Biology


ZEBRA MUSSEL

The zebra mussel is a species of small freshwater mussel, an aquatic bivalve mollusc. This species was originally from the regions of the  Black, Aral and Caspian seas but it has been accidentally introduced in many other areas as the Ebro River, and has become and invasive specie.

The zebra mussel has a triangular shape and in their shell it has dark grey and black stripes. It could be 5cm long but usually it is 3cm, and it could live 5 years. They live grabbed in the soil thanks to some “strings” (byssal threads) so it is very difficult to remove them. They grab in the rocks of the rivers, in pipes (collapsing them, so they have to be changed more frequently and more money is spent), boats and on the shells of other animals, not allowing them breath and eat, so they die. The zebra mussels filter the water so as it has less particles more light pass trough it, making plats grow and, as they need oxygen, less oxygen can be taken from fish so they also die.

The zebra mussel is an alloctone species in Aragon and it is changing the plants and animals of these rivers, and also the relationships between the humans and the nature because we have taken it here, and because it will be our job to take it out.

The cycle of cebra mussel's life

This is the cycle of the life of the zebra mussel

The characteristical stripes of the shell of the zebra mussles.

How the zebra mussels grab anywhere they can.

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The Pyrenean newt is a kind of salamander found in the Pyrenees of Andorra, France and Spain. Its natural habitats are temperate forests, rivers, freshwater lakes, marshes and caves.

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In the image, the “Ibón de las Ranas”, a tarn located in the Pyrenees, which is home of a community of newts, among other species.
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Adults are 10 to 15 cm long of which almost half is the tail. Their back is of an uniform dark brown colour, sometimes with yellow spots or a yellow longitudinal stripe. They have also a yellowish or orange belly. Unlike other species of non- Pyrenean newts, the adult has no crest on the back or tail. The larvae are lighter in colour, with dark spots, but they do have a crest on the tail.
The Pyrenean newt diet is compound of a wide range of insects and other aquatic invertebrates. They have an hibernation period of 8-9 months, depending on the altitude, which varies between 500 and 2500 m.

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It is an oviparous amphibian. In mating season, males belly turns orange, while females maintain their grey colour with a yellowish stripe on the middle. They reproduce by internal fecundation. The copulation happens in the water and takes several hours. The metamorphosis between larvae and adults lasts for one year. However, at high altitudes these time almost doubles.
This specie , although it is not endangered, has been rated as Nearly in Damage. Their main threat is habitat destruction, the process in which a natural ecosystem becomes unable to support the species present in it. Also, they are very vulnerable at the day because they remain still on the ground, making an easy target for predators and even for humans.
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The images are from this website.
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According to the UN’s figures of 2007, in Spain a 36 % of the territory is suffering desertification at different states. This means that over a third of the land is gradually becoming unproductive and infertile. This phenomenon specially affects the Mediterranean watershed and the Canary Islands, though the issue is spreading in most part of the state. This fact positions Spain as the European country with the higher risk of desertification.

Map of risk of desertification in Spain

What has triggered this problem is the damaging of soil which can be due to natural processes such as erosion or changes in the vegetative cover. Even though, the truth is that the human impact is the major cause and if not, it usually enhance the intensity of the others. Agricultural activities,fires, aquifer deplantation (taking water from subterranean springs) and urbanisation – among others – increase the stress the ground undergoes and therefore fasten the desertification. The unusual high percentage of Spain might be due to the dryness of the place as droughts are usual and deforestation (especially due to arson or accidental fires) is a growing problem.

By now at least a 6% of the affected land is irreversibly damaged and the percentage of threaten areas increases constantly (in 2008, already a 38% of soil was affected). This hazard entails other dangers as the environment is lost, the lifestyle of local populations is altered and may lead to their extinction and so, to the decrease of biodiversity.

Desertification in Aragón:

In Aragón the chances of desertification are quite similar to the Spanish average; around a third is in danger. Even though, we must remember this figure is still very high meaning that over 750 thousand hectares are in high risk of desertification.

We must add to this the fact that most of the territory, a 91,2%, has negative hydrologic levels – the soil losses more water than it absorbs -. As well, the territory is formed mainly by semiarid areas, which are especially sensible to desertification and droughts are usual. This is why Miguel Ángel Ena head of the Forestal Management and Planification department of the DGA (Aragonese county council) stated ‘Como se ve, en Aragón se dan la mayoría de las condiciones que favorecen la desertificación (As we can see, most conditions which favour desertification can be found in Aragón). Even though, despite showing most climatologic and geographical features leading to desertification, places with similar conditions such as Murcia or Valencia have over 90 % of its soil in risk. This remarkable difference between the percentages is thought to be due to the human abuse of natural resources, which in Aragon seems to be, fortunately, milder.

