La conservación de los arrecifes coralinos radica en el manejo adecuado de estos ecosistemas marinos, sin embargo es necesario dotar de información biológica para saber que se debe proteger, por lo ...tanto, disponer con descripciones de las comunidades coralinas contribuye en gran medida a formular estrategias de manejo eficaces. Bajo este contexto se describe la distribución de los hábitats bentónicos dominantes de la planicie del arrecife Enmedio. Durante el periodo noviembre 2014-abril 2016 se recabaron datos geográficos de los componentes bentónicos de la llanura arrecifal mediante buceo libre, esencialmente la información espacial se obtuvo a partir de registros fotográficos utilizando una cámara digital con receptor de posicionamiento global (GPS), con los datos recabados se generó un mapa temático mediante el método kriging simple. Las descripciones de los hábitats arrecifales se complementó con base al número de ensamblajes de especies principalmente de macroinvertebrados bentónicos y peces. Básicamente se diferencian ocho hábitats bentónicos en la planicie del arrecife Enmedio, fundamentalmente están constituidos por las especies Acropora palmata, Millepora alcicornis, Orbicella annularis, Pseudodiploria clivosa, Porites furcata, Palythoa caribaeorum, Eunicea flexuosa y por dos fondos bentónicos: cresta arrecifal y escombros. Los hábitats bentónicos: O. annularis y de A. palmata presentaron un mayor número de especies asociadas, mismas que comparten mayor semejanza en el ensamblaje de especies en comparación al resto de los componentes bentónicos. La distribución que manifiestan los componentes bentónicos con respecto a la cresta arrecifal es parecido al de otras regiones del Atlántico. ABSTRACT The conservation of the coral reefs lies in the proper management of these marine ecosystems, however it is necessary to provide biological information to know what we must protect. Therefore, in order to formulate effective management strategies, descriptions of coral communities are needed. Under this context, the distribution of dominant benthic habitats of the Enmedio reef’s plateau is described. Geographical data of benthic components in the reef lagoon were recorded by free diving during the November 2014-April 2016 period. The spatial information was obtained essentially from photographic records using a digital camera with a receiver using global positioning system (GPS). A thematic map was generated with the data obtained through the simple kriging method. The descriptions of the reef landscapes were complemented by a number of species assemblage, consisting mainly of the benthic macroinvertebrates and fish. Eight benthic habitats in the plain of the Enmedio reef are differentiated and represented mainly by the species Acropora palmata, Millepora alcicornis, Orbicella annularis, Pseudodiploria clivosa, Porites furcata, Palythoa caribaeorum, Eunicea flexuosa and two benthic funds: reef crest and debris. The areas of O. annularis and A. palmata are the most important reef landscapes because these species concentrated a greater number of associated species. These zones subsequently share greater similarity in the assemblage of species compared to other benthic components. The distribution of the benthic components is similar to other regions of the Atlantic.
Benthic macroinvertebrates are widely used in evaluations of environmental impact and recommended in biomonitoring, but little used in Brazilian lentic environments. One of the main objectives has ...been to explain and predict the distribution of those species according to environmental characteristics. Thus, the study aims to characterize the predominant fauna of the Lake Figueira sediment and its relationship with organic matter and depth, analyzing seasonal variation in communities and aiming to select bioindicators of the trophic state. Sampling was carried out from January 2008 to January 2009, along the lagoon fetch, with an Ekmann-Birge dredge (area 225 cm²). Taxon richness was not significantly related with depth and organic matter content, but those variables were highly correlated (r = 0.962; r² = 0.926 and p < 0.001). The constant oxygenation of the whole water column allows the occurrence of organisms, independent of depth and organic matter content. Chironomidae was the most abundant taxon and from the frequency of occurrence, abundance and clustering analysis it was possible to select Larsia sp. , Goeldichironomus maculatus, Xenochironomus sp. , Aedokritus sp. Cladopelma forcipis, Cryptochironomus brasiliensis, Nilothauma sp.1 and Caladomyia sp. C, Tanytarsus sp. , Tanytarsus rhabdomantis and Chironomus gr. salinarius as potential indicators related with the spatiotemporal faunal distribution of Lake Figueira.
