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One of the goals of the European network CRAYNET - entitled "European crayfish as keystone species-linking science, management and economics with sustainable environmental quality" - is to identify current crayfish protection programmes carried out in individual countries. During this roundtable held at the CRAYNET meeting in Innsbruck 2004, we tried to evaluate the projects that aimed directly at crayfish conservation or at habitat improvement in order to protect crayfish environments. Different approaches and new skills were discussed in order to increase understanding of the advances and positive results obtained on the management of native populations (species status, habitat, population, control of aliens, diseases etc.).

In the past, conservation programmes for a given species consisted in restoring the habitat and in translocating individuals without knowledge of their taxonomic status. Even if managers wanted to be informed, the “traditional taxonomy”, based on morphological characters, was discouraging because it could indicate several types of classification. This is the case for Austropotamobius pallipes, considered as a species complex. Today, conservation genetics aims to maintain, on one hand, the genetic specificity of populations (genetic integrity principle) and, on the other hand, the genetic diversity within and between populations (biodiversity principle), these basic principles being considered both at the level of protection measures and management measures. As an endangered species, A. pallipes is subjected to a loss of genetic diversity, a result of deterioration of water quality responsible for habitat fragmentation, with populations being confined to headwaters of the catchments. Consequently a certain degree of genetic variability must be maintained within the species because it governs the adaptation potential: the populations must be capable of responding to new environmental conditions. In A. pallipes, recent studies from several countries attempt to first describe the distribution of the present natural populations and secondly, by studying mitochondrial DNA, to clarify the taxonomy (number and identification of the present species and subspecies by phylogenetic inferences) and to assess the biogeographical history. These two preliminary steps are fundamental before defining conservation units and working at the catchment level, using highly polymorphic nuclear markers. The new approach has provided a good framework for research, with more frequent dialogues between geneticists and managers.

The phylogenetic relationships of the genus Austropotamobius were reviewed by the compilation of two recent genetic studies based on the partial nucleotide sequence of the mitochondrial RNA 16S gene. The results showed a well-resolved phylogeny revealing four distinct clades: A1, A2, A3 and B, supported by high bootstrap values. The clades A (including A1, A2, A3) and B are separated by a high genetic divergence (5%). In accordance with morphological and nuclear data, two species could be defined: A. italicus and A. pallipes, respectively. The average of genetic divergence within the major group A and B was 2.1% ± 1.2 and 0.9% ± 0.6 respectively. Three clades A1, A2 and A3 correspond mainly to crayfish sampled from Austria-Switzerland, South of Balkans and Italy-Spain respectively. On the basis of morphological, genetic and distribution data, a new systematic - based on two species A. pallipes and A. italicus with 3 subspecies A. i. carinthiacus, A. i. carsicus and A. i. italicus - could be proposed for the white-clawed crayfish species complex. We rejected the specific status of A. berndhauseri and A. i. lusitanicus given to the Swiss and Spanish crayfish respectively.

L'ecrevisse a pattes blanches Austropotamobius pallipes pallipes a encore une large repartition en France mais, depuis le siecle dernier, les populations ont ete serieusement reduites a cause de la degradation des habitats suite a l'activite humaine et ont egalement ete decimees par la peste de l'ecrevisse, suite aux introductions d'especes d'ecrevisses exotiques. Si des actions de conservation d'A. pallipes sont urgentes a mettre en place, elles ne peuvent se faire sans une estimation prealable de la variabilite genetique des populations chez cette espece actuellement en voie de disparition. La variabilite de l'ADN mitochondrial (ADNmt) dans les populations naturelles est examinee par polymorphisme de la longueur des fragments de restriction a partir d'echantillons issus de quinze populations francaises et de six populations europeennes representatives de la repartition des trois sous-especes observees chez Austropotamobius pallipes, ceci afin d'examiner l'etendue de la variabilite genetique au sein de l'espece. Des considerations biogeographiques sont faites a partir des distances genetiques obtenues entre les trois sous-especes. L'etude revele un faible niveau de variabilite genetique au sein des populations anglaises, galloises et la plupart des populations francaises, ce qui correspond a une certaine homogeneite genetique du stock parmi les populations d'A. pallipes pallipes. En effet, les deux seules populations francaises presentant un haut niveau de variabilite genetique sont en fait des populations mixtes. La comparaison avec les resultats obtenus chez les populations europeennes montre que l'une est composee des deux sous-especes A. pallipes pallipes et A. pallipes italicus et la deuxieme d'A. pallipes italicus et A. pallipes lusitanicus. Les resultats prouvent que quelques tentatives de repeuplement, faites dans le passe a partir d'individus d'A. pallipes italicus et supposees avoir echoue, peuvent avoir reussi et que le stock astacicole francais ne doit pas correspondre a la seule sous-espece A. pallipes pallipes. Une premiere analyse realisee au niveau regional montre qu'il n'existe pas de structuration genetique entre les bassins hydrographiques, ce qui pourrait traduire l'intervention de l'homme pour des transferts de populations entre bassins. En consequence, l'ADNmt est un bon marqueur pour mesurer la variabilite genetique au sein des populations d'ecrevisses, pour cartographier precisement comment les trois sous-especes sont reparties en France et quelle est l'importance de chacune avant d'entreprendre toute operation de repeuplement de l'ecrevisse autochtone.

Mitochondrial DNA (mtDNA) variation in the white-clawed crayfish, Austropotamobius pallipes pallipes, was examined by restriction endonuclease analysis of samples obtained from three geographical locations representing two very différent habitats : the Crochatiere and the Magot for brooks and the Pinail for ponds. This study used a new type of molecular marker in crayfish. The method of mtDNA extraction was not based on the clear lysate method or on ultracentrifugation and used no end-labelling détection. It is discussed according to the literature about marine crustaceans. MtDNA was digested with 6 endonucleases. The molécule size of the mtDNA of the white-clawed crayfish was approximately 17750 ± 580 base pairs. Two restriction enzymes produced polymorphic digestion patterns, defining a total of three haplotypes (1-3). There was a shared haplotype 2 between individuals among the two brooks. The haplotype 3 was only found in individuals obtained from ponds of Pinail.