Evaluación de la calidad de agua a través de macroinvertebrados bentónicos e índices biológicos en ríos tropicales en bosque de neblina montano

Los efectos de la contaminación en ríos de zonas temperadas han sido descritos de manera extensa y desde hace varias décadas, mientras existe escasa información de estos efectos en ríos neotropicales. Los macroinvertebrados bentónicos son muy utilizados como bioindicadores de la calidad de fuentes de agua, debido a sus características y requerimientos especiales que hacen a estos organismos muy sensibles a diversos impactos. Se realizó un muestreo de macroinvertebrados bentónicos en los ríos Guajalito, Palmeras y Brincador, los cuales cruzan a través del Bosque Protector Río Guajalito, con el fin de estimar la calidad de las aguas de los mismos y de comparar diversos índices biológicos de calidad de aguas (BMWP, IBMWP, BMWP/Col e índice de Sensibilidad). Además se realizó una caracterización física y química para validar la información biológica obtenida. Las familias más representativas fueron Hydropsychidae, Chironomidae y Helicopsychidae. Se encontraron diferencias significativas en la diversidad y riqueza de invertebrados bentónicos entre los diferentes ríos, y además en las puntuaciones de los diferentes índices biológicos de calidad del agua. El análisis de los diferentes parámetros (físico- químico y biológico) en estos ríos sugieren que los ríos Guajalito y Palmeras tienen aguas ligera a moderadamente contaminadas y que el río Brincador tiene un calidad óptima de sus aguas. Además, el presente estudio sugiere que el índice biológico que explica mejor sobre la calidad de las aguas en este bosque montano, es posiblemente el BMWP/Col, debido principalmente a que más del 97% de familias de invertebrados encontradas están presentes en el índice. A futuro, es necesario el desarrollo de un índice de calidad biológica para el Ecuador, donde se cubra todo el rango altitudinal y ecosistémico del país, así como las familias de macroinvertebrados comunes en los cuerpos de agua

Sexual conflict and the evolution of monandry: the case of the damselfly Ischnura hastata (Odonata: Coenagrionidae) in the Galápagos Islands

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUG1. Sexual selection favours the evolution and maintenance of polygamy, which is the dominant reproductive strategy in insects. Monogamy can evolve in very short-lived species due to time constraints. Here we study adult activity and mating behaviour of a population of the damselfly Ischnura hastata, a species rarely seen mating, and which has been suggested to be monandric, in wetlands of Isabela Island, Galápagos. 2. By means of mark-recapture methods we estimated that the daily survival rate was low, ranging from 0.385 to 0.876, yielding average life expectancies of mature individuals of only 1.2-3.2 days. Adults showed very low activity before 7:00, indicating that mating does not occur early. The number of male-female interactions and mating attempts was extremely low, with only 44 copulations recorded on over 230 h of observations. 3. Copulations were brief, with a mean duration of 11 minutes (but only two observed from the start). Males showed clear preference to attempt to grasp in tandem females of intermediate age (in 94.3% of cases), rather than young (31.3%) or mature females (24.0%). Males were very persistent once a tandem was achieved, retaining females for up to 139 min, but most females resisted and did not copulate. 4. We conclude that females of I. hastata show a very short time window to mate, exactly when they change colour from juvenile to mature, and live only enough to mate once. Short lifespan has selected for female monandry in I. hastata, creating an intense sexual conflict over mating rates.Ministerio de Economía y Competitividad | Ref. CGL2014-53140-PAgencia Estatal de Investigación | Ref. PGC2018-096656-B-I0

Fragmentation of Andes-to-Amazon connectivity by hydropower dams

Andes-to-Amazon river connectivity controls numerous natural and human systems in the greater Amazon. However, it is being rapidly altered by a wave of new hydropower development, the impacts of which have been previously underestimated. We document 142 dams existing or under construction and 160 proposed dams for rivers draining the Andean headwaters of the Amazon. Existing dams have fragmented the tributary networks of six of eight major Andean Amazon river basins. Proposed dams could result in significant losses in river connectivity in river mainstems of five of eight major systems—the Napo, Marañón, Ucayali, Beni, and Mamoré. With a newly reported 671 freshwater fish species inhabiting the Andean headwaters of the Amazon (>500 m), dams threaten previously unrecognized biodiversity, particularly among endemic and migratory species. Because Andean rivers contribute most of the sediment in the mainstem Amazon, losses in river connectivity translate to drastic alteration of river channel and floodplain geomorphology and associated ecosystem services

