The margaritona(Margaritifera auricularia) is included in the Red List of the International Union for Conservation of Nature (IUCN) in the “Critically Endangered” category. The Mediterranean naiad(Unio mancus) is included in the “near threatened” category and has a very limited range. Both are valuable bioindicators of the quality of the water in which they are found.
The aim of this project is to contribute to the recovery plan for Margaritifera auricularia by maintaining and studying the growth of juveniles from the Aragon area in order to analyze the problems of reproduction in captivity and potential future reintroduction experiences. In addition, habitat conservation actions for Unio mancus are included, promoting land stewardship for the species. Also, the environmental DNA detection technique has been used as a tool for monitoring naiad populations and the study of their distribution, profiling and validating its effectiveness during the development of the project.
Finally, understanding that the conservation of an endangered species is not possible if environmental education is not included as a basic tool for the execution of the project, volunteering actions and the publication of pedagogical material aimed at all educational levels have been included.
The general objective of the project has been to contribute to the conservation of the margaritona(Margaritifera auricularia) and the Mediterranean naiad(Unio mancus) and to prevent their decline in Spain.
The specific objectives were as follows:
“The River Goddesses” is a conservation project for the critically endangered IUCN Red List margarita(Margaritifera auricularis) and the Mediterranean naiad(Unio mancus), also threatened.
Regarding the first species, the project has contributed to increase the knowledge on the maintenance of juveniles born in the Aragon breeding center. As for the second species, the validity of new methodologies for captive breeding has been ratified, multiplying by 10 the success obtained in previous experiences. The populations of both species have also been monitored through the usual survey methods, but also through environmental DNA. Likewise, more than 25 kilometers of river have been studied and censused in the surveys carried out during these two years of the project to study population densities of Unio mancus.
On the other hand, 300 meters of riverbed have been restored and 4 populations have been recovered for Unio mancus (with 1,100 individuals in total), on six farms in which the entity maintains land stewardship agreements, which has demonstrated, according to the entity, the value of this tool for the conservation of naiad habitats . A channel was also repaired to prevent water losses and the riverbank vegetation, as well as the water storage capacity in some sections of the river, riverbank trees have been planted and a protective fence was installed in the same plantation. Another way to restore the habitat of these mollusks has been to control invasive crab populations, especially the signal crab(Pacifastacus leniusculus), capturing a total of 16,352 individuals in the sections with naiad populations.
Finally, several volunteer and environmental education activities have been carried out and educational materials on naiads have been developed and sent to schools in Catalonia and Aragon. In addition, a day of workshops on the conservation of ecosystems and endangered fauna was held, and a brochure was published in digital format to inform about land stewardship among landowners and entities for the management of habitats for naiads and other endangered species. Likewise, environmental volunteer days have been held with school students for the planting of riparian vegetation.
Contribution to the conservation of the naiads Margaritifera auricularia and Unio mancus (“The Goddesses of the River”).