RESUMO

Non-indigenous species (NIS) have the potential to colonize and become established in a wide range of coastal habitats. Species with broad environmental tolerances can quickly adapt to local conditions and expand their niches along environmental gradients, and even colonize habitats with extreme abiotic conditions. Here we report and document the distribution of eight marine NIS (four seaweed and four invertebrate species) found in tidepools along a 3000 km latitudinal gradient along the Pacific coast of Chile (18.4°S to 41.9°S). The seaweed NIS Codium fragile, Capreolia implexa, Schottera nicaeensis and Mastocarpus latissimus were mostly distributed towards high latitudes (i.e., more southerly locations), where temperatures in tidepools were low. The invertebrate NIS Anemonia alicemartinae, Ciona robusta, Bugula neritina and Bugulina flabellata were more common towards low latitudes, where high temperatures were registered in the tidepools. Across the intertidal gradient, seaweed NIS were mostly found in pools in the mid and low intertidal zone, while invertebrate NIS occurred mostly in pools from the mid and upper intertidal zones. The realized niche spaces of NIS (based on the Outlying Mean Index, OMI) in the study area were mainly influenced by environmental conditions of temperature and salinity (along the latitudinal and intertidal gradients), while other tidepool characteristics (depth, surface area, exposition, and complexity) only had minor effects. Five of the eight NIS exhibited a realized niche space coinciding with the average tidepool environmental conditions, while marginal niches were occupied by species with affinities for specific temperatures and salinities along the latitudinal and intertidal gradients. Our results indicate that physiological tolerances to environmental factors play a fundamental role in the distribution of seaweed and invertebrate NIS in tidepools along the Chilean coast. This study confirms that tidepools offer suitable conditions for some seaweed and invertebrate NIS, potentially facilitating their invasion into new natural habitats.

Assuntos

RESUMO

One of the most important factors regulating the distribution and abundance of seaweeds is desiccation, triggered mainly by tidal changes and climatic variation. Porphyra and Pyropia species have evolved multiple strategies to tolerate desiccation stress; however, how these tolerance strategies differ in these species inhabiting different latitudes is still unknown. In this context, we analyzed, in situ, the physiological responses of these species (collected from 18° S to 41° S along the Chilean coast) to desiccation stress using biochemical and molecular analyses. The hyper-arid terrestrial climate of northern Chile, with high evaporation and lack of constant rain determines a very steep increase in desiccation stress in the upper intertidal during low tide for these species. Accordingly, the results showed that, in comparison with the southernmost populations, the Porphyra/Pyropia species from the north zone of Chile (18°-30° S) exhibited higher contents of lipoperoxide and carbonyls (1.6-1.9 fold) together with higher enzymatic activities, including ascorbate peroxidase, catalase, peroxiredoxin, and thioredoxin (2-3-fold). In addition, a substantial expression of cat, prx, and trx transcripts during desiccation was demonstrated, mainly in the northernmost populations. These results provide evidence of (i) significant activation of antioxidant enzymes and transcripts (principally cat and prx); (ii) participation of phenolic antioxidant compounds as a highly plastic physiological strategy to cope with desiccation; and (iii) the activation of the tolerance responses was affected by species latitudinal distribution. Thus, for the first time, this study integrated the biochemical and genetic responses of diverse Porphyra/Pyropia species to better understand their physiological dynamics of tolerance over a wide latitudinal range.

RESUMO

A screening was undertaken of the native flora of Chile excluding Pteridophyta, Cactaceae and Poaceae the study included 396 species. Alkaloids were found in 189 species, the highest concentration being 3 mg/g dry tissue. A table was produced listing all species collected and specifying the subset containing alkaloids, the species with a particularly high alkaloid content and also the endemic species within this latter set. Alkaloid concentration as well as presence or absence data in different vegetational subregions correlated with mean collection latitude, under the limitations imposed by the relationship between alkaloid concentration and species lineage. In practical terms, the results indicate that in studies aimed at identifying alkaloids in the native flora of Chile, plant collections should take into consideration the promising species listed in the table and take place at the lowest possible latitude if the chance of finding alkaloids and the yield of isolated alkaloids are to be maximized.

Se muestreó un conjunto de 396 especies de la flora nativa de Chile (excluyendo Pteridophyta, Cactaceae y Poaceae), encontrándose alcaloides en 189 de ellas (concentración máxima: 3 mg/g de tejido seco). Se generó una tabla que contiene todas las especies analizadas y especifica aquellas que contienen alcaloides, aquellas que los contienen en altas concentraciones y, entre estas últimas, aquellas que son endémicas. La concentración de alcaloides y también los datos de presencia/ausencia correlacionaron con la latitud media de colecta, bajo las limitaciones impuestas por la relación entre concentración de alcaloides y linaje de la especie. En términos prácticos, los resultados señalan que en estudios que apunten a la identificación de alcaloides en la flora nativa de Chile la colecta de plantas debería tomar en consideración las especies promisoras incluídas en la tabla y ser realizada a la latitud más baja posible dentro del rango de distribución de la especie, maximizando así la probabilidad de encontrar alcaloides en altas concentraciones.

