Line of action:

Terrestrial ecosystems

Status:

Finalizado

Execution date:

2019

Total budget:

€33,306.14

Amount of aid from the Biodiversity Foundation:

€28,290.24

The situation of Margaritifera auricularia in Spain, declared in a critical situation, has worsened in recent years. Margaritifera auricularia is one of the rarest and most endangered freshwater bivalve species in Europe. The decline of its populations in the last two centuries has been estimated at more than 90% and today it is almost extinct, with only one population in Spain (declared in a critical situation) and four in France. Since 2013, episodes of mass mortality have been observed in the Imperial Canal of Aragon, where more than 90% of the Spanish population is concentrated. During this period, more than 35% of the specimens have died and if this mortality rate is maintained, it is expected that the species will become completely extinct in Spain in the very short term. The characteristics of these mortalities, as with other species outside Spain, allow us to assume the existence of pathogenic organisms as causal agents. The main objective of this project is to test this hypothesis by determining the possible pathological causes that may be intervening in its mortality and thus establish the appropriate management measures that guide its effective management.

The main objective is to improve the knowledge of the mortality events that have affected the populations of M. auricularia, and to determine what are the ecological and biological characteristics of the episodes of mass mortality of M. auricularia produced in Spain prior to 2019.

It has the following specific goals:

• To improve the knowledge of mortality events that have affected M. auricularia populations, and to determine the ecological and biological characteristics of mass mortality episodes.
• To review the existing data on the presence of M. auricularia based on the documentation provided by the Government of Aragon and the scientific bibliography.
• Propose effective management measures for the conservation of the species.
• Halting the decline of M. auricularia and other naiads in Spain

• To obtain samples in a locality not affected by the mortalities in order to be able to compare them with samples from localities where they had been observed.
• To identify the potential etiological agents responsible for mass mortality events.
• To characterize the diversity of potentially pathogenic organisms (fungi, viruses and bacteria) present in freshwater bivalves affected and not affected by mass mortality events.
• Study the samples using “DNA metabarcoding” techniques to characterize the diversity of fungi and bacteria in the samples studied.
• To achieve a high degree of coordination, both internally among the project participants and externally with the rest of the competent authorities.
• To disseminate the results obtained and the appropriate management measures in the autonomous communities of Aragon, Navarre, La Rioja and Catalonia.

• It has been proven that the population of the Imperial Canal of Aragon is subject to different and serious impacts, such as maintenance works, extreme fluctuations in flow and water pollution, which have led it to an extreme conservation situation.
• Several agents have been detected, such as bacteria of the genus Flavobacterium, cyanobacteria of the genus Leptolyngbya, and several viruses, which could be the cause or contributors of the mortality of auricularia observed in Spain.
• The data collected could be useful to define the future conservation strategy of the species, in which it seeks to involve specialists and competent authorities in the field.
• The results obtained and the list of management measures identified have been sent to the competent authorities in the matter identified, both regional and state.