities to recover from drying. Second, we predicted lentic freshwaters harbor higher proportions of species with desiccation‐resistant forms compared to lotic, in response to contrasted hydrologic connectivity. To test these predictions, we used natural experiments to quantify the contribution of desiccation‐resistant forms to benthic invertebrate community recovery in nine intermittent streams and six geographically isolated temporary wetlands from three Bolivian regions differing in drying prevalence. The contribution of desiccation‐resistant forms to community recovery was highest where regional drying prevalence was high, suggesting the species pool was adapted to regional disturbance regimes. The contribution of desiccation‐resistant forms to community recovery was lower in streams than in wetlands, emphasizing the importance of hydrologic connectivity and associated recolonization processes from in‐stream refuges to recovery in lotic systems. In all regions, the majority of functional traits were present in desiccation‐resistant taxa indicating this adaptation may help maintain ecosystem functions by buffering communities from the loss of functional traits. Accounting for regional context and hydrologic connectivity in community recovery processes following drying can help refine predictions of freshwater biodiversity response to global change.
Convergence of temperate and tropical stream fish assemblages
(Wiley, 2009) Carla Ibañez; Jérôme Belliard; Robert M. Hughes; Pascal Irz; André Kamdem‐Toham; Nicolas Lamouroux; Pablo A. Tedesco; Thierry Oberdorff
The hypothesis of convergence takes the deterministic view that community (or assemblage) structure can be predicted from the environment, and that the environment is expected to drive evolution in a predictable direction. Here we present results of a comparative study of freshwater fish assemblages from headwater streams in four continents (Europe, North America, Africa and South America), with the general objective of testing whether these assemblages display convergent structures under comparable environmental conditions (i.e. assemblage position in the stream longitudinal continuum). We tested this hypothesis by comparing species richness and trophic guilds of those stream fish assemblages represented in available data from multiple sites on each continent. Independent of phylogenetic and historical constraints, fish assemblage richness and trophic structure in the four continents converged along the stream continua to a substantial degree. For the four continents, assemblage richness increased, the proportion of invertivorous species decreased, and the proportion of omnivorous species increased from upstream to downstream, supporting theoretical predictions of the river continuum concept. However, the herbivore/detritivore and piscivore guilds were virtually absent from our small European and North American stream sites, unlike our African and South American stream sites. This divergence can be linked to differences in energy availability between temperate and tropical systems.
Density-range size relationships in French riverine fishes
(Springer Science+Business Media, 2004) Évelyne Tales; Philippe Keith; Thierry Oberdorff
Desarrollo de un índice multimétrico basado en macroinvertebrados acuáticos para evaluar la integridad biológica en ríos de los valles interandinos de Bolivia
(LA Referencia, 2011) Nabor Moya; Eduardo Domı́nguez; Edgar Goïtia; Thierry Oberdorff
Se presenta un índice multimétrico que permite discriminar la variabilidad ambiental natural de la antropogénica en 91 sitios (63 sitios de referencia y 28 sitios perturbados) distribuidos de manera uniforme a lo largo de la cuenca alta del Río Grande (Bolivia). En este procedimiento se utilizaron inicialmente 12 métricas que reflejan distintos atributos de la estructura y el funcionamiento de la comunidad de macroinvertebrados acuáticos, por su potencial como indicadoras de alteración de ambientes acuáticos. En principio, usando los sitios de referencia, se desarrollaron modelos estadísticos que describen la respuesta de las distintas métricas a la variabilidad ambiental natural. Luego se utilizaron estos modelos para predecir la respuesta de las métricas en condiciones alteradas, para lo cual se usaron los sitios que presentaban distintos tipos de perturbación antropogénica (i.e., perturbación por actividad agrícola, urbana y minera). De las 12 métricas iniciales se conservaron sólo cinco para elaborar el índice final (riqueza total, abundancia total, riqueza de Ephemeroptera, Plecoptera y Trichoptera (EPT), porcentaje en abundancia de EPT y porcentaje en abundancia de raspadores). Estas métricas resultaron las más efectivas al responder de manera significativa al gradiente de perturbación. Este índice distinguió con claridad los sitios de referencia de los perturbados, y mostró una relación lineal negativa significativa frente a un gradiente de perturbaciones físicas y químicas. Esta aproximación puede servir como herramienta de biomonitoreo para evaluar la integridad biótica y la biodiversidad acuática en los ríos de la región de los valles interandinos de Bolivia.
