Altitudinal distribution of the functional feeding groups of aquatic macroinvertebrates using an ecological network in Andean streams / Distribución altitudinal de los grupos funcionales de alimentación de macroinvertebrados acuáticos utilizando una red ecológica en arroyos andinos

Abstract Introduction: Analysis of functional feeding groups (FFG) in aquatic macroinvertebrates is important in understanding the structure, function, and dynamics of ecological processes in ecosystems. Modularity refers to the degree of compartmentalization of food webs and varies between -1 and 1. A network with a modularity value close to 1 is resilient to disturbances and can be interpreted as an indicating factor for the stability of communities. Objective: In this study, we analyzed the trophic structure of benthic macroinvertebrates in La Nitrera stream, the San Juan River, and the Cauca River in the Colombian Andes. Methods: The study was supported by ecological networking techniques using Gephi software. We studied nine sites in dry, rainy, and transition seasons in 2017 and 2018, monitoring changes in the altitude gradient. At each of the sites, the organisms were captured and determined, and physicochemical and hydraulic information was obtained. Results: The variance component analysis allowed to explain the variability of the data by relating the following environmental variables: FFG, diversity, richness, modularity, season, and time. Simple multifactorial ANOVA indicated that significant changes in FFG were associated with altitude, and modularity to time. The allocation of the FFG was done by stomach analysis and secondary information. Conclusion: The transition season had the highest modularity, possibly due to the recolonization of some biotopes caused by the decrease in the velocity of water currents. La Nitrera and San Juan presented higher values than the Cauca, which may indicate that the altitudinal change and velocity of water currents affects the compartmentalization of the network.

Resumen Introducción: El análisis de grupos funcionales de alimentación (GFA) en macroinvertebrados acuáticos es importante para comprender la estructura, función y dinámica de los ecosistemas de procesos ecológicos. La modularidad se refiere al grado de compartimentación de las redes alimentarias y varía entre -1 y 1. Una red con un valor de modularidad cercano a 1 es resistente a las alteraciones y puede interpretarse como un factor indicativo para la estabilidad de las comunidades. Objetivo: En este estudio se analizó la estructura trófica de los macroinvertebrados bentónicos, un elemento importante en la calidad ambiental, en el arroyo La Nitrera, el río San Juan y el río Cauca. Métodos: El estudio contó con el apoyo de técnicas de redes ecológicas utilizando el software Gephi. En 2017 y 2018, estudiamos nueve sitios en estaciones secas, lluviosas y de transición, monitoreando cambios en el gradiente de altitud. En cada uno de los sitios se capturaron y determinaron los organismos y se recogió información fisicoquímica e hidráulica. Resultados: El análisis de componentes de varianza permitió explicar la variabilidad de los datos relacionando las siguientes variables ambientales: GFA, diversidad, riqueza, modularidad, estación y tiempo. La ANOVA simple multifactorial indicó que existen cambios significativos en los GFA en relación con la altitud, y la modularidad con el tiempo. La asignación de los GFA se realizó mediante análisis estomacal e información secundaria. Conclusión: La temporada de transición tuvo la mayor modularidad, posiblemente debido a la recolonización de algunos biotopos provocada por la disminución de la velocidad del cauce. La Nitrera y San Juan presentaron valores superiores a los del Cauca, lo que puede indicar que el cambio altitudinal y la velocidad de las corrientes de agua influyen en la compartimentación de la red.

Impact of treated sewage on meiobenthic nematodes: a case study from the Tunisian Refining Industries Company / Impacto de esgoto tratado em nematoides meiobentônicos: um estudo de caso da Tunisian Refining Industries Company

The main objective of the current study was to assess the impact of the water taken from the 'Tunisian Refining Industries Company' on meiobenthic nematodes, before and after a series of treatments in decantation basins followed by its discharge in Bizerte bay, Tunisia. The comparison of environmental parameters of the two types of water was clearly indicative of an improvement in the quality of treated waters after a significant reduction in their loads in hydrocarbons. Overall, the water retained a good quality after being treated by 'Tunisian Refining Industries Company' before discharge in the sea. At the end of the experiment, differential responses were observed according to the richness of sediment in organic matter and hydrocarbons. Thus, it was apparent that the nematode assemblage exposed to the treated waters was closer to controls and associated to higher values of abundance, than that under untreated ones. It was also assumed that the species Microlaimus honestus De Man, 1922, Paramonohystera proteus Wieser, 1956 and Cyartonema germanicum Juario, 1972 are sensitive bioindicators of bad environmental statues and of hydrocarbon presence in the environment. On the other hand, Metoncholaimus pristiurus (Zur Strassen, 1894) Filipjev, 1918 would rather be classified as a positive bioindicative species of this type of pollutants.

O principal objetivo do presente estudo foi avaliar o impacto da água retirada da "Tunisian Refining Industries Company" sobre os nematoides meiobentônicos, antes e depois de uma série de tratamentos em bacias de decantação seguidos de seu descarte na baía de Bizerte, Tunísia. A comparação dos parâmetros ambientais dos dois tipos de água foi claramente indicativa de uma melhoria na qualidade das águas tratadas após uma redução significativa das suas cargas em hidrocarbonetos. No geral, a água reteve uma boa qualidade após ser tratada pela "Tunisian Refining Industries Company" antes da descarga no mar. Ao final do experimento, foram observadas respostas diferenciais de acordo com a riqueza de sedimentos em matéria orgânica e hidrocarbonetos. Assim, ficou claro que a assembleia de nematoides exposta às águas tratadas estava mais próxima dos controles e associada a maiores valores de abundância do que nas não tratadas. Também foi assumido que as espécies Microlaimus honestus De Man, 1922, Paramonohystera proteus Wieser, 1956 e Cyartonema germanicum Juario, 1972 são bioindicadores sensíveis de más estátuas ambientais e da presença de hidrocarbonetos no meio ambiente. Por outro lado, Metoncholaimus pristiurus (Zur Strassen, 1894) Filipjev, 1918 preferiria ser classificado como uma espécie bioindicativa positiva deste tipo de poluentes.

Macrozoobenthos in an altitudinal gradient in North Patagonian Cautín River (Araucanía Region, Chile) / Macrozoobentos em gradiente altitudinal no norte da Patagônia, Rio Cautín (38° S, região da Araucanía, Chile)

The Cautín River is closely related with the economic development of Temuco city, (38°S; Chile). Existing knowledge of the Cautín River is limited to information about its biological characteristics as a reference for the evaluation and assessment of water quality. The object of this study was to develop taxonomic characterisation of the benthic macroinvertebrates along the main course of the Cautín River, and to study the community structure using correlation analysis between community parameters. To carry out this research, the macroinvertebrate community was studied in 10 sampling sites distributed along the main course of the river. The samples were taken in summer (1997 and 2000), when optimal hydrological conditions existed. Analysis of the samples showed that the benthic fauna was composed of 56 taxa, the dominant group being insects with 48 taxa. Three main sectors were recognised in the course of the Cautín River: high, middle and low. Each sector has restricted-distribution species, while other species are widely distributed along the river. These distribution patterns seem to be influenced by dissolved oxygen concentration, temperature, altitudinal distribution and anthropo-cultural activity, present at every sampling site. Finally, this research provides a first approach to the biology of the Cautín River. Further studies could be planned on the basis of this knowledge to investigate water quality indicators based on macroinvertebrate communities.