Macroinvertebrados bentônicos são amplamente utilizados nas avaliações de impacto ambiental e recomendado em biomonitoramento, mas pouco utilizado em ambientes lênticos brasileiros. Um dos principais objetivos tem sido explicar e predizer a distribuição das espécies de acordo com as características ambientais. Assim, o estudo tem por objetivo caracterizar a fauna predominante do sedimento da Lagoa da Figueira e sua relação com a matéria orgânica e profundidade, analisando as variações sazonais nas comunidades e com o objetivo de selecionar bioindicadores do estado trófico. A amostragem foi realizada a partir de Janeiro 2008 a janeiro 2009, ao longo do fetch da lagoa, com uma draga Ekmann-Birge (área 225 cm²). Riqueza de táxon não foi significativamente relacionada com a profundidade e teor de matéria orgânica, mas essas variáveis foram altamente correlacionadas (r = 0,962, r ² = 0,926 e p < 0,001). A constante oxigenação de toda coluna de água possibilita a ocorrência dos organismos independente da profundidade e conteúdo de matéria orgânica. Chironomidae foi o táxon mais abundante e a partir da frequência de ocorrência, abundância e da análise de agrupamento foi possível selecionar Larsia sp., Goeldichironomus maculatus, Xenochironomus sp., Aedokritus sp., Cladopelma forcipis, Cryptochironomus brasiliensis, Nilothauma sp.1, Caladomyia sp. C, Tanytarsus sp., Tanytarsus rhabdomantis e Chironomus gr. salinarius como potenciais indicadores relacionados com a distribuição espaço-temporal da fauna da Lagoa da Figueira.
Tropical Eastern Pacific island streams (TEPis) differ from other neotropical streams in their rainy climate, mixed sedimentary-volcanic geology and faunal composition. Yet, their relationships ...between environmental characteristics and stream biota remain unexplored. We analyzed the environmental subject at three spatial scales using a fully nested sampling design (6 streams, 2 reaches within each stream, 2 habitats within each reach, and 4 replicates per habitat) on Gorgona Island (Colombia). Sampling was carried out in two months with contrasting rainfall during early 2009. We studied the spatial variation of assemblage composition and density along with 27 independent variables within two contrasting rainfall conditions. Five stream-scale variables, two reach-scale variables, and five habitat-scale variables were selected using a Canonical Correspondence Analysis (CCA). A partial CCA showed that the total variance explained was 13.98%, while stream- and habitat-scale variables explained the highest proportion of the variance (5.74 and 5.01%, respectively). Dissolved oxygen (as affected by rainfall), high-density use zone (a management category), and sedimentary geology were the best descriptors of insect assemblages. The two latter descriptors affected fine-scale variables such as total benthic organic matter and gravel substratum, respectively. A Nested ANOVA showed significant differences in total density and richness among streams and habitats, and significant differences between the two sampling months regardless of the spatial scale. The evenness showed a significant stream- and habitat-dependent temporal variability. These results suggested that rainfall regime in Gorgona Island might be a driver of insect assemblage dynamics mediated by water chemistry and substratum properties. Spatial assemblage variability here is greater within habitats (among samples), and a minor fraction occurs at habitat- and stream-scales, while no longitudinal pattern was observed probably due to the short courses. Temporal variability should be further studied relative to rainfall and discharge regimes. Rev. Biol. Trop. 62 (Suppl. 1): 65-83. Epub 2014 February 01.
Increasing anthropogenic pressures urge enhanced knowledge and understanding of the current state of marine biodiversity. This baseline information is pivotal to explore present trends, detect future ...modifications and propose adequate management actions for marine ecosystems. Coralligenous outcrops are a highly diverse and structurally complex deep-water habitat faced with major threats in the Mediterranean Sea. Despite its ecological, aesthetic and economic value, coralligenous biodiversity patterns are still poorly understood. There is currently no single sampling method that has been demonstrated to be sufficiently representative to ensure adequate community assessment and monitoring in this habitat. Therefore, we propose a rapid non-destructive protocol for biodiversity assessment and monitoring of coralligenous outcrops providing good estimates of its structure and species composition, based on photographic sampling and the determination of presence/absence of macrobenthic species. We used an extensive photographic survey, covering several spatial scales (100s of m to 100s of km) within the NW Mediterranean and including 2 different coralligenous assemblages: Paramuricea clavata (PCA) and Corallium rubrum assemblage (CRA). This approach allowed us to determine the minimal sampling area for each assemblage (5000 cm² for PCA and 2500 cm²for CRA). In addition, we conclude that 3 replicates provide an optimal sampling effort in order to maximize the species number and to assess the main biodiversity patterns of studied assemblages in variability studies requiring replicates. We contend that the proposed sampling approach provides a valuable tool for management and conservation planning, monitoring and research programs focused on coralligenous outcrops, potentially also applicable in other benthic ecosystems