Determinants of local and regional communities in intermittent and perennial headwaters of the Bolivian Amazon
(Wiley, 2016) Thibault Datry; Nabor Moya; José Zubieta; Thierry Oberdorff
Summary The effect of drying events on aquatic biodiversity is still overlooked in wet Neotropical systems. Yet, the responses of local communities and metacommunities in these biodiversity hotspots may differ from what is reported in other areas. We addressed the effect of drying events on local and regional fish and macroinvertebrate communities in the headwaters of the Chipiriri River basin, in the wet Neotropical piedmont of Bolivia. According to current knowledge in intermittent rivers and ephemeral streams (IRES) ecology, we predicted that intermittent (INT) sites would harbour lower α‐diversity, but higher β‐diversity, than perennial (PER) sites, due to local, negative effect of drying combined with the existence of multiple recovery stages at the network scale. Although habitat variables were similar between INT and PER sites, local and regional diversity patterns differed. Local invertebrate communities were not different between site types as soon as 4–6 weeks after flow resumption. The proximity of colonist sources and frequent rainfall probably enhanced persistence through dry periods and high resilience. In contrast, fish communities were still poorer at INT than PER sites, indicating they were still in the process of recolonising upstream INT reaches. β‐diversity analyses confirmed that invertebrate and fish metacommunities were not at the same recovery stage because (i) β‐diversity of invertebrates was best explained by physical and environmental distances at both INT and PER sites, whereas that of fish was explained only by physical distances at INT sites; (ii) fish β‐diversity was higher at INT than at PER sites, but invertebrate β‐diversity was similar; and (iii) physical distances were correlated with the turnover component of invertebrate β‐diversity but with the nestedness component for fish. Exploring regional community patterns in IRES and across biota with different dispersal abilities and modes can advance metacommunity theory and improve our ability to predict local community composition in dynamic ecosystems.
Dietary-morphological relationships in fish assemblages of small forested streams in the Bolivian Amazon
(EDP Sciences, 2007) Carla Ibañez; Pablo A. Tedesco; Rémy Bigorne; Bernard Hugueny; Marc Pouilly; Claudia Zepita; José Zubieta; Thierry Oberdorff
We explored the relationships between diet and morphology in 30 fish species from forested tropical streams of the Bolivian Amazon. These species were first assigned to eight broad trophic guilds based on stomach contents analysis. The relationships between diet and morphology were then examined using Redundancy Analysis, after having checked for potential phylogenetical effects. Results show that, independently of any phylogenetic constraints, some of the trophic guilds could be grossly predicted from few relevant morphological attributes (i.e. relative intestinal length, standard length and mouth orientation) and thus suggest a significant link between diet and morphology. In other words, species having similar diet tend to converge to some extent on some morphological attributes. This link was nevertheless rather weak, suggesting that even if morphology may set limits to patterns of resource use, these limits are broad enough to allow fishes changing their choice of prey resources to respond to local biotic and/or abiotic conditions.
Distribution patterns, population status and conservation of Melanosuchus niger and Caiman yacare (Crocodylia, Alligatoridae) in oxbow lakes of the Ichilo river floodplain, Bolivia
(Vicerractoría Investigación, 2007) Ximena Aguilera; Jorge S. Coronel; Thierry Oberdorff; Paul A. Van Damme
Caiman yacare (lagarto) and Melanosuchus niger (black caiman), sympatric species in the Bolivian Amazon basin, have been severely overexploited in the past. We present the results of a standardized survey of C. yacare and M. niger populations in order to evaluate their actual population status in twelve oxbow lakes of the Ichilo River floodplain. Additionally we explored the effect of environmental and anthropogenic variables on caiman distribution patterns. The average density of C yacare and M niger in the shoreline of floodplain lakes was of 6 and 1 ind/km, respectively. For both species, the population was composed mainly of juvenile individuals. We used regression tree analysis (RTA) to assess patterns of M. niger and C. yacare densities with eight environmental and two anthropogenic variables. The RTA analysis showed that the variation in the densities of both C. yacare (52.4%) and M. niger (36.8 %) was related to water conductivity. For C yacare, higher densities occurred at higher values of water conductivity, while M. niger densities followed an opposite trend, resulting in relatively well spatially segregated populations of the two species. After excluding conductivity, Lake-River Distance (LRD) was shown to be the main splitting variable in the RTA analysis. The observed distribution patterns may be the result of the historical post-hunting situation, in combination with differences in habitat selection by the two species, and competitive exclusion processes between the two species. M. niger, a species reported to be recovering slowly from previous low population levels, appears relatively well protected in the Ichilo river floodplain.