O rio Cautín está intimamente relacionado ao desenvolvimento econômico da cidade de Temuco (38°S; Chile). Quanto ao conhecimento total do rio Cautín, existem informações limitadas sobre as características biológicas que podem servir de referência para a avaliação da qualidade da água. Este estudo tem o objetivo de caracterizar os macroinvertebrados bentônicos taxonomicamente ao longo do curso principal do rio Cautín e estudar a estrutura da comunidade usando análise de correlação entre os parâmetros dela. Para realizar esta pesquisa, a comunidade de macroinvertebrados foi estudada em dez locais de estudo distribuídos ao longo do rio principal. As amostras foram coletadas no verão (1997 e 2000), em razão das condições hidrológicas ideais. A análise das amostras mostrou que a fauna bentônica é composta de 56 táxons, sendo o grupo dominante o de insetos com 48 táxons. Na distribuição do principal no curso do rio, três setores são reconhecidos: alto, médio e baixo no rio Cautín. Cada setor possui espécies de distribuição restrita e outro com ampla distribuição ao longo do rio. Esses padrões de distribuição parecem influenciar a concentração de oxigênio dissolvido, a temperatura, a distribuição altitudinal e a atividade antropocultural desenvolvida em todos os locais de amostragem. Finalmente, esta pesquisa fornece uma primeira abordagem biológica do rio Cautín e, de acordo com esses conhecimentos, um estudo posterior pode ser planejado em relação aos indicadores de qualidade da água e com base nas comunidades de macroinvertebrados.

Diversidad malacológica del humedal marino-costero Las Lisas-La Barrona en el Pacífico de Guatemala / Malacological diversity of the Las Lisas-La Barrona marine coastal wetland in the Pacific of Guatemala

Los moluscos son uno de los grupos faunísticos dominantes en ambientes estuarinos con bosque de manglar como el humedal Las Lisas-La Barrona. Forman parte de la transferencia de energía a través de las redes tróficas y contribuyen a la estructuración de los hábitats bénticos. El humedal Las Lisas-La Barrona se ubica en el litoral Pacífico de Guatemala. Se determinó la diversidad de la comunidad de moluscos, así como su relación con los parámetros fisicoquímicos del agua. Se realizaron ocho muestreos (enero a agosto) en 2017, utilizando parcelas con un área de 16 m2 en seis sitios de bosque de manglar y cuatro sitios en el canal estuarino, distribuidos en el humedal. La riqueza de moluscos del humedal está comprendida por 26 especies correspondientes a 18 familias y 22 géneros. Las especies más abundantes de gasterópodos fueron Cerithideopsis californica (Adams, 1852) y Littoraria fasciata (Gray, 1839) y de bivalvos Iliochione subrugosa (Wood, 1828) y Larkinia grandis (Broderip & Sowerby, 1829). Los sitios correspondientes a bosque de manglar presentaron una mayor cantidad de moluscos, principalmente gasterópodos. La distribución de las especies dominantes, no está dada por los factores fisicoquímicos del agua, pudiendo ser otros factores como la disponibilidad de hábitat y alimento los que rijan su distribución dentro del humedal. Algunos factores como la influencia de agua marina dentro del humedal, las altas concentraciones de oxígeno disuelto y pH ligeramente básicos, así como la calidad del agua en general, hacen del humedal Las Lisas-La Barrona un área muy diversa en cuanto a especies de moluscos.

Molluscs are one of the dominant faunistic groups in estuarine environments with mangrove forests such as the Las Lisas-La Barrona wetland. They are part of the transfer of energy through trophic networks and contribute to the structuring of the benthic habitats. The Las Lisas-La Barrona wetland is located on the Pacific coast of Guatemala. The diversity of the mollusk community, as well as its relationship with the physicochemical parameters of the water was determined. Eight samplings were carried out (January to August) in 2017, using parcels with an area of 16 m2 in six mangrove forest sites and four sites in the estuarine channel, distributed along the wetland. The mollusk richness of the wetland is comprised of 26 species corresponding to 18 families and 22 genera. The most abundant species of gastropods were Cerithideopsis californica (Adams, 1852) and Littoraria fasciata (Gray, 1839) and bivalves Iliochione subrugosa (Wood, 1828) and Larkinia grandis (Broderip & Sowerby, 1829). The sites corresponding to mangrove forest, presented a greater amount of mollusks, mainly gastropods. The distribution of dominant species is not given by the physicochemical factors of the water, being able to be other factors such as the availability of habitat and food that govern their distribution within the wetland. Some factors such as the influence of seawater in the wetland, the high concentrations of dissolved oxygen and the slightly basic levels of pH, as well as water quality in general, make the Las Lisas-La Barrona wetland a very diverse area in terms of mollusk species

Crustáceos (Decapoda y Stomatopoda) del R.V. Skimmer y R.V. Victor Hensen en el Golfo de Nicoya, Pacífico, Costa Rica / Crustaceans (Decapoda and Stomatopoda) from the R.V. Skimmer and R.V. Victor Hensen in the Gulf of Nicoya, Pacific, Costa Rica

Resumen El acceso a datos actualizados, sobre los nombres y distribución de las especies de crustáceos presentes en un área en particular, es un primer paso para evaluar cambios debidos a factores locales, regionales o globales, como la sobrepesca, la contaminación y el cambio climático. Los datos en este estudio están basados en las expediciones de los buques de investigación Skimmer (20 estaciones, 1979-1980) y Victor Hensen (1993-1994, 12 estaciones) en el estuario del Golfo de Nicoya. Los crustáceos fueron recolectados mediante redes de arrastre tipo Otter (Skimmer, malla 3.5 cm) y por tipos Otter y Beam (V. Hensen, mallas de 2.5 cm y 1.9 cm) a profundidades entre 10 y 228 m. Datos en dos estudios posteriores aportaron información para una zona de entre-mareas en la región superior del Golfo y para estaciones en la boca del estuario, lo que incrementa el ámbito de profundidad de 0 a 350 m. Se revisaron las publicaciones originales y se hicieron 32 actualizaciones de los nombres de las especies con base en la literatura reciente y en la página de red World Register of Marine Species (WORMS). El total de especies para ambas expediciones fue de 131, del que 119 fueron decápodos y 12 fueron estomatópodos. Los datos en los otros dos estudios, así como la revisión de las colecciones en el Museo de Zoología de la Universidad de Costa Rica, incrementó en 43 el número de registros, para un total de 174 especies en los sedimentos del estuario. Para el Skimmer el número mínimo de especies en una estación fue de cuatro (tres estaciones) y el máximo de 27, con un promedio de 12.3 especies / estación. Para el V. Hensen el mínimo de especies en una estación fue de ocho, con un máximo de 27 y un promedio de 17 especies / estación. Las especies presentes en 50 % o más de las 20 estaciones de la expedición del Skimmer, fueron: Callinectes arcuatus, Rimapenaeus faoe, Penaeus brevirostris, Achelous asper y Hepatus kossmanni. Para la expedición del V. Hensen las especies presentes en más del 50 % de las 12 estaciones, fueron: A. asper, Sicyonia disdorsalis, S. picta y Persephona subovata. Durante el estudio del Skimmer, un total de 15 especies fueron encontradas en solo una estación, mientras que para el V. Hensen el número fue de 26. Se digitalizaron dos matrices de datos de presencia-ausencia de las especies en las estaciones y con base en los nombres actualizados de las especies recolectadas por el Skimmer (57 especies x 20 estaciones) y V. Hensen (82 especies x 12 estaciones) se les aplicó un Análisis No Métrico Dimensional de Escala (NMDS) para obtener una distribución de las estaciones en un espacio bi-dimensional. Los resultados revelaron unos grupos heterogéneos de estaciones. Algunos sub-grupos de tres o cuatro estaciones concuerdan con su proximidad geográfica. Las cuatro estaciones del V. Hensen en la boca del estuario a profundidades mayores a los 60 m fueron separadas más claramente de las otras, y podrían indicar una transición, desde aguas estuarinas hacia aguas profundas, en la composición de la fauna de crustáceos. Evaluaciones futuras de la diversidad de crustáceos del Golfo de Nicoya deben de considerar la amplia distribución espacial de algunas especies y la restringida de otras. La variabilidad temporal es también importante en el estuario, tal como lo evidenció la oscilación de la población de Pinnixulala valerii en un periodo de tres años.(AU)

