Todos los Océanos tienen Plásticos en su Superficie

La Expedición Malaspina, a cargo del Consejo Superior de Investigaciones Científicas (CSIC), ha encontrado cinco grandes acumulaciones de residuos plásticos en el mar abierto, que coinciden con los cinco grandes giros de circulación de agua superficial oceánica.
Restos de plásticos en una playa (Una triste imagen)
Aparte de la ya tristemente célebre acumulación de basura plástica del Pacífico Nortehay extensiones similares de este tipo de basura en el centro del Atlántico Norte, el Pacífico Sur, el Atlántico Sur y el Océano Indico. Sin embargo, según un estudio de esta Expedición, las aguas superficiales podrían no ser el destino final de los residuos plásticos ya que grandes cantidades de microplásticos parecen estar pasando a la cadena alimenticia marina y a los fondos oceánicos. (Ir a Granada: Fallece un Cachalote ahogado en Plástico).

Los resultados del trabajo han sido publicados en la revista Proceedings of the National Academy of Sciences (PNAS). “Las corrientes oceánicas transportan los objetos plásticos, que se resquebrajan en fragmentos cada vez más pequeños debido a la radiación solar. Esos pequeños trozos conocidos como microplásticos que fueron detectados en el 88% de la superficie oceánica muestreada durante la Expedición Malaspina 2010 pueden llegar a durar cientos de años, explica el investigador Andrés Cózar, de la Universidad de Cádiz, que ha liderado la investigación.
Fuente: Muy Interesante

Fish-eating Spiders discovered Worldwide

Spiders are traditionally viewed as predators of insects. Zoologists from Switzerland and Australia have now published a study that shows: spiders all over the world also prey on fish.

Fishing spider Dolomedes facetus captured fish (genus Xiphophorus) in garden pond near Brisbane, Queensland, Australia.
Credit: Peter Liley, Moffat Beach, Queensland, CCBY
Spiders are traditionally viewed as predators of insects. Zoologists from Switzerland and Australia have now published a study that shows: spiders all over the world also prey on fish. The academic journal PLOS ONE has just published the results.

Although viewed by ecologists as the classical predators of insects, researchers have become increasingly aware that spiders are not exclusively insectivorous. Certain larger-sized species supplement their diet by occasionally catching small fish. This shows a new study by zoologist and spider expert, Martin Nyffeler from the University of Basel, Switzerland and Bradley Pusey from the University of Western Australia. The researchers gathered and documented numerous incidents of spiders predating fish from all around the world.


Fish as a diet supplement
According to their systematic review, spiders from as many as five (5) families have been observed predating on small fish in the wild and three (3) more families contain species that catch fish under laboratory conditions. These so called semi-aquatic spiders typically dwell at the fringes of shallow freshwater streams, ponds or swamps. These spiders, some of which are capable of swimming, diving and walking on the water surface, have powerful neurotoxins and enzymes that enable them to kill and digest fish that often exceed them in size and weight. "The finding of such a large diversity of spiders engaging in fish predation is novel. Our evidence suggests that fish might be an occasional prey item of substantial nutritional importance," says Martin Nyffeler.


Based on this study, naturally occurring fish predation by spiders has been reported from all continents with the exception of Antarctica. Most incidents have been documented in North America, especially in the wetlands of Florida, where semi-aquatic spiders have often been witnessed catching and eating small freshwater fish such as mosquitofish. In order to catch its prey, the spider will typically anchor its hind legs to a stone or a plant, with its front legs resting on the surface of the water, ready to ambush. The fish will then be dragged to a dry place before the feeding process can begin which usually lasts several hours.
Source: Science Daily

90 Percent of Lemur Species Face Extinction (90% de los Lemures en Peligro de Extinción)

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(Spanish & English article)

English article
Slipper orchids (subfamily Cypripedioideae) are another group with many species in peril.

An orchid of the genus Paphiopedilum
Entire branches of the tree of life are in danger of being wiped out: The majority of species in some groups of plants and animals are now on the "Red List" of the world's most threatened species.

