Chironomidae (Diptera) species diversity of estuaries across a land use gradient on the Caribbean coast of Costa Rica / Diversidad de especies de Chironomidae (Diptera) de estuarios en un gradiente de uso de suelo en la costa Caribe de Costa Rica

Abstract The family Chironomidae (Diptera) is the most widely distributed, most diverse, and often the most abundant of all families of benthic macroinvertebrates in aquatic ecosystems, including estuaries and other coastal marine ecosystems. Chironomid assemblages are likely to provide a useful measure of biotic integrity in estuaries of Costa Rica, which lack an intensive estuarine bioassessment tool to support environmental monitoring and regulatory programs. We characterized the taxonomic composition of Chironomidae, tested a Chironomidae Index of Biotic Integrity (CIBI) developed from extrinsic pollution tolerance values for its efficacy in evaluating the surface water quality and physical habitat, and made recommendations for increasing the sensitivity of the CIBI to detect differing degrees of stress across a range of estuaries in Costa Rica. Specifically, we selected nine estuaries within six different watersheds across a land use gradient located on the Caribbean coast of Costa Rica and collected Chironomidae surface-floating pupal exuviae (SFPE) samples biannually for two consecutive years (July 2012, Jan. 2013, July 2013, Jan. 2014). We identified 228 morphospecies and 70 genera from 17 071 Chironomidae pupal exuviae collected from nine estuaries, which ranked in the following order from lowest to highest biotic integrity based on CIBI scores: Estero Negro, Laguna Cuatro, Laguna Jalova, Laguna del Tortuguero, Río Parismina, Laguna Barra del Colorado, Río Pacuare, Río Bananito, and Río Estrella. The CIBI successfully differentiated between estuaries with poor versus good biotic integrity, indicating that CIBI could be used to evaluate the surface water quality and physical habitat of Costa Rican estuaries. We recommend that future studies refine our approach by developing regionally accurate genus and corresponding species-level tolerance values to improve the sensitivity of the CIBI for biological monitoring of Costa Rican estuaries. Rev. Biol. Trop. 66(3): 1118-1134. Epub 2018 September 01.

Resumen La familia Chironomidae (Diptera) es la más ampliamente distribuida, más diversa y a menudo, la más abundante de todas las familias de macroinvertebrados bentónicos en ecosistemas acuáticos, incluyendo estuarios y otros ecosistemas marinos. Probablemente, los ensambles de quironómidos proporcionen una medida útil de integridad biótica en estuarios de Costa Rica, los cuales carecen de una herramienta de evaluación biológica que respalde programas de monitoreo ambiental y programas regulatorios. Caracterizamos la composición taxonómica de Chironomidae, probamos un Índice de Integridad Biótica de Chironomidae (CIBI) desarrollado a partir de valores de tolerancia de contaminación extrínseca, por su eficacia en evaluar la calidad de la superficie del agua y el hábitat físico. Además, realizamos recomendaciones para incrementar la sensibilidad del CIBI para detectar diferentes grados de estrés en un rango de estuarios en Costa Rica. Específicamente, seleccionamos nueve estuarios dentro de seis cuencas diferentes a lo largo de un gradiente de uso de suelo en la costa Caribe de Costa Rica y recolectamos muestras de las exuvias pupales que flotan en la superficie (SFPE) por dos años consecutivos (Julio 2012, Enero 2013, Julio 2013, Enero 2014). Identificamos 228 morfoespecies y 70 géneros de 17 071 exuvias de pupas de Chironomidae recolectadas en nueve estuarios, los cuales se clasificaron en el siguiente orden de menor a mayor integridad biótica basado en los valores del CIBI: Estero Negro, Laguna Cuatro, Laguna Jalova, Laguna del Tortuguero, Río Parismina, Laguna Barra del Colorado, Río Pacuare, Río Bananito, y Río Estrella. El CIBI diferenció eficazmente entre estuarios con integridad biótica pobre versus buena, indicando que el CIBI puede ser usado para evaluar la calidad de la superficie del agua y el hábitat físico de estuarios de Costa Rica. Recomendamos que estudios futuros refinen nuestro planteamiento desarrollando valores de tolerancia de géneros precisos regionalmente y niveles correspondientes de especies para mejorar la sensibilidad del CIBI para el monitoreo de estuarios de Costa Rica.