Abstract The access to updated data on the names of the crustacean species and their distribution in a given area is a first step to evaluate changes due to local, regional and global factors such as overfishing, pollution, and climatic change. Data in this study are based on the expeditions of the RV Skimmer (20 stations, 1979-1980) and RV Victor Hensen (1993-1994, 12 stations) in the Gulf of Nicoya estuary. The crustaceans were collected by means of an Otter trawl (Skimmer, mesh 3.5 cm) and by Otter and Beam trawls (V. Hensen, mesh 2.5 cm and 1.0 cm, respectively) at depths from 10 m to 228 m. Data from two later studies were also included, one from an intertidal flat in the upper Gulf and the other from stations at the mouth of the estuary, which expand the depth range from 0 to 350 m. The list of species in the original publications were updated and 32 corrections were made based on recent literature and the web page, World Register of Marine Species (WORMS). The total number of species for both surveys was 131, of which 119 were decapods and 12 were stomatopods. Data from the other two studies and from the crustacean collection deposited at the University of Costa Rica Zoology Museum added 43 records for a total of 174 species collected in sediments from the estuary. For the Skimmer, the minimum number of species found in one station was four (three stations) and the maximum was 27, with an average of 12.3 species / station. For the V. Hensen, the minimum of species found in one station was eight, with a maximm of 27 and an average of 17 species / station. The species present in 50 % or more of the 20 stations of the Skimmer expedition, were: Callinectes arcuatus, Rimapenaeus faoe, Penaeus brevirostris, Achelous asper and Hepatus kossmanni. For the V. Hensen expedition, the species present in 50 % or more of the 12 stations, were: A. asper, Sicyonia disdorsalis, S. picta, and Persephona subovata. During the Skimmer survey a total of 15 species were found at only one station, while for the V. Hensen the number was 26. Two presence-absence matrices based on the updated names of the crustaceans collected by the Skimmer (57 species x 20 stations) and V. Hensen (82 species x 12 stations) were analyzed by Non Metric Dimensional Scaling (NMDS) to display the distribution of stations in a two-dimensional space. The results revealed heterogeneous groups of stations. Several sub-groups of two or three stations agreed with their geographical proximity. The four V. Hensen stations, located at the mouth of the estuary at depths greater than 60 m, were separated more clearly from the others and may indicate a transition, from estuarine to deep waters, in the composition of the crustacean fauna. Future evaluations of the crustacean diversity of the Gulf of Nicoya must take into account the wide spatial distribution of some species and the patchy distribution of others. Temporal variability is also important in the estuary as evidenced by the population oscilallations of Pinnixulala valerii over a three year period.(AU)

Colonization of benthic invertebrates on artificial and natural substrate in a Neotropical lotic environment in Southern Brazil

The objective of this research was to validate the colonization process on natural and artificial substrates by benthic invertebrates in a tropical stream in South Brazil. The samples were performed in July and August-2012, and 32 samplers were used, being 16 natural and 16 artificial substrates. In each sample, two replicas were taken for each substrate at the 2th, 4th, 7th, 14th, 21th28th, 35th and 42thdays of colonization. The organisms were identified to the lowest possible taxonomic level. In both substrates 3,070 benthic invertebrates were detected, of which 1,753 individuals were collected on the natural substrate, and 1,317 on the artificial substrate. From the identified taxa 8.5% were not dominant (Anacroneuria, Orthocladiinae, Tupiara, Smicridea, Baetodes, Tupiperla, Macrogynoplax, Gripopteryx, Cylloepus, Macrelmis, Microcylloepus, Hetaerina, Argia, Coryphaeschna, Atopsyche, Pomacea, Corydalus, Leptohyphes and Eccoptura), and31.5% were dominant (Tanypodinae, Chironominae, and Paragripopteryx). The genus Simulium was very common, dominant and abundant, representing 65% of the collected individuals. No significant difference was found in the abundance and species composition between artificial and natural substrates. On the natural substrate, the higher colonization index was at the 35th day with 459 individuals, and the lowest was at the 14th day, with 87. On the artificial substrate the highest index was at the 42thday with 337 individuals, and the lowest was at the 4th day, with 85. Both natural and artificial substrates are efficient in characterizing the benthic community. In the evaluation of the ecological succession, it was not possible to observe a pattern that described the process, since the composition was nearly constant throughout the study period.

Impact assessment of an effluent discharge on benthic macroinvertebrates in a subtropical river using indexes

Benthic macroinvertebrates are used as environmental bioindicators in the assessment of water quality in rivers and lakes, due to the sensitivity of some taxa to pollution. The objective of this research was to evaluate the consequences of industrial effluent discharge on the structure of the benthic community present in a river in the subtropical region of Brazil. The organisms were collected at three points of the Coutinho River, in 2013 (September and November) and 2014 (January and March). To characterize the community were calculated density, Shannon diversity index (H ́), Pielou equitability (J), taxa richness, Biotic Indices (Biological Monitoring Working Party - BMWP, Average Score Per Taxon - BMWP-ASPT, Family Biotic Index – FBI) and Canonical Correspondence Analysis (CCA) between sampling points and biotic and abiotic variables. Fifteen taxa were identified and among the collected organisms, the family Chironomidae was the most representative, followed by Oligochaeta, Hirudinea, Bivalvia, Gastropoda. According to the results of the biological indices, point 1 indicated moderate pollution and the following points (2 and 3) showed severe pollution. These indices showed poor waters with a high degree of pollution. The results were efficient in detecting the environmental impacts suffered by the river and suggest the necessity of a continuous monitoring of the same.

Efecto del microhábitat sobre la abundancia y riqueza específica de los macroinvertebrados bentónicos en dos ríos tropicales de montaña, Guatemala / Effect of microhabitat on the abundance and specific richness of benthic macroinvertebrates in two tropical mountain streams, Guatemala

Los macroinvertebrados bentónicos cumplen funciones ecológicas importantes en los sistemas lóticos, como el traspaso de energía a través de las redes tróficas, la descomposición de la materia orgánica, el reciclaje de nutrientes y la mezcla de sedimentos. Uno de los principales factores que definen la composición del ensamble de macroinvertebrados es la disponibilidad de microhábitats. Debido a ello, se evaluó el efecto de ocho microhábitats (hojarasca, grava, piedras, roca, musgo, vegetación acuática, pozas y cataratas), así como de la velocidad y profundidad, sobre la abundancia y riqueza específica de los macroinvertebrados en los ríos La Labor y Tzununá en la cuenca del lago Atitlán en el altiplano de Guatemala. Se colectaron 19,529 organismos correspondientes a 91 taxa, 49 familias y 65 géneros. El microhábitat que presentó mayor abundancia fue hojarasca (7,723 organismos) y pozas presentó la menor (652 organismos). En cuanto a riqueza, piedras presentó la mayor riqueza (41 taxa) y musgo tuvo la menor (28 taxa). Se evidenció que el microhábitat tuvo un efecto significativo sobre la abundancia y la riqueza (p < .05), ésta última también se vio influenciada por la profundidad (p = .030). Se concluyó que el microhábitat es un factor importante, para determinar la composición de la comunidad de macroinvertebrados; ya que la presencia y dominancia de elementos de heterogeneidad en los ríos, contribuye a incrementar la diversidad del hábitat físico, así como las opciones de alimento y refugio, promoviendo la abundancia y riqueza de macroinvertebrados en los sistemas lóticos.