Effects of natural and anthropogenic environmental changes on riverine fish assemblages: a framework for ecological assessment of rivers
(Instituto de Tecnologia do Paraná (Tecpar), 2005) Francisco Leonardo Tejerina‐Garro; Mabel Maldonado; Carla Ibañez; Didier Pont; Nicolas Roset; Thierry Oberdorff
Freshwater is a basic need for the mankind. Effective biological tools (ecologically based, efficient, rapid and consistently applicable to different ecological regions) are needed to measure the "health" of rivers. Adapting such tools over a broad geographic area requires a detailed understanding of both the patterns of organisms assemblage composition and distribution within and among water bodies under natural conditions, and the nature of the major environmental gradients that cause or explain these patterns. A comprehensive review of the available litterature dealing with the identification of environmental factors structuring riverine fish assemblages under natural conditions permits to identify the most consistent ones.
Effects of the non-native Arapaima gigas on native fish species in Amazonian oxbow lakes (Bolivia)
(Public Library of Science, 2025) Danny Rejas; Monika Winder; Reinaldo Cholima; Thierry Oberdorff
The introduction of non-native fish species into new environments has raised global concerns due to potential ecological impacts on recipient ecosystems. A previous study focusing on the introduced fish species Arapaima gigas in Bolivian Amazon waters showed that its isotopic niche significantly overlapped with most co-occurring native fish species, suggesting potential competition. To evaluate this hypothesis, we extended here the investigation by comparing the trophic position and isotopic niche width of eleven abundant native fish species inhabiting both colonized and non-colonized floodplain lakes. We found lower trophic positions in colonized versus non-colonized lakes only for native piscivores, mostly driven by a shift towards increased dietary proportion of detritivorous fishes. Conversely, results showed that the isotopic niche width of most fish species analyzed (i.e. 10 over 11 species) did not significantly decrease in colonized compared to non-colonized lakes. Our overall results suggest potentially low competitive interactions between A. gigas and native fishes, with the notable exception of piscivorous species. We attribute our findings to the high abundance of available resources in Amazon oxbow lakes.
Environmental correlates of body size distribution in Cyprinidae (Actinopterygians) depend on phylogenetic scale
(Wiley, 2014) Gaël P.J. Denys; Pablo A. Tedesco; Thierry Oberdorff; Philippe Gaubert
Abstract The pattern of increasing species body size with increasing latitude has been noticed in different groups of animals. Here, we used seven key environmental factors and independent contrasts to assess body size latitudinal clines in Cyprinidae at two phylogenetic levels (inter‐ and intragenera), which were defined using a genus‐level supertree. Model selection procedures revealed that environmental factors shaping body size variation in Cyprinidae differed according to the phylogenetic scale considered. At the higher phylogenetic level, we found that both temperature (negative effect) and habitat availability (positive effect of drainage basin surface area) constituted mechanistic explanations of large‐scale body size distribution. No temperature‐related body size cline was observed at the intragenus level. Instead, competitive interaction (negative effect of species richness), habitat availability (positive effect of drainage basin surface area), migration ability and available energy (positive effects of glacial coverage and actual evapotranspiration) constitute alternative explanations at this lower phylogenetic scale. We conclude that (i) at the intergenus level, cyprinids do show a tendency to be smaller at high temperatures and larger at low temperatures, (ii) this tendency no longer exists at the intragenus level, (iii) latitude per se is a weak predictor of body size clines whatever the taxonomic level analysed, (iv) generalising geographical body size patterns may be rendered difficult by the superimposition of a series of mechanisms across different taxonomic scales, and (v) habitat size, here acting positively at both taxonomic scales, may play a major role in shaping riverine species body size clines.