Land use and biotic integrity in shallow streams of the Hondo River basin, Yucatán Peninsula, Mexico / Uso del suelo e integridad biótica en arroyos someros de la cuenca del río Hondo, península de Yucatán, México

Abstract Aquatic environments face a variety of threats in the Hondo River basin, Southeastern Yucatán Peninsula. Some of these impacts, like pollution by pesticides, may depend on land use and cover. Our objective was to assess the effect of land use/cover using a previously published index of biotic integrity (IBI), based on fishes and designed for shallow streams in the Hondo River basin. Our hypothesis was that land uses that cause deforestation and pollution, such as urbanization, cattle breeding, or sugar cane fields, would be reflected in low IBI values, at least at some spatial scales. The 23 sites originally used in 2008-2009 to estimate by electrofishing the relative abundance and other characteristics of selected fish species and guilds to construct the IBI, were revisited in February 2010, to validate by direct inspection the type of land use/cover suggested by landscape information in digital databases. We analyzed the effect of seven types of land use/cover (agriculture, pasture, human settlements, water bodies, wetlands, forest, and secondary vegetation) on the IBI values, at four spatial scales, i.e., the percent of every land use/cover at progressively larger circles (125, 250, 500, and 1 000 m diameter) centered on the water body where the IBI value was measured. Correlations were established among the percent land/use cover by scale around 23 sites, and with their corresponding IBI values. Then, Student's t tests were calculated to examine significant differences in land use/cover between groups of localities above and below the median IBI value, and Mann-Whitney's U tests were applied to compare IBI values between localities with andwithout a given landscape cover. Agriculture, human settlements, and secondary vegetation correlated negatively with the IBI; forests positively. Differences were significant (p<0.05) for forest (higher in sites with higher IBI values) and human settlements (lower in sites with higher IBI). Of all the landscape categories located in the Hondo River basin, with the exception of pasture, those of anthropogenic origin tended to be detrimental to aquatic biotic integrity.

Resumen Los ambientes acuáticos en la cuenca del río Hondo, sureste de la península de Yucatán, enfrentan diversas amenazas. Algunos de estos impactos, e.g. contaminación por plaguicidas, pueden depender del uso de suelo o cobertura. El objetivo fue evaluar el efecto del uso del suelo/cobertura sobre un índice biótico de integridad (IBI) basado en peces, publicado previamente, diseñado para arroyos someros en esta cuenca. La hipótesis era que los usos del suelo que involucran deforestación y contaminación, entre ellos urbanización, ganadería o cultivo de caña de azúcar, se verían reflejados en valores bajos del IBI, por lo menos a ciertas escalas espaciales. Los 23 sitios usados originalmente para estimar por electropesca la abundancia relativa y otras características de especies y gremios selectos de peces, para construir el IBI, fueron visitados de nuevo en febrero 2010 para validar por inspección directa el tipo de uso del suelo/cobertura sugerido por la información de paisaje en bases de datos digitales. Se analizó el efecto de siete tipos de uso del suelo/cobertura (agricultura, ganadería, asentamientos humanos, cuerpos de agua, humedales, bosque y vegetación secundaria) sobre los valores del IBI, a cuatro escalas espaciales, i.e., el porcentaje de cada uso del suelo/cobertura en círculos progresivamente mayores (125, 250, 500 y 1 000 m de diámetro) centrados en el cuerpo de agua donde se midió el valor del IBI. Los porcentajes de uso del suelo/cobertura por escala se correlacionaron entre sí y con los valores correspondientes del IBI para explorar su asociación; luego, mediante pruebas t de Student se buscaron diferencias significativas en cobertura entre grupos de localidades por encima y por debajo del valor mediano del IBI, así como pruebas U de Mann-Whitney para comparar valores del IBI entre localidades con o sin una cobertura dada. La agricultura, asentamientos humanos y vegetación secundaria mostraron una relación negativa con el IBI, lo cual sugiere un impacto de las actividades humanas sobre la salud de los ecosistemas acuáticos. Las diferencias fueron significativas para el bosque (mayor en sitios con mejor integridad acuática) y los asentamientos humanos (menor en sitios con mayor valor del IBI). De todas las clases paisajísticas en la cuenca del río Hondo, las de origen antrópico, excepto los pastizales para ganadería, tendieron a ser perjudiciales para la integridad biótica acuática.

