Mohamed bin Zayed Species project number 152510387

Conservation of the endangered Iberian toothcarp Aphanius iberus in the threatened habitats at the edge of it distribution.

CONSERVATION OF THE ENDANGERED IBERIAN TOOTHCARP APHANIUS IBERUS IN THE THREATENED HABITATS AT THE EDGE OF ITS DISTRIBUTION

The Iberian toothcarp, Aphanius iberus, is distributed over twenty isolated populations along the Spanish Mediterranean coast between Catalonia and Andalusia. A unique population of Iberian toothcarp in Andalusia is located in the medium-lower basin of the Adra River (Almería, Spain). The conservation status is endangered by the Spanish National Catalogue of Endangered Species (Doadrio 2002) and the IUCN red list (IUCN 2015)⁠.
The population of Andalusia is distributed in two subpopulations, but they are not genetically distinct (Doadrio & Fernández-Delgado, pers. comm.) despite being spatially isolated, which points to the existence of connectivity between them in the past. The habitats, in which the species inhabits, are: i) Adra River, and associated traditional irrigation infrastructures and, ii) the coastal wetland of Albuferas de Adra. Each habitat presents specific characteristics and threats by human management and intensification of land uses. The Adra River and Albuferas de Adra are both natural habitats, which have been degraded by human uses and activities. Artificial habitats consist of irrigation ponds above-ground level, as well as irrigation channels connected to the Adra River. At present, the majority of these channels have been replaced by piped waterways.
We will evaluate the main threats to Aphanius iberus and promote management measures to restore and conserve the species' habitats:
- Adra River. Inadequate management by institutions has led to the alteration of river dynamic causing the loss of refuge habitats. We will build an irrigation pond that will function as a reservoir connected with the permanent reach through an input and output channel.
- Albuferas de Adra. Intensive agriculture negatively influences the ecosystem dynamic, strongly impacting the species (Casas et al. 2011). Moreover, carp introduction is expected to produce more adverse effects, therefore, evaluation is necessary to take appropriate measures for the eradication of this exotic species. ⁠
- Irrigation ponds and channels. Infrastructure modernization eliminated pond connectivity (e.g. channels), isolating populations which are progressively lost due to pond management, with no possibility of recolonization. In addition isolated populations will suffer demographic processes such as genetic isolation. Assessing these repercussions will allow us to perform actuations for connecting ponds (e.g., recuperation of channel sections).
- Intrapopulation genetic variability should be increased through the translocation of individuals from the better conserved subpopulations (Doadrio & Fernández-Delgado, pers. comm.), following restoration of natural habitats.
- The project will also conduct a campaign for volunteer recruitment, awareness-raising and dissemination, especially directed at children and farmers.

The next steps require the participation of different public institutions and will consist of:
1) Restoring river vegetation and dynamic which will strongly impact aquatic fauna during execution, however, individuals occupying the new pond will be able to recolonize the restored river.
2) Eradicating carp in Albuferas.
3) Maintaining connectivity between ponds and channels for individual dispersal and flux. We recommend monitoring and maintaining the population reservoir in Punta Entinas, since translocation of individuals from this stock to the original habitats could be necessary in case of an important disturbance.