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Em ecossistemas lóticos é comum a formação de diferentes mesohabitats intercalados ao longo do rio, como poções, corredeiras e rápidos, frequentemente acompanhados de alterações na estrutura da fauna ...bentônica associada. No trabalho analisamos a fauna de invertebrados bentônicos em rápidos e corredeiras de um trecho de serra do Rio Capivara (Bacia do Médio Rio Tietê). A análise das características ambientais e a coleta da fauna foram realizadas em três corredeiras e três rápidos, em um mês da estação chuvosa (cinco réplicas de cada). Os mesohabitats se diferenciaram quanto ao maior porcentual de blocos nos rápidos e maiores valores de profundidade, correnteza e porcentual de matacões nas corredeiras. Do total de 57 Unidades Taxonômicas Operacionais (UTO’s) amostradas, 75% foram comuns aos dois mesohabitats (Similaridade de Morisita = 0,86). Quando analisado o porcentual de abundância, a similaridade espacial se manteve e dois grupos se sobressaíram em abundância: Hexapoda (>80%, sendo a maioria Ephemeroptera, Diptera e Trichoptera) e Annelida (10%). As análises exploratórias (cluster e NMDS) também apontaram para uma elevada similaridade espacial, porém os resultados da Análise de Similaridade (ANOSIM) indicaram uma diferença significativa entre os mesohabitats (p<0,1%), seja analisando o total de UTO’s ou retirando as UTO’s raras. Cinco grupos tiveram uma maior contribuição para a média de dissimilaridade entre os mesohabitats: Simulium e Baetodes mais abundantes nas corredeiras, Traveryphes, Hagenulopsis e Macrelmis nos rápidos. Assim, os resultados da ANOSIM salientaram a importância do refinamento na identificação para a interpretação mais precisa acerca da relação entre a fauna e a estrutura do habitat.
La zona litoral rocosa esta entre los ambientes físicamente más extremos de la tierra. Los organismos que allí habitan son azotados alternadamente por factores físico-químicos y biológicos. Debido a ...la gran importan- cia ecológica que poseen estos ambientes, se estudió la diversidad, abundancia y distribución de la macrofauna bentónica del litoral rocoso, en la costa norte del estado Sucre, Venezuela. Se realizaron muestreos bimensuales, durante un año. La recolecta del material biológico se realizó de forma manual, dentro de una cuadrícula de 0.25m², en la zona litoral (supra, medio e infralitoral). Los organismos fueron preservados en formalina al 10% para su posterior identificación y análisis (parámetros ecológi- cos y prueba Kruskal-Wallis a la abundancia y diversidad). Se obtuvieron un total 19 020 organismos (86spp.), en 8 filos, 45 familias y 47 géneros. Los moluscos fueron los más abundantes y diversos (58 spp.), seguido de los artró- podos (12spp.), anélidos (7spp.), equinodermos (5spp.), y cnidarios, sipuncúlidos, nemertínidos y urocordados (1sp.). Los resultados encontrados, coincidieron con el esquema universal de zonación de Stephenson & Stephenson (1949). Las localidades de Río Caribe y Boca de Río presentaron los valores más altos de los parámetros ecológicos y Playa Grande los más bajos. Estadísticamente se observaron diferencias en la abundancia y diversidad de la macrofauna, entre las tres zonas. La poca información de la composición y distribución macrobentónica del litoral rocoso, impide una mejor comparación, no obstante los resultados contri- buyen al conocimiento de la biodiversidad marina en esta región venezolana.
The source and potential risks of trace metals in settling material collected with sediment traps in the Uruguay River were evaluated utilizing enrichment factors (EF), sediment quality guidelines ...(SQG) and speciation using a 4-step sequential extraction procedure. The total organic carbon content of the settling material was relatively high and homogeneous (2.5 ± 0.3 %) and showed no correlation with the metal concentrations. Total trace metal concentrations decrease from Fe (48,969 ± 7380 µg g
−1
), Mn (1859 ± 233 µg g
−1
), Zn (84 ± 7.6 µg g
−1
), Cu (56 ± 6.9 µg g
−1
), Cr (19 ± 2.7 µg g
−1
), Ni (16 ± 2.0 µg g
−1
) and Pb (13 ± 1.2 µg g
−1
). The average EF of Zn, Cr, Ni and Pb are below 1.5 indicating natural sources, whereas those of Cu and Mn are consistently higher (EF > 2) insinuating some anthropogenic influence. Consistently, Cu concentrations duplicated the SQG (35.7 μg g
−1
) suggesting that adverse biological effects may be observed occasionally. However, speciation results revealed that most metals are associated with the residual fraction, strongly linked to the mineral matrix, and therefore unavailable to aquatic organisms. The sole exception is Mn which is mainly found in the non-residual fractions (∑F1 − F3 = 82 %). Trace metal mobility/bioavailability decreased from Mn (82 %) ≫ Pb (37 %) > Cr (26 %) ~ Ni (25 %) > Zn (20 %) > Cu (14 %) > Fe (10 %). These results demonstrate the utility of metal speciation studies to assess the real risk for aquatic organisms of high Cu concentrations, but associated to relatively immobile fractions of reduced bioavailability.
