White-clawed crayfish Austropotamobius italicus (Faxon 1984) is a keystone species for freshwater environments. The A. pallipes species complex, which includes A. italicus, is listed as Endangered by the IUCN, having declined by 50-80% over the last decades due to competition with alien crayfish, pathogens, habitat degradation and overharvesting. Our goal was to carry out a fine-scale distribution and genetic survey in remote areas of wilderness, aiming to gain useful information and to offer management recommendations for the long-term protection of the species. In spring-summer 2015-2016 we investigated 8 mountain or hilly streams of the upper part of River Magra Basin, in the Lunigiana region (Tuscany). Despite the occurrence of some SCIs, data on the torrential fauna of Lunigiana are still scarce, with many streams having never been investigated and yet threatened by the planned construction of mini-hydroelectric plants. For each stream, we defined a 500 m-long transect; we carried out 51 surveys in total, both diurnal and nocturnal, to record crayfish occurrence, take morphometric measurements (cephalothorax and rostrum length), collect non-lethal samples for genetic analysis (one pereiopod per specimen) and check for ectosymbionts. Crayfish were found in two streams (Civasola and Verdesina), both located within the municipality of Pontremoli. Morphometric and genetic analysis (COI mtDNA gene: 36 specimens; microsatellite DNA genotyping at six loci: 60 specimens) indicated that both population belonged to the taxon A. italicus carinthiacus. DNA crayfish diversity was very low within each stream, whereas the two populations proved to be significantly differentiated from each other. Ectosymbionts were genetically identified (COI mtDNA gene: 10 specimens) as Branchiobdella italica Canegallo 1929 (Annelida, Clitellata). Civasola individuals (both genders) not only were larger than those found in the Verdesina stream but also not infested by branchiobdellids. We hypothesized that these two factors might be related to each other, with branchiobdellids being able to shift to parasitic habits and limit host growth when found at high density. In the light of the long-lasting occurrence of A. italicus in the study area and of remote location, altitude and other habitat features of both streams, we suggest that Civasola and Verdesina streams could be considered as “natural Ark sites” for the species, thus deserving further studies and ad hoc conservation actions. In the light of the long-lasting occurrence of A. italicus in the study area and of remote location, altitude and other habitat features of both streams, we suggest that Civasola and Verdesina streams could be considered as “natural Ark sites” for the species, thus deserving further studies and ad hoc conservation actions
Preliminary distribution and genetic data of Autropotamobius italicus (Faxon, 1914) in Lunigiana (Tuscany)
GUERRINI, MONICA;BARBANERA, FILIPPO;PETRONI, GIULIO
2017-01-01
Abstract
White-clawed crayfish Austropotamobius italicus (Faxon 1984) is a keystone species for freshwater environments. The A. pallipes species complex, which includes A. italicus, is listed as Endangered by the IUCN, having declined by 50-80% over the last decades due to competition with alien crayfish, pathogens, habitat degradation and overharvesting. Our goal was to carry out a fine-scale distribution and genetic survey in remote areas of wilderness, aiming to gain useful information and to offer management recommendations for the long-term protection of the species. In spring-summer 2015-2016 we investigated 8 mountain or hilly streams of the upper part of River Magra Basin, in the Lunigiana region (Tuscany). Despite the occurrence of some SCIs, data on the torrential fauna of Lunigiana are still scarce, with many streams having never been investigated and yet threatened by the planned construction of mini-hydroelectric plants. For each stream, we defined a 500 m-long transect; we carried out 51 surveys in total, both diurnal and nocturnal, to record crayfish occurrence, take morphometric measurements (cephalothorax and rostrum length), collect non-lethal samples for genetic analysis (one pereiopod per specimen) and check for ectosymbionts. Crayfish were found in two streams (Civasola and Verdesina), both located within the municipality of Pontremoli. Morphometric and genetic analysis (COI mtDNA gene: 36 specimens; microsatellite DNA genotyping at six loci: 60 specimens) indicated that both population belonged to the taxon A. italicus carinthiacus. DNA crayfish diversity was very low within each stream, whereas the two populations proved to be significantly differentiated from each other. Ectosymbionts were genetically identified (COI mtDNA gene: 10 specimens) as Branchiobdella italica Canegallo 1929 (Annelida, Clitellata). Civasola individuals (both genders) not only were larger than those found in the Verdesina stream but also not infested by branchiobdellids. We hypothesized that these two factors might be related to each other, with branchiobdellids being able to shift to parasitic habits and limit host growth when found at high density. In the light of the long-lasting occurrence of A. italicus in the study area and of remote location, altitude and other habitat features of both streams, we suggest that Civasola and Verdesina streams could be considered as “natural Ark sites” for the species, thus deserving further studies and ad hoc conservation actions. In the light of the long-lasting occurrence of A. italicus in the study area and of remote location, altitude and other habitat features of both streams, we suggest that Civasola and Verdesina streams could be considered as “natural Ark sites” for the species, thus deserving further studies and ad hoc conservation actionsI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