Benthic macroinvertebrates serve important ecological functions in lotic systems, such as the transfer of energy through trophic networks, decomposition of organic matter, nutrient recycling and sediment mixing. One of the main factors that define the composition of the macroinvertebrate assemblage is the availability of microhabitats. The survey evaluated the effect of eight microhabitats (leaf litter, gravel, stones or pebbles, rock, moss, aquatic vegetation, pools and waterfalls), as well as speed and depth, on the abundance and specific richness due to rarefaction of the macroinvertebrates in La Labor and Tzununá rivers, which are part of the Lake Atitlán basin in the Guatemalan highlands. In this area 19,529 organisms corresponding to 91 taxa, 49 families and 65 genera were collected. The highest abundance was in leaf litter microhabitat (7,723 organisms), while stones showed the highest richness (41 taxa). Pools had the lowest abundance (652 organisms) and moss had the lowest richness (28 taxa). The microhabitat has a significant effect on abundance and richness (p < .05), also depth has a significant effect on richness (p = .030). The microhabitat is an important factor, to determine the composition of the macroinvertebrate community, because the presence and dominance of elements of heterogeneity in the rivers contributes to increase the diversity of the physical habitat, which provides refuge and food that satisfy the requirements of organisms promoting the abundance and richness of macroinvertebrates in lotic systems.

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.

The effect of seasonal and human pressure on macrobenthic fauna in the Caroni Swamp Ramsar Site, Trinidad and Tobago / Efecto de la presión estacional y humana en la fauna macrobentónica del sitio Ramsar pantano Caroní, Trinidad y Tobago

Abstract Human pressures have placed many tropical estuaries in developing countries under increased levels of stress. The Caroni Swamp Ramsar Site, the largest mangrove swamp along the west coast of Trinidad, has been subjected to high levels of anthropogenic impacts including hydrological alteration and pollution from land-based sources since the 1920's. While most of these impacts have been well documented, limited information exists on the macrobenthic communities in the swamp. This study addresses the paucity of information. The macrobenthic fauna in the main waterways of Caroni Swamp was sampled at 12 locations using a Van Veen 0.025 m2 grab, once in the dry (April) and wet (August) season of 2015 with a total of 144 samples. The samples were sorted, counted and species were identified to the lowest possible taxonomic level. A total of 55 taxa were identified with polychaetes being the most abundant taxa. The ecological status of the macrobenthos was assessed using AZTI's Marine Biotic Index (AMBI) and the multivariate-AMBI (M-AMBI). Physicochemical parameters were measured with a YSI multiparameter metre. Chemical analyses were also conducted on nitrates, nitrites, ammonia and reactive phosphates using standard methods. Overall, AMBI characterised the Caroni Swamp as "slightly disturbed" with a macrobenthic community of "poor" ecological status according to M-AMBI. Generally, the quality of the environment improves from the dry season to the wet season. However, seasonal variations in AMBI and M-AMBI were found to be site specific as some showed improvement in ecological status and macrozoobenthos quality while others showed degradation from the dry season to the wet season. The stations to the North of the swamp showed improvement from the dry season to the wet season while the opposite was observed in the more Southern stations. One notable characteristic of the swamp was the high levels of pollutants, particularly ammonia, recorded in one of its major waterways, the Caroni River. This is in contrast to the other waterways within the swamp which experience much lower levels of pollutant input from land-based sources. The assessment of the Caroni Swamp using AMBI and M-AMBI may be useful for informing management strategies to conserve the wetland and improve environmental quality. Rev. Biol. Trop. 66(3): 1101-1117. Epub 2018 September 01.

Resumen Los estuarios tropicales de países en desarrollo han experimentado un aumento en los niveles de estrés debido a la presión humana. El sitio Ramsar pantano Caroní, el manglar más grande de la costa oeste de Trinidad, ha estado sujeto a altos niveles de impacto antropogénico, incluyendo alteraciones hidrológicas y contaminación de fuentes terrestres desde la década de 1920. Aunque la mayoría de estos impactos han sido bien documentados, existe información limitada sobre las comunidades macrobentónicas en el pantano. Este estudio aborda esta escasez de información. Se muestreó la fauna macrobentónica en el canal principal del pantano Caroní en 12 localidades utilizando una draga Van Veen de 0.025 m2, una vez durante la época seca (Abril) y la época lluviosa (Agosto) 2015, con un total de 144 muestras. Las muestras fueron ordenadas, contadas y las especies se identificaron al menor nivel taxonómico posible. Se identificaron un total de 55 taxa, siendo los poliquetos el taxa más abundante. El estatus ecológico del macrobentos se evaluó utilizando el Índice Marino Biótico de AZTI (AMBI) y el AMBI-multivariado (M-AMBI). Los parámetros fisicoquímicos se midieron con un multiparámetro YSI. Los análisis químicos también se realizaron para nitratos, nitritos, amonio y fostatos activos utilizando métodos estándar. En conjunto, el índice AMBI caracterizó el pantano Caroní como "levemente alterado" con una comunidad macrobentónica de categoría "pobre" de acuerdo al M-AMBI. Generalmente, la calidad de los ambientes incrementa desde la época seca hasta la época lluviosa. Sin embargo, las variaciones estacionales en los índices AMBI y M-AMBI fueron específicas a la localidad, mostrando algunas un incremento en el estatus ecológico y calidad del macrozoobentos, mientras que otros mostraron una degradación de la época seca a la época lluviosa. Las estaciones al norte del pantano mostraron una mejora de la época seca a la época lluviosa, mientras que se presentó lo contrario en las estaciones más al sur. Una característica notable del pantano fueron los altos niveles de contaminantes, particularmente amonio, registrado en uno de los canales principales del río Caroní. Esto contrasta con los otros canales del pantano que experimentan niveles menores de aporte de contaminantes de fuentes terrestres. La evaluación del pantano Caroní utilizando los índíces AMBI y M-AMBI puede ser una base útil de información para las estrategias de manejo y conservación del humedal y mejorar su calidad ambiental.

Interstitial annelids from the Caribbean Coast of Colombia / Anélidos intersticiales de la costa Caribe de Colombia

Abstract A total of 298 species of polychaetes have been recorded from Colombia. However, only the family Protodrilidae has been reported from the marine interstitial realm. We here aim at identifying the interstitial annelids inhabiting the sandy beaches in Santa Marta region to the most accurate taxonomic level based on light microscopy examinations. Our samples, collected from the intertidal zone at three touristic beaches in the department of Magdalena (Santa Marta Bay, Rodadero Bay, and Taganga Bay), yielded a total of 83 specimens, which we assigned to five families, ten genera and nine species. From those, two families, eight genera, and the species Hesionides gohari, Neogyptis mediterranea, Neopetitia amphophthalma, Westheidesyllis gesae, and Syllis beneliahuae represent new records for the Colombian fauna. This survey should be considered as a first step towards a complete knowledge of the Colombian diversity of interstitial annelids, and our results significantly contribute to fill the gap of our current knowledge, suggesting a high diversity of species comparable to this in better-known areas of the Caribbean and the Atlantic coasts of Brazil. A brief diagnosis, comments on distribution and ecology, and remarks are provided for each record, in order to facilitate the re-identification of the species. Rev. Biol. Trop. 66(2): 658-673. Epub 2018 June 01.

