Mar. 20, 2009 The prevailing belief to date has been that the streams of south eastern Spain contained nothing of interest. However, a research project by the University of Murcia has shown that these ecosystems, which are unique in Europe, are home to great plant and animal biodiversity. This has enabled the research team to explode the myth that arid systems do not contain any organisms of interest, and to call for them to be protected because of their ecological value.
In general, semi-arid streams have low flow volume and little vegetation, and can seem to have minimal ecological value or interest. However, the reality is very different. Spanish scientists who have studied how they function at a global scale have found them to contain a greater number of species than those in wetter areas.
"We encountered a very high level of biodiversity, much higher than what we expected at the outset, and we realised that these systems function as refuges for biodiversity. In fact they contain a large variety of environments at micro-environment level", Marina Aboal, lead author of the study and a researcher at the University of Murcia, tells SINC.
The study is focused on the study of algal communities, and particularly of diatomeae (a class of microscopic, unicellular algae), since these organisms form the foundations of the entire ecosystem.
The biologists discovered more than 200 species of micro algae (which cannot be seen with the naked eye), some of which may be new to Science.
This finding is important because of the exceptional nature of this habitat in Europe. The south east of Spain, one of the most arid regions on the continent, is one of the few areas in Europe where semi-arid streams can commonly be found. These shelter "an extremely significant number of species, many of which are characteristic of these environments", says Aboal.
A unique ecological richness
The research team believes that these species of algae "deserve to be studied and included within conservation strategies", since they can adapt themselves to extreme conditions such as very high temperatures and high levels of evaporation and water salinity.
Failure to protect these ecosystems, which has been the situation to date, will mean "species will become extinct before we can even find and study them, or find out if they have any uses for us", says the botanist.
The experts stress that, since these are "humble and little known" ecosystems, information about the species that inhabit them is being lost. "The loss of species completely changes the way in which the river functions, and can cause chain reactions that lead to mini ecological catastrophe, with the loss of an ecosystem," warns Aboal.
Aside from being of ecological interest as the first link in the trophic chain, micro algae could also have "interesting" biotechnological applications. The expert says that if these are not protected and studied "we will never know whether they are useful". This is the great drama of extinction, with species disappearing before they can even be discovered.
The functioning of the entire system rests upon algae. These photosynthesising organisms are the primary producers, and form the foodstuff underpinning the entire ecological system in aquatic ecosystems. From an environmental point of view, they help to control the environmental quality of aquatic systems, and are essential for assessing their ecological status, or health.
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- Ros et al. Biodiversity of diatom assemblages in a Mediterranean semiarid stream: implications for conservation. Marine and Freshwater Research, 2009; 60 (1): 14 DOI: 10.1071/MF07231
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