The protected areas system in Brazil as a baseline condition for wetlands management and fish conservancy: the example of the Pantanal National Park

Considering the need for the Brazilian government to develop tools for environmental monitoring for biodiversity conservancy purposes in the national protected areas system, this paper focuses on determining reference site metrics (or baselines) for adapting the Index of Biotic Integrity (IBI) based on the fish assemblages in the Pantanal National Park (PNP). The habitats in the PNP were grouped into four categories: main rivers, corixos (channels connecting the floodplain), permanent bays, and temporary bays. Fish samplings were performed at 12 points during the dry season (Oct-Nov 2010 and 2011). 146 fish species were identified from the total 18,954 individuals collected with standardized fishing gear. There was no association between the structure of the fish assemblage and categories, suggesting a theory on homogeneity of habitats. The final IBIPNP consists of nine metrics, most of them were framed in excellent class, some in fair, and none in poor. There was no significant difference in IBIPNP scores between the two sampled years. This approach provides a direct application for wetland management purposes.(AU)

É iminente que o Brasil desenvolva ferramentas para monitorar o sistema de áreas protegidas do país, formado especialmente pelas Unidades de Conservação e tendo como foco a proteção efetiva da biodiversidade. Nesse contexto, esse trabalho discute métricas de referência (ou linhas de base) para compor um Índice de Integridade Biótica (IIB) baseado nas comunidades de peixes, tendo como área de estudo o Parque Nacional do Pantanal Matogrossense. Os hábitats encontrados no Parque foram agrupados em quatro estratos ambientais: rios, corixos (cursos d´água que se conectam à planície de inundação) e baías permanentes e temporárias. As coletas de peixes foram realizadas em 12 pontos amostrais durante o período seco (out/nov de 2010 e 2011). Foram identificadas 146 espécies de peixes, totalizando 18.954 exemplares coletados em amostragens padronizadas. Não houve associação entre a estrutura da comunidade e os estratos ambientais, sugerindo homogeneidade de hábitats. O IIB final foi composto por nove métricas, a maior parte alocada na classe excelente de integridade biótica, poucas na classe regular e nenhuma na classe pobre. Não houve diferença significativa no IIB entre os dois anos consecutivos. Esses resultados oferecem subsídios técnicos para a tomada de decisão sobre a gestão das áreas alagáveis no Pantanal brasileiro.(AU)

Integridad biótica de la microcuenca del Río Chiquito, Morelia, Michoacán, México, basada en la comunidad de macroinvertebrados acuáticos

Biotic integrity of the Chiquito River subwatershed, Morelia, Michoacán México, based on the aquatic macroinvertebrate assemblages. The Chiquito River subwatershed supplies 30% of the potable water consumed by the city of Morelia, Michoacan, Mexico. It is necessary to constantly monitor its waters using metrics that evaluate environmental degradation and aquatic assemblages. In the present study, we used the Index of Biotic Integrity for Aquatic Macroinvertebrate Associations (IBIAMA), the Visual-Based Habitat Assessment, and the Most Probable State to calculate the conservation status of the river at six sites along the main channel, including an upper site as a reference. A total of 51 474 specimens were identified, the taxonomic composition was comprised of 69 families distributed into four Phyla, eight classes, eight sub-classes, and 18 orders. The best preserved sites were found in the subwatershed headwater zone. The intermediate zone had impacted hydraulic conditions, environmental quality and biotic integrity. The downstream part of the subwatershed showed the resilient capacity of the river to reestablish macroinvertebrate assemblages and environmental parameters. There is a strong correlation among environmental qualities and the IIBAMA. The use of macroinvertebrates in combination with environmental parameters showed that the Chiquito River subwatershed is stable, rich and integral in aquatic macroinvertebrate assemblages before entering the city of Morelia, and it conserves the processes that regulate the functional dynamics of the subwatershed. Rev. Biol. Trop. 62 (Suppl. 2): 221-231. Epub 2014 April 01.