Resumen Un total de 298 especies de poliquetos han sido registradas para Colombia. Sin embargo, solo la familia Protodrilidae ha sido reportada para el medio marino intersticial. El objetivo de este estudio fue identificar los anélidos intersticiales que habitan en playas arenosas de la región de Santa Marta hasta la categoría taxonómica más precisa, basados en observaciones al microscopio de luz. Las muestras fueron recolectadas en la zona intermareal de tres playas turísticas en el departamento del Magdalena (La bahía de Santa Marta, bahía de Rodadero y bahía de Taganga), resultando un total de 83 especímenes, los cuales fueron asignados a cinco familias, diez géneros y nueve especies. De estos, dos familias, ocho géneros y las especies Hesionides gohari, Neogyptis mediterranea, Neopetitia amphothalma, Westheidesyllis gesae y Syllis beneliahuae representan nuevos registros para la fauna de Colombia. Este trabajo debería ser considerado como el primer paso hacia el conocimiento de la diversidad de anélidos intersticiales en Colombia y los resultados contribuyen significativamente a llenar el vacío de información en el tema, sugiriendo una alta diversidad de especies comparable con la de áreas mejor conocidas del Caribe y de la costa atlántica de Brasil. En este trabajo se provee una breve diagnosis, comentarios sobre la distribución y ecología, y anotaciones para cada registro, con el propósito de facilitar la re-identificación de las especies.

Assessment of ecological water quality along a rural to urban land use gradient using benthic macroinvertebrate-based indexes / Avaliação da qualidade ecológica da água ao longo de um gradiente rural-urbano utilizando índices baseados em macroinvertebrados bentônicos

Agricultural practices such as livestock grazing and tilling can result in soil erosion and runoff of fine sediments, nutrients (e.g. nitrogen, phosphorus, potassium) and pesticides, leading to degradation of aquaticenvironments. Urbanization is also responsible for a variety of impacts on fluvial ecosystems, including pollution by heavy metals, oil, domestic sewage and garbage. In this study, we evaluate the impact of land use on stream health of the Uberabinha river catchment. Overall, rural streams presented better ecological conditions than urban streams. Both species composition and abundance of benthic communities showed significant differences between rural and urban streams. Urban streams presented a higher dominance of Oligochaeta, Hirudinea and Gastropoda, bioindicators of poor water quality. Rural streams presented significantly greater richness and diversity. Compared to urban streams, rural streams presented a significantly higher number of Ephemeroptera, Plecoptera, Trichoptera, Odonata and Hemiptera taxa. Our analyses also showed congruence (high correlation) among the classical biodiversity metrics (Shannon-Wiener index ­ H', Pielou's measure of eveness ­ J) and monitoring parameters (% Ephemeroptera, Plecoptera and Trichoptera ­ EPT, Biological Monitoring Work Party ­ BMWP, bioindicator approach and Rapid Assessment Protocol ­ RAP, a habitatbased approach). Five from seven rural streams presented good water quality according to both BMWP and RAP and none of the urban streams presented good water quality. Our results show that the urban streams of Uberlândia municipality are poor ecosystems, and require improved management actions by environmental authorities. We also encourage that the riparian forest restoration and management carried out in the upper portion of Uberabinha River catchment to be extended to the urban area of the municipality.

Atividades agrícolas, como pecuária e cultivo de lavouras, podem levar a degradação dos ambientes aquáticos vizinhos, provocando erosão do solo e o carreamento de sedimentos finos, nutrientes (por exemplo, nitrogênio, fósforo, potássio) e pesticidas para os leitos dos rios. A urbanização também é responsável por uma variedade de impactos nos sistemas fluviais, incluindo a poluição por metais pesados, óleos, esgoto doméstico e lixo. Neste estudo, nós avaliamos o impacto do uso da terra na saúde da bacia hidrográfica do rio Uberabinha, utilizando macroinvertebrados bentônicos como bioindicadores da qualidade da água. Em geral, os córregos rurais apresentaram melhores condições ecológicas do que os córregos urbanos. Tanto a composição de espécies como a abundância da comunidade bentônica mostraram diferenças significativas entre os dois grupos. Os córregos urbanos apresentaram uma maior dominância de Oligochaeta, Hirudinea e Gastropoda, organismos indicadores de baixa qualidade ambiental. Os córregos rurais apresentaram maior riqueza e diversidade de grupos taxonômicos, tais como Ephemeroptera, Plecoptera, Trichoptera, Odonata e Hemiptera. Nossas análises mostraram congruência (alta correlação) entre os índices tradicionais de diversidade (índice de Shannon- Wiener - H ', equitabilidade de Pielou - J) e as métricas de biomonitoramento (% Ephemeroptera, Plecoptera e Trichoptera ­ EPT, Biological Monitoring Work Party ­ BMWP , índice baseado na composição taxonômica das comunidades e Rapid Assessment Protocol ­ RAP, abordagem baseada em características físicas do habitat). Cinco dos sete córregos rurais analisados apresentaram boa qualidade da água, de acordo com BMWP e RAP. Nenhum dos córregos urbanos apresentaram boa qualidade ambiental. Nossos resultados mostraram que córregos urbanos do município de Uberlândia possuem má qualidade ambiental. Nós encorajamos que o programa de recomposição manejo das matas ciliares dos córregos rurais do rio Uberabinha seja estendido aos córregos urbanos do município.

Patterns of mollusc distribution in mangroves from the São Marcos Bay, coast of Maranhão State, Brazil / Padrões de distribuição de moluscos em manguezais da Baía de São Marcos, costa do Estado do Maranhão, Brasil

The diversity and distribution of molluscs from the Amazon Coast of Maranhão State, Brazil, are poorly understood. The aim of this study was to investigate how molluscs in two mangrove creeks (Buenos Aires and Tronco) at the São Marcos Bay, coast of the Maranhão State, respond to spatial and temporal variations in the environment. Sampling was performed in the intertidal area along three zones established using a straight line transect of 100 m. Abiotic variables of water and sediment were measured at each creek. We found 5,912 specimens belonging to 23 species and 15 families of epifaunal and infaunal molluscs. The patterns of their distribution in the two creeks were different. Salinity, dissolved oxygen, and rainfall were the main variables that affected the temporal distribution of molluscs. We found low species richness in the overall mollusc composition. Diversity in the Buenos Aires Creek was lower than that observed in the Tronco Creek, possibly because of activities of a port located in proximity to the former. The spatial distribution of molluscs along the zones followed an abundance and diversity gradient, mainly influenced by exposure time during low tide. Port activities may influence the patterns of mollusc distribution in the surrounding mangroves, and we thus highlight the importance of management and monitoring of these areas.

A diversidade e distribuição de moluscos na Costa Amazônica do Estado do Maranhão, Brasil, são pobremente conhecidas. O objetivo deste estudo foi investigar como os moluscos em dois igarapés de manguezal (Buenos Aires e Tronco) na Baía de São Marcos, costa do Estado do Maranhão, respondem a variações espaciais e temporais no ambiente. A amostragem foi conduzida no entre-marés ao longo de três zonas estabelecidas a partir de um transecto em linha reta de 100 m. As variáveis abióticas de água e sedimento foram medidas para cada igarapé. Foram contabilizados 5.912 espécimes pertencentes a 23 espécies e 15 famílias na epifauna e endofauna. Os padrões de distribuição de moluscos foram distintos entre os dois igarapés. Salinidade, oxigênio dissolvido e precipitação foram as principais variáveis que influenciaram a distribuição temporal dos moluscos. Observou-se baixa riqueza de espécies na composição geral de moluscos. A diversidade no igarapé Buenos Aires foi menor do que a observada no igarapé Tronco, possivelmente por causa das atividades portuárias nas proximidades do primeiro. A distribuição espacial vertical de moluscos ao longo das zonas seguiu um gradiente de abundância e diversidade influenciado principalmente pelo tempo de exposição durante a maré baixa. As atividades portuárias podem estar influenciando os padrões de distribuição de moluscos nos manguezais do entorno, portanto destacamos a importância do manejo e monitoramento dessas áreas.