The list, which is managed by the International Union for Conservation of Nature (IUCN) and was updated this week, shows that among the groups most at risk are lemurs and temperate slipper orchids.
Found only in Madagascar, 90 of the 101 species of lemur are threatened with extinction, the IUCN said. More than 20 percent of these small primates are listed as being critically endangered, meaning that they have a very high risk of extinction in the wild. The main threat stems from illegal logging of tropical forests, which has accelerated in the island nation in recent years.
Coquerel's Sifaka Lemur (www.newsobserver.com)
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Las orquideas Zapatillas de Venus o Zapatillas de Dama (subfamilia Cypripedioideae) son otro grupo con muchas especies en peligro.
Ramas enteras del árbol de la vida están en peligro de desaparecer: La mayoría de las especies en algunos grupos de plantas y animales están actualmente en la "Lista Roja" de las especies más amenazadas del mundo. 
Esta lista, que es administrada por la Unión Internacional para la Conservación de la Naturaleza (UICN) y que se actualizó esta semana, muestra que entre los grupos de mayor riesgo están los lemures y las orquídeas zapatilla de climas templados. 
Según la UICN, 90 de las 101 especies de lemures localizadas exclusivamente en Madagascar, están en peligro de extinción. Más del 20 por ciento de estos pequeños primates están listados como en peligro crítico, lo que significa que tienen un riesgo muy alto de extinción en estado silvestre. La principal amenaza proviene de la tala ilegal de los bosques tropicales, que se ha acelerado en dicha isla en los últimos años.

Lemur Pigmeo (Microcebus myoxinus)

Lorenzo, El Francés Volador (Lorenzo, the Flying Frenchman)

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(Spanish & english article)

Articulo en Español
En la Camarga, en la costa sur de Francia, un hombre vive con sus caballos. Una asociación única, que ha logrado solo a través de sus instintos. Una relación de completo entendimiento. Las actuaciones que realiza aquí con sus caballos son únicas en el mundo.
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English article
In Camargue, in the south of france, a man lives with his hourses. A unique experience of partnership, obtaining by his instint alone. A relationship of complete understanding. The exploits he acomplished here, are a performance unique in the world.

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Factors affecting the Coexistence of specialist and generalist Species

The coexistence of specialists and generalists in metacommunity is mediated by species traits and environmental factors

Differences between specialist and generalist species

Generalists such as raccoons are sometimes able to adapt to urban environments.

Animal species reside on a scale with “generalist” on one end and “specialist” on the other. Specialists can live only in a narrow range of conditions: diet, climate, camouflage, etc. Generalists are able to survive a wide variety of conditions and changes in the environment: food, climate, predators, etc.

Specialists thrive when conditions are just right. They fulfill a niche and are very effective at competing with other organisms. They have good mechanisms for coping with “known” risks. But when the specific conditions change, they are much more likely to go extinct. Generalists respond much better to changes/uncertainty.


A specialist animal, the koala only lives in and eats the leaves of eucalyptus trees.



Specialization puts species at extreme risk


Human activities and environmental changes are driving many species to extinction. Species that exhibit a narrow environmental tolerance (specialist species) are particularly vulnerable and are currently declining worldwide. Their extinction strongly modifies the species composition of ecosystems. We can therefore observe the thriving of species with wide environmental tolerance (generalist species). For the maintenance of biodiversity and for the design of adapted management strategies it is crucial to understand which factors drive the maintenance of specialist species in ecosystems.


L. Büchi and S. Vuilleumier of the University of Lausanne in Switzerland have analyzed a model to identify the factors impacting the coexistence of specialist and generalist species. Two key factors have a drastic influence on the species composition of communities: species’ dispersal ability and the number of interacting species. Low dispersal limits the spread of specialist species, as their narrow environmental tolerance creates barriers that prevent them from reaching other favorable habitats. In contrast, it favors generalist species which are able to disperse gradually to neighboring habitats thanks to their higher environmental tolerance. When the number of interacting species is large, more specialist species are found as they have a strong advantage over generalist species in their habitats. Ecosystem loss and fragmentation might then drive specialist species to extinction as these factors limit species dispersal and reduce the number of species in ecosystems.


This work elucidates how species with different environmental tolerances can coexist together. In addition, it provides new insights into the design of conservation and management strategies. In particular, the future survival of specialist species relies on the conservation of whole ecosystems and the maintenance of high connectivity between them.