Historical occurrences of diadromous fishes in French rivers between 1750 and 1980

Description :

 
The dataset provides historical occurrences of diadromous fishes in French rivers between 1750 and 1980. The dataset contains 1830 observations of 8 diadromous taxa, collected from historical sources by the Fluvial Hydroecology team (HEF) (HYCAR Research Unit - INRAE - Antony) since 2007.
To allow anyone to use this dataset, we have released the data to the public domain under a Creative Commons CC-BY 4.0 (http://creativecommons.org/licenses/by/4.0/legalcode). If you use these data for a scientific paper, please cite the dataset following the applicable citation norms and/or consider us for co-authorship. We are always happy to provide more information or know how you have used the data, so feel free to contact us via the contact information provided in the contact metadata section.

Link GBIF portal : https://www.gbif.org/dataset/a1db3e3d-517f-4063-bf41-65bf12f6e5ab

Project :
Title : Development of metric based on diadromous fishes in France
Abstract : This project aimed to develop a new metric based on amphihalin fish in France. This metric is independent of the fish indicators currently used in France(IPR and IPR+) and should be used as a complementary index to assess downstream network connectivity.

The first step of this project was to collect historical data. The created database gathers for each observation: the name of taxon, a date and a locality, as well as information about the data accuracy and the bibliographic source. Due to a lack of data on eel's historical distribution, we used modelled data from the IPR fish model (Oberdorff et al. (2001)) as a proxy. The data were then projected with GIS to produce historical distribution maps for each taxon.

In a second step, we defined a calculation mode for the metric. The metric is a ratio between the current richness and the potential richness in migratory fish. A null score corresponds to a loss of the entire migratory community and the maximum score corresponds to a maintaining of the community. This index is calculated with presence/absence data and doesn't take into account species abundance. Consequently, a large decrease in species abundance has no impact on the index as long as the species hasn't disappeared. In the same way, a punctual occurrence of a single individual is considered as a true presence in the index. 9 taxa are included in the index calculation: the shad (grouping of Alosa alosa and Alosa fallax), the lampreys (grouping of Lampetra fluviatilis and Petromyzon marinus), the mullets (grouping of Liza ramada and Chelon labrosus), the sturgeon (Acipenser sturio), the european flounder (Platichthys flesus), the houting (Coregonus oxyrinchus), the smelt (Osmerus eperlanus), the salmonids (grouping of Salmo salar and Salmo trutta trutta) and eel (Anguilla anguilla). Two versions of the metric are available, including eels or not. The index is computed at the surface water bodies scale as defined by the Water Framework Directive.

Finally, we analyzed the response of the metric to different environmental pressures. Results show that the metric is sensitive to three main factors: the downstream maximum falling height, the modification of hydrological regime at the local scale and the ratio between the sum of the falling heights of the downstream barriers and the site altitude. We concluded that the metric we developed clearly integrates breaks in continuity at the downstream network scale, which are responsible for a loss of migratory fish communities.
Funding : This work was supported and funded by the French Office for Biodiversity (OFB) in the frame of the "Programme 2016/2018 – Thème Etat, fonctionnement et services des écosystèmes aquatiques - Action n° 21". OFB also played an important role in the collection of current diadromous fish distribution data through electrofishing campaigns and local expertise.
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Dates publication :

Premiere diffusion : 09/04/2021 

Dernière mise à jour : 08/04/2022