Assuntos

RESUMO

Hermit crabs (Anomura: Paguroidea) distribution patterns in the Colombian Caribbean Sea. Hermit crabs represent the marine life in the Colombian Caribbean, and are important for the dynamic equilibrium maintenance in ecosystems, the ecological interactions and their impact on food web stability. Generally, in order to come up with some conservation strategies, strong bio-geographical information is needed for policies definition. With this aim, this study analyzed the distribution patterns of hermit crabs in the Colombian Caribbean Sea, through classification and spatial ordination multivariate analyses, using historical records from years 1916 to 2006. Besides, the world distribution of Colombian species and their geographic affinity in the Caribbean and Western Atlantic were identified. The results show deep differences between coastal and continental slope faunas, and latitudinal differences in the assemblages, with the identification of three groups: Northeast, Center and Southwest. The differences in faunal composition that support these three groups were determined. Based on maps of the Colombian marine ecosystems, it was found that the main factors affecting the distribution of hermit crabs were the Caribaná slope (depth), water-mass temperature, Guajira sea-grass beds, and particular conditions of “Coralline Archipelagos” and “Darién” eco-regions. Colombian hermit crab fauna is more related to the North Atlantic and the Antilles, than to the South Atlantic and the Gulf of Mexico. Additionally, geographical sub-provinces in which Colombia is included, these were found as transition zones among Northern and Austral subprovinces of the Greater Caribbean.

Los cangrejos ermitaños son un grupo representativo de la fauna marina del Caribe colombiano, además, son importantes en el mantenimiento del equilibrio dinámico, en los ecosistemas por sus interacciones ecológicas y también por el impacto en la estabilidad de las redes tróficas. Sus patrones de distribución se identificaron mediante análisis multivariados de clasificación y ordenación espacial, se usaron registros históricos desde 1916 hasta el 2006. Los resultados indican diferencias por profundidad entre la fauna costera y la del talud continental y diferencias en la distribución latitudinal, en donde se encontraron tres grupos: Noreste, Centro y Suroeste, sustentados por diferencias en la composición faunística. Con base en los mapas de ecosistemas marinos de Colombia, se determinó que los principales factores que afectan su distribución son la influencia del talud Caribaná (profundidad), la temperatura de las masas de agua, las praderas de pastos marinos de la Guajira y las condiciones particulares de las ecorregiones Archipiélagos coralinos y Darién. Se identificó la distribución mundial de las especies colombianas y su afinidad geográfica, y se encontró mayor afinidad con el Atlántico norte y las Antillas que con el Atlántico sur y el Golfo de México, asimismo, las subprovincias geográficas que incluyen a Colombia son zonas de transición dentro de la subprovincias septentrionales y australes del Gran Caribe.

Assuntos

RESUMO

Cyclopoida species from the Neotropics are listed and their distributions are commented. The results showed 148 species in the Neotropics, where 83 species were recorded in the northern region (above upon Equator) and 110 species in the southern region (below the Equator). Species richness and endemism are related more to the number of specialists than to environmental complexity. New researcher should be made on to the Copepod taxonomy and the and new skills utilized to solve the main questions on the true distributions and Cyclopoida diversity patterns in the Neotropics.

Foram listadas as espécies de Cyclopoida dos Neotrópicos e sua distribuição comentada. Os resultados mostram um número de 148 espécies, sendo que 83 espécies registradas na Região Norte (acima da linha do Equador) e 110 na Região Sul (abaixo da linha do Equador). A riqueza de espécies e o endemismo estiveram relacionados mais com o número de especialistas do que com a complexidade ambiental. Novos especialistas devem ser formados em taxonomia de Copepoda e utilizar novas ferramentas para resolver as questões sobre a real distribuição e os padrões de diversidade dos Copepoda Cyclopoida nos Neotrópicos.

Assuntos

RESUMO

Cyclopoida species from the Neotropics are listed and their distributions are commented. The results showed 148 species in the Neotropics, where 83 species were recorded in the northern region (above upon Equator) and 110 species in the southern region (below the Equator). Species richness and endemism are related more to the number of specialists than to environmental complexity. New researcher should be made on to the Copepod taxonomy and the and new skills utilized to solve the main questions on the true distributions and Cyclopoida diversity patterns in the Neotropics.

Foram listadas as espécies de Cyclopoida dos Neotrópicos e sua distribuição comentada. Os resultados mostram um número de 148 espécies, sendo que 83 espécies registradas na Região Norte (acima da linha do Equador) e 110 na Região Sul (abaixo da linha do Equador). A riqueza de espécies e o endemismo estiveram relacionados mais com o número de especialistas do que com a complexidade ambiental. Novos especialistas devem ser formados em taxonomia de Copepoda e utilizar novas ferramentas para resolver as questões sobre a real distribuição e os padrões de diversidade dos Copepoda Cyclopoida nos Neotrópicos.

RESUMO

Cyclopoida species from the Neotropics are listed and their distributions are commented. The results showed 148 species in the Neotropics, where 83 species were recorded in the northern region (above upon Equator) and 110 species in the southern region (below the Equator). Species richness and endemism are related more to the number of specialists than to environmental complexity. New researcher should be made on to the Copepod taxonomy and the and new skills utilized to solve the main questions on the true distributions and Cyclopoida diversity patterns in the Neotropics.

Foram listadas as espécies de Cyclopoida dos Neotrópicos e sua distribuição comentada. Os resultados mostram um número de 148 espécies, sendo que 83 espécies registradas na Região Norte (acima da linha do Equador) e 110 na Região Sul (abaixo da linha do Equador). A riqueza de espécies e o endemismo estiveram relacionados mais com o número de especialistas do que com a complexidade ambiental. Novos especialistas devem ser formados em taxonomia de Copepoda e utilizar novas ferramentas para resolver as questões sobre a real distribuição e os padrões de diversidade dos Copepoda Cyclopoida nos Neotrópicos.