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The silent extinction of freshwater mussels in Portugal.

Authors :
Lopes-Lima, Manuel
Reis, Joaquim
Alvarez, Maria G.
Anastácio, Pedro M.
Banha, Filipe
Beja, Pedro
Castro, Paulo
Gama, Mafalda
Gil, Maria G.
Gomes-dos-Santos, André
Miranda, Fernando
Nogueira, Joana Garrido
Sousa, Ronaldo
Teixeira, Amílcar
Varandas, Simone
Froufe, Elsa
Source :
Biological Conservation. Sep2023, Vol. 285, pN.PAG-N.PAG. 1p.
Publication Year :
2023

Abstract

Freshwater mussels are one of the most threatened animal groups in the world. In the European Union, threatened and protected mussel species are not adequately monitored, while species considered to be common and widespread receive even less attention. This is particularly worrying in the Mediterranean region, where species endemism is high and freshwater habitats are severely affected by water scarcity. In the absence of hard data on population trends, we report here a long-term comparison of freshwater mussel assemblages at 132 sites covering 15 different hydrological basins in Portugal. This study reveals a widespread decline of 60 % in the number of sites and 67 % in the overall abundance of freshwater mussels across Portugal over the last 20 years, indicating that all species are rapidly declining and threatened with extinction. These results show that current legislation and conservation measures are largely ineffective and highlight the importance of updating the Habitats Directive to enforce standard monitoring protocols for threatened species in the European Union and to extend monitoring to other freshwater species thought to be common and widespread. Efficient water management, restrictions on irrigation expansion in important biodiversity areas, mitigation of hydrological changes and loss of aquatic habitat connectivity caused by physical alterations are urgently needed to reverse these declining population trends. For the severely endangered species Margaritifera margaritifera , Potomida littoralis , and Unio tumidiformis , where populations are now critically low, more urgent action is needed, such as ex-situ conservation, protection of remaining populations and large-scale habitat restoration. • Protected freshwater mussels are ineffectively monitored in the European Union. • Common freshwater mussel species are generally not monitored. • Long-term survey reports a massive decline of freshwater mussel species in Portugal. • Water depletion, dams and invasive species are the main causes of decline. • Improved water and catchment management urgently needed. • Changes to the Habitats Directive proposed. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00063207
Volume :
285
Database :
Academic Search Index
Journal :
Biological Conservation
Publication Type :
Academic Journal
Accession number :
171829655
Full Text :
https://doi.org/10.1016/j.biocon.2023.110244