La microcuenca del Río Chiquito abastece el 30% de agua potable para la ciudad de Morelia, Michoacán, México. Por ello es necesario el monitoreo constante de sus aguas, utilizando mediciones que evalúen el deterioro ambiental y la comunidad de macroinvertebrados acuáticos. Para el presente estudio se utilizó el Índice de Integridad Biótica para las Asociaciones de Macroinvertebrados Acuáticos (IIBAMA). Además de la Valoración de la Calidad Ambiental Visual y el estado más probable del cauce, en seis sitios dentro de la microcuenca y un séptimo fuera de la misma, como referencia. Se identificaron un total de 51 474 organismos: 69 familias distribuidas en cuatro filos, ocho clases, ocho subclases, y 18 órdenes. Los sitios mejor conservados se encuentran en la cabecera de la microcuenca. La zona intermedia se encuentra afectada en la condición hidráulica, calidad ambiental y en su integridad biótica. En la zona baja de la microcuenca, se observó la capacidad “resiliente” del río al restablecerse las comunidades de macroinvertebrados y los parámetros ambientales. Los resultados muestran que la calidad ambiental y el IIBAMA se encuentran correlacionados (r=0.82, p<0.01). El uso de los macroinvertebrados en combinación con los parámetros ambientales demuestran que antes de entrar a la ciudad de Morelia la microcuenca del río Chiquito es un sistema estable, diverso e íntegro en su comunidad de macroinvertebrados acuáticos, y que conserva los procesos que regulan la dinámica funcional de la cuenca.

Propuesta metodllógica preliminar para la estimción del caudal ambiental en prroyectos licenciados por el ministerio de ambiente y desarrollo sostenible (mads), Colombia / Preliminary Methodological Proposal for Estimating Environmental Flows in Projects Approved by the Ministry of Environment and Sustainable Development (MADS), Colombia

Se presenta una propuesta metodológica para estimar los caudales ambientales en grandes proyectos licenciados por la Agencia Nacional de Licencias Ambientales (ANLA) de Colombia, resultado de un convenio interadministrativo suscrito entre el ahora Ministerio de Ambiente y Desarrollo Sostenible (MADS) de Colombia y la Universidad Nacional de Colombia, Bogotá(UNC). El método propuesto parte de garantizar criterios hidrológicos, continúa con una validación hidráulica y de calidad del agua, sigue con la determinación de la integridad del hábitat, en un proceso iterativo que requiere evaluación para las condiciones antes y después de la construcción del proyecto y que permite establecer un caudal que, además de conservar las funciones ecológicas del río, garantiza los usos del recurso aguas abajo. Específicamente dentro del componente biótico, la propuesta incluye la determinación y monitoreo de índices de integridad biótica para cuatro comunidades acuáticas (perifiton, macroinvertebrados, vegetación ribereña y peces), a fin de hacer un seguimiento a los efectos que puede producir la reducción del caudal a mediano y largo plazo. Se presentan los resultados de la aplicación de la metodología en varios proyectos licenciados por el MADS.

A methodological proposal for estimating environmental flows in large projects approved by Agencia Nacional de Licencias Ambientales (ANLA) in Colombian rivers was developed. The project is the result of an agreement between the MADS and the Universidad Nacional de Colombia, Bogotá(UNC). The proposed method begins with an evaluation of hydrological criteria, continues with a hydraulic and water quality validation, and follows with the determination of habitat integrity. This is an iterative process that compares conditions before and after the project construction and allows to obtain the magnitude of a monthly flow that, besides preserving the ecological functions of the river, guarantees the water uses downstream. Regarding to the biotic component, the proposal includes the establishment and monitoring of biotic integrity indices for four aquatic communities (periphyton, macroinvertebrates, riparian vegetation, and fish). The effects that flow reduction may produce in the medium and long term can be assessed by these indices. We present the results of applying the methodology to several projects licensed by the MADS.

