Nebria complanata, Groix island, France

[wollastoni]

I had the pleasure of observing Nebria complanata for the first time in my life on the island of Groix, Brittany, NW France.
This carnivorous species hides under pebbles on European and North African sandy beaches and feeds on sand hoppers.

nebria-complanata-groix.jpg (363.91 KiB) Viewed 1536 times

This species has almost completely disappeared from European coasts. One of the suspected reasons for this is the cleaning of beaches by tourists, who remove seaweed from the beaches.

However, the species has also disappeared from natural, non-tourist beaches, so this is not the only reason.

[wollastoni]

Some information about its current distribution in France and UK :

"Coastal urbanization, tourist pressure and, above all, the systematic cleaning of beaches appear to be the main threats to this species, with the exploitation and collection of floated wood, and the disappearance of tidal flats fragmenting its habitat (Courtial, 2013). In recent years, visitors to Les Glénanconstruct more and more cairns on the beaches (B. Ferré, pers. comm.). Several individuals have been found crushed between the stones of these constructions: combined with the disturbance caused when the stones are moved, these cairns could have an impact on the populations.

Once a very common species on the Atlantic and mid-ocean estrans, the great nebria now seems to have disappeared from the French mainland Atlantic coast. Until 1923, the species was present and very common all along the Aquitaine coast, and further north as far as Brittany, albeit in lesser abundance (Souverbie, 1855; Péneau, 1905; Baudrimont, 1923). The last data from the continental coast of Ille-et-Vilaine date from the early 20th century (Houlbert & Monnot, 1910), from the 1980s in Morbihan (Hervé, 1988), from the 1990s in Finistère and Vendée (Clémentelle, 1995; Herbrecht et al., 2017), and from 2000 along the Aquitaine coast (Thomas, 2011). The same negative population dynamics have been observed in the UK, with the last record for England in 2002, and the disappearance of numerous populations between the 1980s and the present day in Wales, which appears to be home to the last populations in Great Britain (Stewart, 2017).

The current status of mediterranean populations is unknown. In Brittany, the species was cited in Ille-et-Vilaine (Rothéneuf), Finistère (Audierne,Carantec, Glénan, Goulven, Plouescat,Roscoff, Santec, Tréflez, Trégunc) and Morbihan (Lorient, Quiberon, Riantec)(Houlbert & Monnot, 1910 ; Baudrimont,1923 ; Jeannel, 1941 ; Hervé, 1988 ;Clémentelle, 1995 ; Courtial , 2013 ;Herbrecht et al. , 2017 ; P. Devogel, comm.pers.). As early as 1981, Dachy (1984) reported that it had not been found in mainland Brittany, and that more southerly stations were also in decline or had even disappeared. Entomologists, notably those at Gretia (Groupe d'étude des inverté-brés armoricains), have observed that this gradual disappearance is continuing. Today, the species seems to be present in Brittany only on certain islands: Hoëdic, Groix and the Glénan archipelago (Courtial, 2013; Herbrecht et al., 2017).In addition to these few island populations, the great nebria has just been discovered in Noirmoutier, Vendée, in September 2018 by Didier Desmots and Nicolas Romet (F. Herbrecht, pers.comm.). This observation raises hopes of further discoveries on the islands of the French Atlantic coast, and even on the mainland."

translated from this great paper published in 2019 by Thibault Ramage, a French entomologist.

[Chuck]

Interesting, thanks for sharing that. I wonder how the species is faring in North Africa?