Reef fish community in presence of the lionfish (Pterois volitans) in Santa Marta, Colombian Caribbean / Comunidad de peces arrecifales en presencia del pez león (Pterois volitans) en Santa Marta, Caribe colombiano

Objetive. Fish species community structure and benthic organisms coverage were studied in five localities in Santa Marta where the lionfish is present. Materials and methods. Abundance of fish species, including lion fish, was established using 30 m random visual censuses and video transects; trophic guilds were established according to available references. On the other hand benthic coverage was evaluated using the software Coral Point Count (CPCe) 4.0. Results. Families with higher species numbers were Serranidae, Labridae, and Pomacentridae. Lionfish abundances were low (2.6±2.1 ind/120 m²), but in any case Pterois volitans was observed as the eleventh more abundant species, surpassing species of commercial value such as Cephalopholis cruentata. Species that were found in larger numbers (>100, Thalassoma bifasciatum, Haemulon aurolineatum, Canthigaster rostrata, Abudefduf saxatilis, Chromis cyanea, and Stegastes partitus) were mainly invertebrate eaters, planctivores, and territorial herbivores. Coral coverage showed higher coral percentages in Chengue (69.9%) and Cinto (27.4%), larger sponge percentages in Morro (32.7%); Isla Aguja and Remanso showed the larger figures for abiotic substrate (41.6 and 37%, respectively); corals, sponges, and gorgonians were the components best explaining fish community, but not for the lion fish, which inhabit all studied reef formations. Conclusions. Lion fish is ranked between the 20 more abundant species, with none commercially important species larger, hence no species may qualify as a natural control. Lion fish has as well become a relatively abundant species in Santa Marta reefs, independent of benthic coverage.

Objectivo. Se estudió la estructura de especies de la comunidad íctica y se evaluó la cobertura de organismos bentónicos en cinco localidades en Santa Marta, Colombia con presencia del pez león. Materiales y métodos. Se estimó la abundancia a través de censos visuales y video transectos de 30 m y se estableció el gremio trófico de cada especie según literatura. El sustrato se cuantificó con el software Coral Point Count (CPCe) 4.0. Resultados. Las familias con más especies fueron Serranidae, Labridae y Pomacentridae y, aunque su abundancia promedio fue baja (2.6±2.1 ind/120 m²), Pterois volitans fue la undécima especie más abundante, superando a peces comerciales como Cephalopholis cruentata. Las especies más abundantes fueron invertívoros, planctívoros y herbívoros, tales como Thalassoma bifasciatum, Haemulon aurolineatum, Canthigaster rostrata, Abudefduf saxatilis, Chromis cyanea y Stegastes partitus. Se encontró mayor porcentaje de coral en Chengue (69.9%) y Cinto (27.4%) y de esponjas para Morro (32.7%); para Isla Aguja y Remanso predominó el componente abiótico (41.6 y 37%, respectivamente). Corales, esponjas y gorgonias fueron los componentes que mejor explicaron la comunidad íctica, aunque no para el pez león que habita todas las formaciones arrecifales. Conclusiones. El pez león se ubica entre las 20 especies de peces más abundante, con ninguna especie de importancia comercial en los sitios muestreados que lo supere en talla y que pudiera ser un control natural del invasor. Igualmente, se ha convertido en una especie relativamente abundante en los arrecifes samarios sin importar los atributos del fondo.

From baby to adult: ontogenetic series of nine species of Ophiuroidea from Atlantic Southwestern / De bebé a adulto: serie ontogenética de nueve especies de Ophiuroidea del Atlántico sudoccidental

Abstract The post-metamorphic stage is essential in the life history of marine invertebrates. During this period, animals are more vulnerable and suffer high mortality, which influences the distribution and abundance of adult populations. It is also during this period that major morphological changes happen in the individuals, complicating their taxonomic identification. The juvenile ophiuroids dominate the meiofauna in certain times of the year and at some places. However, they are ignored by most ecological studies due to identification difficulties. Here we describe the ontogeny of nine deep-sea species from the Southeast and South regions of Brazil, with the first record of morphological modifications for eight of them. Most organisms were collected 60 to 800 m deep, between December 1997, January, 1998 and March, 1998, during the REVIZEE-Score South / Benthos program. We also included additional material from the Zoology Museum of Unicamp (ZUEC). For descriptions and identifications of the different stages, the specimens were dried and photographed. The juveniles were identified by "backwards" process through the growth series of adults to smaller individuals, a backwards method that was successful in previous studies. Some individuals were mounted on aluminum stubs for scanning electron microscopy. The species were: Ophiacantha pentacrinus (Ophiacanthidae), Ophiomastus satelitae, Ophiomusium acuferum, Ophiomusium eburneum, Ophiomisidium tommasii, Ophiura ljungmani, Ophiura clemens (Ophiuridae), Amphiura complanata (Amphiuridae) and Ophiothrix rathbuni (Ophiotrichidae). Many species could be identified since their most juvenile stage. Some structures remain almost unaltered during the whole life. Rev. Biol. Trop. 63 (Suppl. 2): 361-381. Epub 2015 June 01.

Resumen La etapa post-metamórfica es esencial en la historia de vida de los invertebrados marinos. Durante este período, los animales son más vulnerables y sufren una elevada mortalidad, que influye en la distribución y abundancia de las poblaciones de los adultos. También es durante este período cuando grandes cambios morfológicos ocurren en los individuos, lo que complica su identificación taxonómica. Los ofiuroideos juveniles son el componente principal para la mayor parte de la composición de la meiofauna en ciertas épocas del año y en algunos lugares. Sin embargo, son ignorados por la mayoría de los estudios ecológicos debido a las dificultades de identificación. De esta manera, la descripción de las fases juveniles presenta mayor importancia, sobre todo en estudios relacionados con la dinámica poblacional y de composición de fauna. Este trabajo tiene como objetivo describir la ontogenia de nueve especies de aguas profundas de las regiones Sudeste y Sur de Brasil, siendo el primer registro en la literatura sobre cambios morfológicos -a partir del crecimiento- para ocho de ellos. La mayoría de los organismos se tomaron en el intervalo de 60 a 800 m de profundidad, entre diciembre de 1997, enero de 1998 y marzo de 1998, durante el programa REVIZEE Sur-Score / Bentos. También se incluyen en este estudio material adicional del Museo de Zoología de la Unicamp (ZUEC). Para las identificaciones y descripciones de las diferentes etapas, las muestras se secaron y fueron fotografiadas. Los juveniles fueron identificados por "al revés" el proceso de crecimiento a través de la serie desde adultos hasta los individuos de menores tallas, una metodología exitosa en estudios anteriores. Las especies seleccionadas para la descripción de la serie de crecimiento fueron escogidas de acuerdo a su abundancia relativa en diferentes etapas de desarrollo. Algunos individuos fueron montados en tacos de aluminio para la microscopía electrónica de barrido. Las especies se estudiadas fueron: Ophiacantha pentacrinus (Ophiacanthidae), Ophiomastus satelitae, Ophiomusium acuferum, Ophiomusium eburneum, Ophiomisidium tommasii, Ophiura ljungmani, Ophiura clemens (Ophiuridae), Amphiura complanata (Amphiuridae) y Ophiothrix rathbuni (Ophiotrichidae). El análisis del desarrollo post-metamórfico de los individuos reveló que muchas especies podrían ser identificadas desde sus etapas más juveniles, sobre todo a partir de caracteres morfológicos externos. Este estudio nos permite sostener que algunas estructuras permanecen casi inalteradas durante toda la vida del organismo, mientras que otras están sujetas a transformaciones. De este modo, se contribuye al conocimiento más amplio de algunas especies de ofiuroideos, con relación a la caracterización de sus diferentes etapas de desarrollo.