Integrity of fluvial fish communities is subject to environmental gradients in mountain streams, Sierra de Aroa, north Caribbean coast, Venezuela

We examined physical habitat and fish assemblages in rivers of the Aroa Mountains (Venezuela) with different levels of environmental protection due to the creation of Yurubí National Park within the drainage. We developed an Index of Biotic Integrity (IBI) and evaluated it using principal components analysis (PCA) and canonical correspondence analysis (CCA). Tributary rivers were divided into classes according to their origin (protected by the park) and physical characteristics of each, including substrate. Fishes were captured using standardized electrofishing. Fish communities showed greater species richness in heterogeneous habitat and protected rivers but overall abundance was higher in unprotected and impacted rivers. The IBI was sensitive to these differences and the scores were higher in protected rivers. The IBI detected degree of disturbance of fish communities without direct consideration of habitat parameters measured. The PCA revealed a gradient in substrate heterogeneity. Similarly, CCA revealed differences in fish assemblage composition along the environmental gradient and that varied with protection status of the river. The relationship between PCA and IBI scores was highly significant (r² = 0.61, P < 0.0001). The PCA and CCA analysis moderately validated the structure and predictability of IBI; but it is still necessary to refine the model and to extend its application for more time and over a wider area.

Foram avaliados o ambiente físico e as assembléias de peixes em rios das montanhas Aroa (Venezuela) com diferentes níveis de proteção ambiental devido a criação do Parque Nacional Yurubí nesta drenagem. Foi desenvolvido um índice de Integridade Biótica (IBI), avaliado através da análise de componentes principais (PCA) e análise de correspondência canônica (CCA). Rios tributários foram divididos em classes, de acordo com sua origem (proteção pelo Parque) e características físicas, incluindo o substrato. Peixes foram capturados utilizando-se pesca-elétrica padronizada. As comunidades de peixes mostraram maior riqueza de espécies em habitats heterogêneos e rios protegidos, porém a abundância foi maior em áreas não protegidas e rios não impactados. O IBI foi sensível a estas diferenças e os escores foram mais elevados em rios protegidos. O IBI detectou o grau de distúrbio nas comunidades de peixes sem a consideração direta dos parâmetros de habitat medidos. O PCA revelou um gradiente de heterogeneidade no substrato. De modo similar, a CCA revelou diferenças na composição da assembléia de peixes ao longo do gradiente ambiental que variou com o estatus de proteção do rio. A relação entre os escores de PCA e IBI foi altamente significativa (r² = 0,61, P < 0,0001). As análises de PCA e CCA validaram moderadamente a estrutura e a previsibilidade do IBI; porém, é necessário refinar o modelo e estender este aplicativo por mais tempo e área mais abrangente.

Uso da taxocenose de peixes como indicadora de degradação ambiental no rio Paraíba do Sul, Rio de Janeiro, Brasil

An adaptation of index of biotic integrity (IBI) was performed for the first time in Brazil at the Rio Paraíba do Sul, between Barra Mansa and Barra do Piraí, a very important extent of this river because of the high pollution levels, and for being the main abstraction source of Rio de Janeiro city water supply. A monthly standardised sampling programme, from March-1995 to February-1996, was carried out at four sites. Seines, casting nets and net trays were used for catching fishes. IBI was obtained by integrating 12 ecological and environmental attributes of fish taxocene, populations, and individual organisms to assess biological integrity based in Species Composition, Trophic Structure and Fish Condition. Overall, water quality was classified between poor and fair and an improvement was detected between the high polluted Barra Mansa site and the less polluted Barra do Piraí site, showing the capacity of restoration of the river over this 50 km. Seasonally, the best conditions were reached from March to August, and the worse, from September to February, when most aloctone materials are brought to the river.