Nevertheless, prevention for avoiding ending in the same way is necessary. That’s why the Spanish government launched PAND (National Action Plan against Deforestation). The aims of it are to reduce the possibilities of deforestation happening and to enhance sustainable agriculture and the recovery of vegetable cover. In Aragon, this meant starting to plant over 5 million trees in 2008 as well as a detailed study for having a proper view of the problem. This project let us know that the most affected province in Aragón is Teruel with 21,31% of land in danger, being the first step towards getting people involved and aware of the lost of biodiversity.

Sources:

¤ Last three are in Spanish.

 

As I don´t  found information about bears in english , I have my information in spanish. Here is the information I had sumarised:

“A principios de este siglo, sólo quedaban dos núcleos: uno occidental y otro oriental. A nivel pirenaico, puede hablarse actualmente de tres núcleos. En lo que se refiere a la vertiente española, el núcleo occidental se ha ido reduciendo paulatinamente. El núcleo central cuenta hoy en día con una presencia esporádica. El núcleo oriental quedaría en territorio francés en su totalidad. Estos tres núcleos pirenaicos estaban interrelacionados, pues existía una presencia esporádica de osos entre ellos hasta los años sesenta. Todas las observaciones directas de huellas, indicios y daños al ganado de 1979 a 1991 se localizaron sobre un mapa dividido en unidades de aproximadamente 1.000 hectáreas, definidas por límites orográficos. Se pueden distinguir las siguientes zona Echo, Aragüés y el valle del Roncal de Navarra. El límite occidental queda definido por el valle de Salazar y el oriental por el valle de Aisa.

En 1954 evaluaba la población osera pirenaica en unos 70 osos.

En 1970, se hablaba de unos 30 osos en el Pirineo francés. En 1983, cuando ya se contaba con un mismo método de evaluación a ambos lados del Pirineo,contábamos con un mínimo de 13 osos en el Pirineo occidental y 6 en el Pirineo central. En 1991 ya sólo quedaban 11 osos en el Pirineo occidental y 1 ó 2 en el Pirineo central. Entre 1983 y 1991 han desaparecido prácticamente el núcleo oriental y central. . La última reproducción conocida es de 1980.

Entre 1977 y 1979 se produjeron activos desplazamientos desde los bosques de Ste. Engrace, Lanne, Arette hacia Roncal, Ansó y Echo y la parte suroeste del Valle de Aspe.

En el Pirineo occidental español entre 1983 y 1991 sólo se detectan huellas de desplazamientos, acompañados de gran número de ataques al ganado que supusieron la muerte segura de al menos 2 osos (tal vez 3).

La ganadería, el turismo y la explotación forestal son las tres actividades económicas fundamentales de la zona.”

I took the information from a govermet web page : http://www.mma.es/secciones/biodiversidad/especies_amenazadas/vertebrados/mamiferos/pdf/CAP16_OSOPARDO.pdf.

The Lammergeier or Bearded VultureGypaetus barbatus (“Bearded Vulture-Eagle”), is an old world vulture – not related to nowadays most common vultures. Its the only member of the genus Gypaetus. It breeds on crags in high mountains in southern Europe, Africa, India, and Tibet, laying one or two eggs in mid-winter which hatch at the beginning of spring. The population is resident. The Lammergeier has been successfully re-introduced into the Alps, but is still one of the rarest raptors in Europe.

Like other vultures, it is a scavenger, feeding mostly from carcasses of dead animals. It usually disdains the rotting meat, however, and lives on a diet that is 90% bone marrow. It will drop large bone from a height to crack them into smaller pieces. Its old name of Ossifrage (“bone breaker”) relates to this habit. Live tortoises are also dropped in similar fashion to crack them open.

The Bearded vulture reaches 1.10 m in size (from head to tail), its wingspan is around 2.8 m and it weighs about 5-7 kg.

Where to find the Gypaetus Barbatus Barbatus in Europe.

It’s also found in other places of Europe. Nowadays there are about 77 pairs in the Pyrenees, in the island of Corsica there are 10 pairs and in the Balkans there are 2-3 pairs, while in the Alps, where the species has been reintroduced, there are 80 individuals and 4 pairs.
Other exemplars can be found in the isle of Crete (Greece).

The bearded vulture is, however, not in a serious risk of extinguishing. More exemplars can be found in large zones of Africa and Asia, divided into two sub-species: the Gypaetus Barbatus Barbatus and the Gypaetus Barbatus Meridionalis. The ones in Europe are Gypaetus B. Barbatus.

A little video, filmed in the Spanish Pyrenees.

http://www.youtube.com/watch?v=SRAiprmegXg

Last but not least, a webpage from Spain dedicated to help this noble animal

http://www.quebrantahuesos.org/htm/es/fcq/intro.htm

Cheers 😀

Hi there,  this is a video about wels catfish hunting pigeons at Ebro river. I know the quality isn’t very good, but this is a clear example of how this fish hunt the birds.

For more information click here (source: wikipedia)

Here I post a link with a webpage about ecology which gives a good help with the topic.

I also recommend this search engine named Ecosia . For more information, watch this video about the webpage.

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