Effects of enhanced hydrological connectivity on Mediterranean salt marsh fish assemblages with emphasis on the endangered Spanish toothcarp (Aphanius iberus)
- Published
- Accepted
- Subject Areas
- Biodiversity, Conservation Biology, Ecology, Marine Biology
- Keywords
- distance to the sea, connectivity, isolation, salt marsh rehabilitation, fish diversity, Aphanius iberus, fish dispersal
- Copyright
- © 2016 Prado et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2016. Effects of enhanced hydrological connectivity on Mediterranean salt marsh fish assemblages with emphasis on the endangered Spanish toothcarp (Aphanius iberus) PeerJ Preprints 4:e2518v1 https://doi.org/10.7287/peerj.preprints.2518v1
Abstract
The hydrological connectivity between the salt marsh and the sea was partially restored in a Mediterranean wetland containing isolated ponds resulting from former salt extraction and aquaculture activities. A preliminary assessment provided evidence that ponds farther from the sea hosted very large numbers of the endangered Spanish toothcarp, Aphanius iberus, suggesting that individuals had been trapped and consequently reach unnaturally high densities. In order to achieve both habitat rehabilitation and toothcarp conservation, efforts were made to create a gradient of hydrologically connected areas, including isolated fish reservoirs, semi-isolated, and connected salt marsh–sea areas that could allow migratory movements of fish and provide some protection for A. iberus. The fish community was monitored prior to, and for three years after rehabilitation. Results showed an increase in the number of fish species within semi-isolated areas (Zone A), relative to connected areas (Zone B), while at the assemblage level, structural differences between zones were higher than interannual variability. GLMs evidenced that distance to the sea was the most important variable explaining the local diversity of the fish community after restoration, with occasional influence of other factors such as temperature, and depth. The abundance of A. iberus was consistently higher in semi-isolated areas at greater distances from the sea, but a decline occurred in both zones and in isolated reservoir ponds after restoration efforts, which may be attributable to dispersal to adjacent habitats, and to interannual differences in recruitment success. A negative effect of restoration works on fish population cannot be excluded, but the final outcome of the intervention likely needs a longer period .
Author Comment
This is a submission to PeerJ for review.
Supplemental Information
Annex I
Temporal changes in the study area. A) In 1860, the northern coast of the Alfacs Bay (see also Fig. 1) was fully fingered by salt marsh which connected with a much larger lacunar system (nowadays the Encanyissada and Tancada lagoons constitute remaining portions). B) In 1927 to C) 1954, the salt pans were already built but the loss of salt marsh area increases progressively. D) Full view of the abandoned fish farm before connectivity enhancement in 2011, and E) current aspect of the study area after rehabilitation works.