Biomonitoreo en ríos de Argentina: un camino por recorrer

Se describe la secuencia histórica de la aplicación de organismos acuáticos bioindicadores en la Argentina y sus posibilidades de ser difundidos e incorporados como herramientas de biomonitoreo en la gestión ambiental. En paralelo se presenta el desarrollo y las etapas acaecidas en Ecuador y en España. Tanto las distintas regiones de Argentina, como los países mencionados han seguido trayectorias semejantes, aplicando primero índices utilizados en otros países y posteriormente adaptando los mismos a la flora y fauna local, o bien reformulándolos para cada uno de los paisajes. Los índices aplicados dependieron de cada eco región y del impacto que se pretendía evaluar. La transferencia a la gestión se realizó en todos los casos de un modo lento y no regular o planificado excepto en el caso que existiera alguna normativa que obligara a su aplicación. Se concluye que en Argentina existen en la actualidad numerosos grupos con experticia en el empleo de bioindicadores en ambientes fluviales, pero hay una falencia a nivel de normativas que hace que su incorporación al monitoreo sea lento, optativo y poco comparativo entre cuencas. De la experiencia de otros países se desprende que sería necesaria la aplicación de normas específicas. Como no es posible desarrollar un único índice para todo el país, se torna indispensable establecer sistemas de inter calibración y comparación entre los distintos índices empleados para lograr una evaluación estandarizada. En ese sentido la red REM_AQUA podría contribuir a diseñar, realizar y difundir este tipo de comparaciones.We describe the historic sequence of the application of aquatic bioindicators in Argentina and the feasibility for being disseminated and incorporated as biomonitoring tools in environmental management. In parallel, we present the development and stages followed in Ecuador and Spain. Indices from other countries were first applied, and these were later adapted to the local flora and fauna or reformulated different ecoregions. The indices applied depended on each ecoregion and on the impact to evaluate. The transfer to management was carried out in all cases in a slow and not regular or planned way, except when there were some regulations that forced its application. We conclude that, currently, there are numerous groups in Argentina with expertise in the use of bioindicators in riverine environments. Still, there is a weakness at the regulatory level that makes their incorporation to monitoring studies slow, optional, and not comparative between basins. From the experience of other countries, it appears that the application of specific standards would be necessary. As it is not possible to develop a single index, it becomes essential to establish inter-calibration and inter-comparison procedures among different indices applied to standardize the evaluation at the whole country level. In this sense, the REM AQUA network may contribute to design, apply and disseminate this type of comparison.Fil: Dominguez, Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; ArgentinaFil: Encalada, Andrea C.. Universidad San Francisco de Quito; EcuadorFil: Fernandez, Hugo Rafael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; ArgentinaFil: Giorgi, Adonis David Nazareno. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Universidad Nacional de Luján. Instituto de Ecología y Desarrollo Sustentable; ArgentinaFil: Marchese Garello, Mercedes Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Miserendino, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; ArgentinaFil: Munne, Antoni. Agencia Catalana del Agua; EspañaFil: Prat, Narcís. Universidad de Barcelona; EspañaFil: Ríos Touma, Blanca. Universidad de Las Américas; EcuadorFil: Rodrigues Capitulo, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentin

Riparian Plant Litter Quality Increases With Latitude

Plant litter represents a major basal resource in streams, where its decomposition is partly regulated by litter traits. Litter-trait variation may determine the latitudinal gradient in decomposition in streams, which is mainly microbial in the tropics and detritivore-mediated at high latitudes. However, this hypothesis remains untested, as we lack information on large-scale trait variation for riparian litter. Variation cannot easily be inferred from existing leaf-trait databases, since nutrient resorption can cause traits of litter and green leaves to diverge. Here we present the first global-scale assessment of riparian litter quality by determining latitudinal variation (spanning 107°) in litter traits (nutrient concentrations; physical and chemical defences) of 151 species from 24 regions and their relationships with environmental factors and phylogeny. We hypothesized that litter quality would increase with latitude (despite variation within regions) and traits would be correlated to produce ‘syndromes’ resulting from phylogeny and environmental variation. We found lower litter quality and higher nitrogen:phosphorus ratios in the tropics. Traits were linked but showed no phylogenetic signal, suggesting that syndromes were environmentally determined. Poorer litter quality and greater phosphorus limitation towards the equator may restrict detritivore-mediated decomposition, contributing to the predominance of microbial decomposers in tropical streams