Macrofauna bentónica de las playas de arena del Área de Conservación Osa, Puntarenas, Pacífico Sur de Costa Rica / Benthic macrofauna found in Sandy beaches from Osa Conservation Area, Puntarenas, Southern Pacific coast of Costa Rica

Resumen Se describe la diversidad y composición de especies las playas de arena del Pacífico Sur de Costa Rica. En las playas de arena de la región, se colectó individuos de la infauna por medio de barrenos. Para la zona de entre mareas arenosa el número de especies estrictamente marina varió de 5 a 13 taxones, número que es intermedio con los reportados previamente para estos ambientes en Costa Rica. En la zonas de arena, el supralitoral lo dominó el isópodo Cirolana salvadorensis, mientras nereidos y un gusano de la Familia Pisionidae dominaron en el infralitoral. Otros organismos encontrados en las playas fueron cangrejos del género Uca, cangrejos anomuros (Emerita), galletas de mar (Mellita longifissa) y varios grupos de poliquetos tubícolas permanentes o temporales de la familias Onuphidae, Spionidae, Magelonidae y Glyceridae. Las playas mostraron variación en su fauna atribuible en ciertos casos a la exposición al oleaje, teniendo menos fauna en las playas más reflectivas. Se mencionan acitivades humanas que pueden explicar la baja riqueza de especies encontrada en algunas de las playas analizadas.

Abstract The diversity and species composition of the intertidal sandy beaches in the southern Pacific coast of Costa Rica were studied by means of cores collected along perpendicular transects to the beaches. The numbers of strictly marine species varied between 5 to 13 taxa, representing an intermediate value compared to those previously reported for these environments in Costa Rica. The isopod Cirolana salvadorensis was the dominant species in the supralittoral zone, whereas polychaete worms belonging to the families Nereididae and Pisionidae dominated the low intertidal zone. Others organisms collected in the beaches were the crabs of the genus Uca, anomurans crabs (Emerita), sand dollars (Mellita longifissa) and several taxa of polychaete tubeworms, such as the Onuphidae, Spionidae, Magelonidae, and Glyceridae. The high faunal difference among the sites is possibly explained by their exposure to the wave energy, with fewer individuals in the more reflective beaches. In addition, human activities might also be responsible for the low infaunal diversity found in some of these beaches. This is the first effort to describe the benthonic fauna of beaches from this area. Rev. Biol. Trop. 63 (Suppl. 1): 273-285. Epub 2015 April 01.

Bomb-cratered coral reefs in Puerto Rico, the untold story about a novel habitat: from reef destruction to community-based ecological rehabilitation / Los arrecifes de coral con craters-bomba en Puerto Rico, la historia no contada sobre un hábitat inusual: desde la destrucción de arrecifes hasta la rehabilitación ecológica basada en la comunidad

Ecological impacts of military bombing activities in Puerto Rico have often been described as minimal, with recurrent allegations of confounding effects by hurricanes, coral diseases and local anthropogenic stressors. Reef craters, though isolated, are associated with major colony fragmentation and framework pulverization, with a net permanent loss of reef bio-construction. In contrast, adjacent non-bombarded reef sections have significantly higher benthic spatial relief and biodiversity. We compared benthic communities on 35-50 year-old bomb-cratered coral reefs at Culebra and Vieques Islands, with adjacent non-impacted sites; 2) coral recruit density and fish community structure within and outside craters; and 3) early effects of a rehabilitation effort using low-tech Staghorn coral Acropora cervicornis farming. Reef craters ranged in size from approximately 50 to 400m² and were largely dominated by heavily fragmented, flattened benthos, with coral cover usually below 2% and dominance by non-reef building taxa (i.e., filamentous algal turfs, macroalgae). Benthic spatial heterogeneity was lower within craters which also resulted in a lowered functional value as fish nursery ground. Fish species richness, abundance and biomass, and coral recruit density were lower within craters. Low-tech, community-based approaches to culture, harvest and transplant A. cervicornis into formerly bombarded grounds have proved successful in increasing percent coral cover, benthic spatial heterogeneity, and helping rehabilitate nursery ground functions.

Los impactos ecológicos de las actividades militares de bombardeos en Puerto Rico se han descrito a menudo como mínimos, con recurrentes denuncias al confundir efectos por huracanes, enfermedades de corales y estresores antropogénicos locales. Los cráteres de arrecife, aunque aislados, están relacionados con una alta fragmentación de la colonia y pulverización del contorno, con una pérdida neta permanente de arrecife en bio-construcción. En contraste, secciones adyacentes de arrecife no bombardeado tienen mayor biodiversidad y mayor relieve espacial bentónico. Comparamos las comunidades bentónicas en cráteres-bomba de arrecifes de coral con 35-50 años de antigüedad en las islas de Vieques, Puerto Rico, en comparación con los sitios adyacentes no impactados; 2) la densidad de reclutamiento de coral y estructura de la comunidad de peces dentro y fuera de los cráteres; y 3) impactos preliminares de un esfuerzo de rehabilitación basado en la comunidad arrecifal usando tecnología simple con el cultivo del coral Staghorn Acropora cervicornis. Los cráteres de arrecife se distancian en tamaño de aproximadamente 50 a 400m² y fueron dominados ampliamente por fragmentos de bentos aplanado, con una cubierta de coral generalmente por debajo de 2% y el predominio de taxones no constructores de arrecifes (es decir, tapetes de algas filamentosas, macroalgas). La heterogeneidad espacial bentónica fue significativamente menor dentro de cráteres que también resultaron en un reducido valor funcional como tierra de vivero de peces. La riqueza de especies de peces, abundancia y biomasa y densidad coral recluta fueron significativamente menores dentro de cráteres. Tecnología simple, basada en los enfoques de cultivo de comunidad, la cosecha y transplante de A. cervicornis en terrenos anteriormente bombardeados han demostrado un éxito al aumentar el porcentaje de cobertura de coral, la heterogeneidad espacial bentónica y ayudando a rehabilitar funcionalmente la tierra para vivero.

Macrofauna edáfica em diferentes coberturas vegetais / Edaphic macrofauna in different plant covers

A macrofauna edáfica desempenha papel importante na ciclagem de nutrientes e melhora as propriedades químicas e físicas do solo. O objetivo do presente trabalho foi avaliar a biodiversidade da macrofauna edáfica em área com a cultura do eucalipto, cafeicultura e mata ciliar, Campos Gerais - MG. Os tratamentos constaram da coleta da macrofauna da serapilheira e solo em coberturas vegetais (café, eucalipto e mata ciliar) no período do inverno e verão. As avaliações foram realizadas pela frequência de indivíduos nos diferentes grupos taxonômicos, densidade e riqueza, índice de Shannon (H') e Pielou (J'). Na serapilheira foi observada a presença das ordens Arachinida, Coleoptera e Hymenoptera nas diferentes áreas e épocas. No solo, em todos os sistemas de manejo e épocas, foi observada a presença do grupo Oligochaeta, sendo encontrados de maneira predominante na mata ciliar. A maior riqueza de ordens e população de indivíduos por metro quadrado foi encontrado no solo de mata ciliar no período de verão. O melhor índice de Shannon (H') foi encontrado no solo da mata ciliar no inverno e na serapilheira da cultura do cafeeiro no verão. O índice de Pielou (J') apresentou melhores resultados nos diferentes sistemas de manejo de solo no período de inverno. A mata ciliar é a área de maior biodiversidade de macrofauna edáfica.

