title: Effects of small weirs on fish parasite communities.
abstract: In this study, we examined the impacts of small weirs on the parasite community of gudgeon and toxostome in a medium-sized river. We tested changes on parasite species diversity using indices that capture both richness and abundance characteristics, and we examined parasite community structure with null models (co-occurrence index C score) and a multiple discriminant function analysis (MDFA). Our results showed that parasite community diversity of gudgeon is strongly influenced by weirs with a maximum diversity upstream of the weirs. Weirs also induce change in abundance of gudgeon parasite species particularly during summer. Nevertheless, we obtained that weirs had no effect on the parasite co-occurrence patterns. In addition, similarity indices indicate that the parasite faunas of newly established limnophilic species (roach and bleak) are host-specific and are rarely transmitted to other fish species. We conclude that fish parasite communities responded in different ways to the presence of impassable weirs, but, in a general tendency, changing environmental conditions induced by weirs may represent an ecological risk.
authors.affiliation: Laboratoire Evolution et Diversité Biologique, U.M.R. 5174, CNRS-Université Paul Sabatier, 118 route de Narbonne, 31062, Toulouse Cedex 4, France. loot@cict.fr
authors.forename: Geraldine
authors.initials: G
authors.lastname: Loot
authors.forename: Yorick
authors.initials: Y
authors.lastname: Reyjol
authors.forename: Nicolas
authors.initials: N
authors.lastname: Poulet
authors.forename: Andrea
authors.initials: A
authors.lastname: Simkova
authors.forename: Simon
authors.initials: S
authors.lastname: Blanchet
authors.forename: Sovan
authors.initials: S
authors.lastname: Lek
mesh_terms: D000818:Animals; D044822:Biodiversity; D005399:Fishes / Q000469:parasitology*; D010271:Parasites / Q000145:classification* / Q000302:isolation & purification*; D012621:Seasons