Evidence of history in explaining diversity patterns in tropical riverine fish
(Wiley, 2005) Pablo A. Tedesco; Thierry Oberdorff; Carlos A. Lasso; Milton Zapata; Bernard Hugueny
Abstract Aim Documentation of the ongoing effect of rain forest refuges at the last glacial maximum (LGM) on patterns of tropical freshwater fish diversity. Location Tropical South and Central America, and West Africa. Methods LGM rain forest regions and species richness by drainage were compiled from published data. GIS mapping was applied to compile drainage area and contemporary primary productivity. We used multiple regression analyses, applied separately for Tropical South America, Central America and West Africa, to assess differences in species richness between drainages that were connected and disconnected to rain forest refuge zones during the LGM. Spatial autocorrelation of the residuals was tested using Moran's I statistic. We added an intercontinental comparison to our analyses to see if a historical signal would persist even when a regional historical effect (climate at the LGM) had already been accounted for. Results Both area and history (contact with LGM rain forest refuge) explained the greatest proportions of variance in the geographical pattern of riverine species richness. In the three examined regions, we found highest richness in drainages that were connected to the rain forest refuges. No significant residual spatial autocorrelation was detected after considering area, primary productivity and LGM rain forest refuges. These results show that past climatic events still affect West African and Latin American regional and continental freshwater fish richness. At the continental scale, we found South American rivers more species‐rich than expected on the basis of their area, productivity and connectedness to rain forest refuge. Conversely, Central American rivers were less species‐diverse than expected by the grouped model. African rivers were intermediate. Therefore, a historical signal persists even when a regional historical effect (climate at the LGM) had already been accounted for. Main conclusions It has been hypothesized that past climatic events have limited impact on species richness because species have tracked environmental changes through range shifts. However, when considering organisms with physically constrained dispersal (such as freshwater fish), past events leave a perceptible imprint on present species diversity. Furthermore, we considered regions that have comparable contemporary climatic and environmental characteristics, explaining the absence of a productivity effect. From the LGM to the present day (a time scale of 18,000 years), extinction processes should have played a predominant role in shaping the current diversity pattern. By contrast, the continental effects could reflect historical contingencies explained by differences in speciation and extinction rates between continents at higher time scales (millions of years).
Indice multimétrico de integridad biótica béntica para la cuenca del Río Chipiriri, Cochabamba - Bolivia
(2006) Nabor Moya; Thierry Oberdorff
MULTIMETRIC INDEX OF BIOTIC INTEGRITY BASED ON MACROINVERTEBRATES TO ASSESS BIOTIC CONDITION OF STREAMS IN THE CHIPIRIRI BASIN, COCHABAMBA - BOLIVIA Con el proposito de desarrollar un indice multimetrico para evaluar la calidad biologica de los rios de la Cuenca Chipiriri (Bolivia), tomamos muestras de macroinvertebrados bentonicos y medidas ambientales en dos grupos de sitios distribuidos uniformemente en toda la cuenca, 38 sitios con minima perturbacion antropogenica y 29 sitios perturbados. Usando los datos del primer grupo de sitios, desarrollamos modelos estadisticos sencillos de modo que expliquen adecuadamente los patrones observados de 12 diferentes variables biologicas tomadas en cuenta; posteriormente, seleccionamos las variables biologicas mas efectivas que respondieron de forma significativa a efectos de perturbacion. Finalmente, sumando los valores de las variables biologicas seleccionadas obtuvimos el indice final que distinguio claramente la variacion de la calidad biologica de las condiciones naturales y perturbadas. Los metodos y consideraciones descritas en este trabajo, podrian emplearse para desarrollar un indice de integridad ecologica en otras regiones, incluyendo nuevos parametros a esta escala. Palabras claves: Evaluacion biologica, macroinvertebrados, rios tropicales, perturbacion antropogenica, Chapare, Bolivia. ABSTRACT In order to develop a multimetric biotic integrity index, we collected data on the macroinvertebrate communities and local environmental habitat descriptors in 38 reference and 29 disturbed sites, uniformly distribute within the Chipiriri watershed (Bolivia). Using the reference data set, stepwise multiple linear regression procedures were first applied to develop the simplest possible response model that adequately explained the observed patterns of 12 different biological variables, reflecting macroinvertebrate community structure. In a second step, we selected the most effective variables that discriminate between reference and disturbed sites. Finally, adding the values of the biological variables selected, we obtained a final index score that described biotic integrity of the reference and disturbed sites as excellent, good, fair, poor, or very poor. Our final index achieved good distinction between natural and human-induced variation in biological condition. Including additional parameters, this approach could be used in the near future to develop a nation biotic integrity index. Key words: Bioassessment, macroinvertebrates, tropical streams, anthropogenic disturbance, Chapare, Bolivia.