The edaphic macrofauna plays important role in the cycling of nutrients and improves the chemical and physical properties of soil. The purpose of this study was to evaluate the biodiversity of edaphic macrofauna in area with of coffee and eucalyptus crops and riparian forest, Campos Gerais - MG. The treatments consisted of edaphic macrofauna samples in different plant covers (coffee, eucalyptus and riparian forest) in winter and summer epochs. In the leaf litter was observed the presence of arachnids, coleopteras and hymenopteras in different areas and epochs. On the soil, all systems of management and epochs, was observed the presence of oligochaetas, being found so prevalent in the riparian forest. The greatest wealth of orders and individuals per square meter were found in summer in riparian forest soil. The best of Shannon index (H') was found in the soil of the forest and in the leaf litter of the coffee crop in winter and summer respectively. The index of Pielou (J') showed the best results in different soil management systems in winter period. In the leaf litter, the Pielou index showed good performance in different areas and epochs. The riparian forest is the area of highest biodiversity of soil macrofauna.

A comparison of visual and collection-based methods for assessing community structure of coral reef fishes in the Tropical Eastern Pacific / Una comparación de métodos visuales y basados ​​en colecciones para evaluar la estructura de la comunidad de peces de arrecifes de coral en el Pacífico Oriental Tropical

Gorgona Island, the major insular area in the Colombian Pacific Ocean, is characterized by a remarkably high biological and ecosystem diversity for this area of the world. Coral reefs are well developed and their fish communities have been described using conventional visual surveys. These methods, however, are known to be biased towards detecting larger and more mobile species, tending to ignore small and cryptobenthic species. The two main objectives of this study were to describe the assemblage structure of the cryptobenthic fish fauna and estimate the extent to which this fauna is underestimated by visual surveys.At the beginning and the end of the warm season, we compared the cryptobenthic fish assemblage recorded using visual surveys against the one recorded using “enclosed anesthetic/rotenone samples” on isolated coral colonies (N=54 beginning of warm season; N=17 end of warm season). The crypthobenthic fish fauna associated to coral colonies was characterized by small body sizes and was composed mainly by species of the families Antennaridae, Blennidae, Gobiidae, Labrisomidae, Muraenidae, Serranidae, Scorpaenidae and Syngnathidae. Conventional visual surveys underestimated overall species richness by 28-36% and number of individuals by 16-35%. Noteworthy, four species recorded during this study using “enclosed anesthetic/rotenone samples” were new records for Gorgona Island. Although both sampling methods can detect a largely overlapping group of species, the “enclosed anesthetic/rotenone samples” method was able to detect more individuals and species, including several species that visual surveys fail to detect. Although this study is the first effort to describe the cryptobenthic fish assemblage associated to coral reefs in the Tropical Eastern Pacific, our results suggest that these assemblages are an important component of the reef fish community in the region in terms of biodiversity and functional roles. Rev. Biol. Trop. 62 (Suppl. 1): 359-371. Epub 2014 February 01.

Métodos de muestreo convencionales (censos visuales) usados en el estudio de peces arrecifales han llevado a una constante subestimación de la riqueza de especies, ya que estos tienden a ignorar especies pequeñas y crípticas. En este estudio describimos la estructura del ensamblaje de peces criptobentónicos en Isla Gorgona, Colombia y estimamos el grado en que este ensamblaje es subestimado al usar censos visuales. Al comienzo y al final de la estación cálida comparamos la capacidad de detección de censos visuales vs “muestreos cerrados con anestésico/rotenona” (N=54 comienzo; N=17 final). La fauna criptobentónica se caracterizó por mantener individuos de tamaños corporales pequeños, pertenecientes principalmente a las familias Antennaridae, Blennidae, Gobiidae, Labrisomidae, Muraenidae, Serranidae, Scorpaenidae and Syngnathidae. Los censos visuales subestimaron la riqueza de especies en un 28-36% y el número de individuos en un 16-35%. Aunque un gran número de especies son detectadas usando ambos métodos, los “muestreos cerrados con anestésico/rotenona” detectan un mayor rango de especies. Este estudio, el primer esfuerzo para describir el ensamblaje de peces criptobentónicos asociados a arrecifes coralinos en Colombia, sugiere que la fauna criptobentónica puede ser un componente importante de la comunidad arrecifal en términos de biodiversidad y papel funcional.

Fish community structure on coral habitats with contrasting architecture in the Tropical Eastern Pacific / Estructura de la comunidad de peces en hábitats de coral con arquitectura contrastante en el Pacífico Oriental Tropical

Reefscape architecture, shaped by dominant coral morphologies, can play a major role in determining the structure and composition of fish assemblages by affecting niche and resource availability and mediating interspecific interactions. To explore the role of dominant coral morphologies on reef fish communities, we carried out a comparative study of the fish community associated with a Massive Coral Community (MCC) and a Branching Coral Community (BCC) at Gorgona Island, Tropical Eastern Pacific (TEP). On each community, the benthic substrate was assessed through the “chain transect method” while the fish assemblage was evaluated through visual surveys on belt transects. We found differences between both fish assemblages in terms of the abundance, diversity (H’), and evenness (J’). The BCC, despite being formed by morphologically complex pocilloporid colonies, had a simple and relatively flat architecture that attracted principally small and territorial fishes. Significant higher abundances of Chromis atrilobata and Thalassoma lucasanum at the BCC boosted the total fish abundance but caused low fish evenness and diversity. Conversely the MCC, composed of massive coral species with considerable sizes and diversity of shapes, held a complex and high-relief reefscape capable of sustaining a more diverse and even fish community, although with the same species richness as the BCC. Fishes with large sizes, roving behavior and piscivore-feeding preferences were especially attracted to the MCC. Although, massive coral species are important in determining a diverse and complex reefscape architecture, both dominant coral morphologies (massive and branching) attract and provide resources to different types of fish according to their size, mobility and trophic group. Our results suggest that a loss of massive coral species and a community shift towards stress-resistant taxa (such as Pocillopora spp.), could alter the structure and function of fish assemblages in the TEP due to the habitat loss for large, mobile and piscivore species. Rev. Biol. Trop. 62 (Suppl. 1): 343-357. Epub 2014 February 01.

La arquitectura del paisaje arrecifal, definida por la morfología de los corales dominantes, puede desempeñar un papel importante en la estructura y composición de las comunidades de peces al afectar la disponibilidad de nichos y recursos y modificar las interacciones interespecíficas. Hicimos un estudio comparativo entre la comunidad de peces asociada a una comunidad de corales masivos (CCM) y a una de corales ramificados (CCR) en la isla Gorgona, Pacífico Oriental Tropical. En cada formación coralina, el sustrato bentónico se evaluó a través de “transectos de cadena”, mientras que la comunidad de peces se valoró con el uso censos visuales en transectos de banda. Hubo diferencias en la abundancia, diversidad (H’) y equitatividad (J’) de las dos comunidades de peces. La CCR, a pesar de estar formada por colonias morfológicamente complejas de corales pocillóporidos, presentó una arquitectura simple y relativamente plana que atrajo principalmente peces territoriales y de talla pequeña. Abundancias significativamente altas de Chromis atrilobata y Thalassoma lucasanum en la CCR, aumentaron la abundancia total de peces, pero ocasionaron una baja diversidad y equitatividad de la comunidad. Por el contrario, la CCM constituida principalmente por especies de corales masivos con diversos tamaños y formas, presentó una arquitectura compleja y de alto relieve capaz de mantener una comunidad de peces mucho más diversa y equitativa, aunque con la misma riqueza de especies de peces que la CCR. Los peces de gran talla, con comportamiento errante y hábitos carnívoros fueron atraídos a la MCC. En general, nuestro estudio evidenció que aunque las especies de coral con crecimiento masivo son importantes en la formación de una arquitectura compleja, cada una de las morfologías de coral dominante (masivo y ramificado) atrae y brinda recursos a distintos grupos de peces según su tamaño y grupo trófico. La pérdida de corales masivos o un cambio en la comunidad hacia corales pocilóporidos (resistentes al estrés) podrían alterar la diversidad y función comunitaria de peces en el Pacífico Oriental Tropical (POT) debido a la pérdida de hábitat para las especies grandes, móviles y carnívoras.