Branchiopdelidae are a family of macroinvertebrates recently identified in the Ebro basin that live in the claws of another introduced species, the signal crab. PHOTO: department of Zoology and Ecology.

The researchers of the School of Sciences of the University of Navarra Javier Oscoz, David Galicia and Rafael Miranda, together with other Spanish experts and in partnership with the Hydrographic Confederation of the Ebro (CHE), have edited a document of reference letter for the identification of macroinvertebrates of the Ebro basin. It includes a total of 23 invasive species and the first guide of these animals published in Spain.

According to Javier Oscoz, many of them are tiny species, even parasites of other introduced animals. "Some of them are expanding, usually helped by man, consciously or unconsciously, such as the zebra mussel -perhaps the best known for the economic damage it causes by clogging irrigation canals- the Asian clam, American or Australian crabs, the apple snail, the Malaysian trumpet snail, etc.", he explains.

However, specialists consider that the state of conservation of the Ebro basin has improved considerably in recent years, thanks in part to the water quality control programs of study that has been carried out for decades. However, they recognize that there are still areas with a lower ecological quality, in the vicinity of large urban and industrial centers, where work is being done to minimize the impact as much as possible.

"The correct identification of these organisms," stresses Javier Oscoz, "is especially important because there are certain taxa or species that do not tolerate alterations in the environment or those caused by contamination. On the other hand, others are very resistant. Distinguishing between them allows us to detect changes in an ecosystem due to the presence of only resistant species, or to know the distribution of groups that may be threatened".

Two pioneering guides in Spain
The two manuals published allow the identification of aquatic macroinvertebrates in the basins of the Ebro, in the first case, and of the rest of the country's rivers, in the second. This group of animals includes invertebrates large enough to be seen without the need for magnification and that live, at some point in their life cycle, in the aquatic environment. "This includes a large number of species from different groups, such as annelids, mollusks or arthropods, many of them insects, which play a fundamental role in aquatic ecosystems, where they transform the organic subject and represent the main feeding source of higher organisms," explains Javier Oscoz.

The fact of identifying them in a guide with high quality photographs will facilitate the knowledge of an important part of our biodiversity,"which will help to develop a more efficient management of resources, as stated in the objectives of the Directive framework Water for 2015," concludes the researcher of the University of Navarra.