Studies of the bycatch associated to the shrimp trawling fishery in the Pacific coast of Costa Rica do not assess small organisms (< 10 cm TL) and non-dominant species (< 0.1% of total catch). There ...is a void in assessing the maintenance of the ecology and ecosystem on which the fishery depends. Furthermore, the Constitutional Court of Costa Rica prohibited the renewal of existing and the issuing of new shrimp bottom-trawl licenses, indicating the necessity of more scientific information on the impacts of this fishery. We present the results of a 23-month study of the shrimp bottom-trawl fishery performed between 50 and 350 m deep in the Pacific coast of Costa Rica. A total of 109 hermit crabs were collected (six species and two families). Paguristes cf. holmesi was the most common species. Zone II presented the highest species richness and abundance. Most specimens (81.8 %) were caught in shallower waters (50-149 m). More than 45% of the trawls presented hermit crabs. It is imperative to further assess the trawling effects on non-commercial benthic fauna and changes on predator-prey relationships before issuing new shrimp licenses
Se presenta el registro de las diatomeas epilíticas de los ríos Dolores y Laja, localizados en la cuenca alta del río Laja, Guanajuato, México. Las muestras se recolectaron en las temporadas ...seca-fría (enero) y lluviosa (octubre) del 2011. Se identificaron 173 taxa infragenéricos, de los cuales 7 son nuevos registros para México: Fallacia monoculata, Hantzschia abundans, Navigiolum uruguayense, Neidium bisulcatum, Nitzschia solita, Planothidium incuriatum y Sellaphora bacilloides; cabe mencionar que Navigiolum es nuevo registro a nivel genérico. Además, 3 especies son nuevos registros para el estado de Guanajuato: Gomphonema laticollum, G.subclavatum y Gomphosphenia lingulatiformis. Se encontraron formas teratológicas en 6 especies con abundancias relativas que variaron de 0.8 a 8.3%, siendo estas formas más abundantes en los sitios con mayores concentraciones de nutrientes.
This study investigates the epilithic diatoms from the Dolores and Laja Rivers, located within the Upper Laja River Basin, Guanajuato, Mexico. The samples were collected during the cold-dry (January) and rainy (October) seasons of 2011. One-hundred seventy three infrageneric taxa were identified, 7 of which are new records for Mexico: Fallacia monoculata, Hantzschia abundans, Navigiolum uruguayense, Neidium bisulcatum, Nitzschia solita, Planothidium incuriatum and Sellaphora bacilloides; it is worth mentioning that Navigiolum is a new record at the genus level. Furthermore, 3 species are new records for the state of Guanajuato: Gomphonema laticollum, G.subclavatum and Gomphosphenia lingulatiformis. Teratological forms of 6 species were also found in the sampling sites with higher nutrient concentrations, with relative abundances varying from 0.8 to 8.3%.
Entre febrero y septiembre de 2011, se tomaron muestras de sustrato blando en aguas someras, en tres sectores de un tramo rural del río Bogotá, ubicado en el área de Cajicá (Cundinamarca). Dada la ...importancia del río para la Sabana de Bogotá, el objetivo fue evaluar la calidad del agua, con base en algunas variables abióticas, los macroinvertebrados bentónicos y los índices BMWP/Col. y ASPT. No se observaron diferencias importantes entre los tres sectores de muestreo, pero sí variaciones cronológicas, asociadas a la influencia de las lluvias, intensificadas por un episodio moderado de La Niña. De este modo, las precipitaciones y el perfil limnológico, se relacionaron con la abundancia y la composición taxonómica de los invertebrados. Un sustrato arenoso-limoso favoreció la abundancia de Tubificidae (72,12%) y Chironomidae (23,43%), por su adaptabilidad a cargas orgánicas y de detritus altas y concentraciones bajas de O2. Estos taxa, junto con Physidae, Glossiphoniidae y Tipulidae, principalmente, indicaron contaminación moderada en los tres sectores (BMWP/Col. A=48, B= 48, C= 43) y eutrofización, como consecuencia del impacto humano (aguas residuales y actividades agropecuarias), que afectan las aguas del río y su biota.
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