Search

The giant freshwater pearl mussel Margaritifera auricularia (GFPM) is one of the most endangered bivalve species in the world. Originally occurring in many European rivers, the GFPM is a relict now restricted to a few ageing populations in France and Spain in which natural reproduction is almost absent.Like most unionoid mussels, the GFPM needs host fish for the development of their parasitic larvae (glochidia). The European sturgeon (Acipenser sturio), the only known native host fish of the GFPM in France, is essentially extinct. Therefore, the aim of this study was to identify other hosts that could be responsible for the few cases of recent recruitment.Natural infestation of wild fishes in three French rivers was assessed to identify potential hosts of M. auricularia, while artificial infestation experiments were conducted on the sea lamprey (Petromyzon marinus) and the wels catfish (Silurus glanis) to determine their compatibility as hosts.Among the 29 fish species assessed for natural infestation, only the three‐spined stickleback (Gasterosteus aculeatus) and the European eel (Anguilla anguilla) carried M. auricularia glochidia. In the artificial infestation experiments, living juvenile mussels were collected from both P. marinus and S. glanis. The number of juveniles collected from a single P. marinus specimen (13,827) suggests that this species is a highly efficient host. As with previously known hosts, newly identified ones also appear to have a relationship with marine environments.The present findings suggest that P. marinus has played a key role in preventing the total extinction of M. auricularia in France, and indicate the potential use of P. marinus in conservation strategies aimed at reintroducing or stabilizing populations of this rare mollusc. [ABSTRACT FROM AUTHOR]

The State of Mato Grosso in Brazil has undergone intensive land use changes over the past decades. Native ecosystems have been converted into agrosystems for the production of cash crops and cattle. The Brazilian Forest Code advocates full protection of specifically sensitive habitats, and it also safeguards a fixed percentage of native vegetation known as 'Legal Reserves' (LRs) inside private rural properties. As part of Brazilian Legal Amazonia region, in Mato Grosso, these percentages account for 35 % of savannas and 80 % of forests found inside each rural property. Here we analyze at the scale of the three biomes: Cerrado, Amazonia and Pantanal, the changes in native vegetation cover (NVC) from 1992 to 2007 and the representativeness of NVC types within the LRs, as well as the role of LRs for general landscape configuration and conservation. In Mato Grosso, 90 % of all studied NVC types are represented inside LR patches. Legal Reserves also accounted for 37 % of the total protected areas and for 37.8 % of all remnant NVCs found in Mato Grosso in 2007. The importance of LRs for landscape structure varied greatly according to biome, but it is noteworthy that LRs were generally missing in highly deforested zones. The relative small size of LRs in all biomes (55 to 64 % of them are ≤12 ha) makes them specifically vulnerable to further changes in land use. Considering the current tendency of ongoing fragmentation, the importance of LRs for landscape connectivity should be increased, specifically by improving the network of corridors between these remnant native vegetation areas. [ABSTRACT FROM AUTHOR]