Riparian plant litter quality increases with latitude

Plant litter represents a major basal resource in streams, where its decomposition is partly regulated by litter traits. Litter-trait variation may determine the latitudinal gradient in decomposition in streams, which is mainly microbial in the tropics and detritivore-mediated at high latitudes. However, this hypothesis remains untested, as we lack information on large-scale trait variation for riparian litter. Variation cannot easily be inferred from existing leaf-trait databases, since nutrient resorption can cause traits of litter and green leaves to diverge. Here we present the first global-scale assessment of riparian litter quality by determining latitudinal variation (spanning 107 degrees) in litter traits (nutrient concentrations; physical and chemical defences) of 151 species from 24 regions and their relationships with environmental factors and phylogeny. We hypothesized that litter quality would increase with latitude (despite variation within regions) and traits would be correlated to produce 'syndromes' resulting from phylogeny and environmental variation. We found lower litter quality and higher nitrogen: phosphorus ratios in the tropics. Traits were linked but showed no phylogenetic signal, suggesting that syndromes were environmentally determined. Poorer litter quality and greater phosphorus limitation towards the equator may restrict detritivore-mediated decomposition, contributing to the predominance of microbial decomposers in tropical streams.We thank the many assistants who helped with field work (Ana Chara-Serna, Francisco Correa-Araneda, Juliana Franca, Lina Giraldo, Stephanie Harper, Samuel Kariuki, Sylvain Lamothe, Lily Ng, Marcus Schindler, etc.), Cristina Grela Docal for helping with leaf chemical analyses, and Fernando Hiraldo (former director of EBD-CSIC) for his support. The study was funded by start-up funds from the Donana Biological Station (EBD-CSIC, Spain) and from Ikerbasque to LB, the Fundacao para a Ciencia e Tecnologia (FCT) strategic project ID/MAR/04292/2013 granted to MARE (Portugal), the 'BIOFUNCTION' project (CGL2014-52779-P) from the Spanish Ministry of Economy and Competitiveness (MINECO) and FEDER to LB and J. Pozo, and Basque Government funds (IT302-10) to J. Pozo

Biodiversity conservation: local and global consequences of the application of “rights of nature” by Ecuador

In 2008, Ecuador recognized the Constitutional Rights of Nature in a global first. This recognition implies a major shift in the human-nature relationship, from one between a subject with agency (humans) and an exploitable object (nature), to a more equilibrated relationship. However, the lack of a standard legal framework has left room for subjective interpretations and variable implementation. The recent widespread concessioning of pristine ecosystems to mining industries has set up an unprecedented conflict and test of these rights. Currently, a landmark case involving Los Cedros Protected Forest and mining companies has reached the Constitutional Court of Ecuador. If Ecuador’s highest Court rules in favor of Los Cedros and the Rights of Nature, it would set a legal precedent with enormous impact on biological conservation. Such a policy shift offers a novel conservation strategy, through citizen oversight and action. A ruling against Los Cedros and the Rights of Nature, while a major setback for biodiversity conservation, would be taken in stride by the active social movement supporting these goals, with the case likely moving into international courts. Meanwhile, extractive activities would continue and expand, with known consequences for biodiversity

Latitude dictates plant diversity effects on instream decomposition

Running waters contribute substantially to global carbon fluxes through decomposition of terrestrial plant litter by aquatic microorganisms and detritivores. Diversity of this litter may influence instream decomposition globally in ways that are not yet understood. We investigated latitudinal differences in decomposition of litter mixtures of low and high functional diversity in 40 streams on 6 continents and spanning 113 degrees of latitude. Despite important variability in our dataset, we found latitudinal differences in the effect of litter functional diversity on decomposition, which we explained as evolutionary adaptations of litter-consuming detritivores to resource availability. Specifically, a balanced diet effect appears to operate at lower latitudes versus a resource concentration effect at higher latitudes. The latitudinal pattern indicates that loss of plant functional diversity will have different consequences on carbon fluxes across the globe, with greater repercussions likely at low latitudes

Biodiversity of leaf litter fungi in streams along a latitudinal gradient

Global patterns of biodiversity have emerged for soil microorganisms, plants and animals, and the extraordinary significance of microbial functions in ecosystems is also well established. Virtually unknown, however, are large- scale patterns of microbial diversity in freshwaters, although these aquatic ecosystems are hotspots of biodiversity and biogeochemical processes. Here we report on the first large-scale study of biodiversity of leaf-litter fungi in streams along a latitudinal gradient unravelled by Illumina sequencing. The study is based on fungal commu- nities colonizing standardized plant litter in 19 globally distributed stream locations between 69°N and 44°S. Fungal richness suggests a hump-shaped distribution along the latitudinal gradient. Strikingly, community com- position of fungi was more clearly related to thermal preferences than to biogeography. Our results suggest that identifying differences in key environmental drivers, such as temperature, among taxa and ecosystem types is critical to unravel the global patterns of aquatic fungal diversity