Initial development of a multi-metric index based on aquatic macroinvertebrates to assess streams condition in the Upper Isiboro-Sécure Basin, Bolivian Amazon
(Springer Science+Business Media, 2007) Nabor Moya; Sylvie Tomanová; Thierry Oberdorff
Macroinvertebrate food web structure in a floodplain lake of the Bolivian Amazon
(Springer Science+Business Media, 2010) Carlos I. Molina; François‐Marie Gibon; Thierry Oberdorff; Eduardo Domı́nguez; Julio Pinto; Rubén Marín; Marc Roulet
Macroinvertebrate-based multimetric predictive models for evaluating the human impact on biotic condition of Bolivian streams
(Elsevier BV, 2010) Nabor Moya; Robert M. Hughes; Eduardo Domı́nguez; François‐Marie Gibon; Edgar Goïtia; Thierry Oberdorff
Metacommunity patterns across three Neotropical catchments with varying environmental harshness
(Wiley, 2016) Thibault Datry; Adriano S. Melo; Nabor Moya; José Zubieta; Evans De La Barra; Thierry Oberdorff
Summary Most metacommunity studies indicate that dispersal processes play a minor role compared with species sorting in explaining metacommunity organisation, in particular, in stream systems. However, the role of dispersal could vary with environmental harshness, as a result of frequent resetting of community succession by disturbances and the selection of generalist species from regional species pools. The importance of dispersal may also be mitigated by species dispersal ability. In this study, we explored how species sorting and dispersal shaped invertebrate and fish metacommunities across streams in three tropical headwater catchments in Bolivia with contrasting environmental harshness, including flow regime, altitude and climate conditions. We addressed the hypothesis that the relative roles of dispersal and species sorting vary with environmental harshness: we predicted that the role of species sorting would predominate in benign conditions, whereas that of dispersal would predominate under moderate environmental harshness, and that neither dispersal nor species sorting would be relevant to explain metacommunities under high environmental harshness. We also hypothesised that the role of dispersal would decrease with increasing species dispersal ability. Although there was little or no spatial autocorrelation of environmental distances (i.e. environmental differences) across the headwater catchments, community similarity correlated more strongly with environmental than spatial distances among headwater sites that had low environmental harshness, but the opposite pattern was observed among sites with moderate environmental harshness. Under high environmental harshness, neither environmental harshness nor spatial distances between sites explained community similarity. Under moderate environmental harshness, the correlation between community similarity and spatial distances was the strongest for moderate dispersers of both invertebrates and fish. Yet, in contrast to fish, strongly dispersing invertebrate taxa were spatial structured, suggesting that they were not able to reach all sites as predicted. Our results suggest the role of dispersal might be underestimated, notably in systems prone to environmental harshness. Better proxies for dispersal, along with the use of spatial distances to account for resistance to animal movements in river systems and that account for flow magnitude and directionality, slope, riparian vegetation, wind and streambed roughness, may promote a more realistic integration of dispersal processes in basic and applied metacommunity research.
Native and introduced fish species richness in French lakes: local and regional influences
(Wiley, 2004) Pascal Irz; Christine Argillier; Thierry Oberdorff
ABSTRACT Aim To analyse the importance of local and regional influences on the patterns of species richness in natural and man‐made lakes and to infer the impacts of human‐mediated introductions on these patterns. Location France. Methods Species occurrence data were gathered for 25 natural and 51 man‐made lakes. Analysis is based on regression models of local richness against their related regional richness and lake environmental variables. Results Local native richness was mostly controlled by the regional richness. Conversely, local total richness was mainly explained by local variables. These statements apply to both natural and man‐made lakes. Lacustrine systems displayed weak resistance to invaders. Main conclusions Species introductions have apparently contributed to saturate fish communities in these systems even if no clear negative effect on the survival of native species (i.e. species extinction) is detectable so far.
Opinion Paper: how vulnerable are Amazonian freshwater fishes to ongoing climate change?
(Wiley, 2015) Thierry Oberdorff; Céline Jezequel; Melina Campero; Fernando M. Carvajal‐Vallejos; J. F. Cornu; Murilo S. Dias; Fabrice Duponchelle; Javier A. Maldonado‐Ocampo; Hernán Ortega; Jean‐François Renno
With around 15% of all described freshwater fish species in the world, the Amazon Basin is by far the most fish species-rich freshwater ecosystem on the planet. In this opinion paper, a rough evaluation is given on just how vulnerable Amazonian freshwater fishes are to ongoing climate change. And to argue that current anthropogenic threats through rapid expansion of human infrastructure and economic activities in the basin could be a far greater threat to fish communities than those anticipated by any future climate change. Conservation actions in the Amazon Basin should focus preferentially on reducing the impacts of present-day anthropogenic threats.