Delimiting priorities while biodiversity is lost: Rio’s seasonal killifishes on the edge of survival

Abstract

The coastal plains of the Rio de Janeiro State, south-eastern Brazil, have been considered an important hotspot of aplocheiloid killifish diversity. A conservation status assessment based on 17 years of field studies directed to record habitat decline indicates that five species of seasonal killifish, Leptolebias marmoratus, Nematolebias papilliferus, Notholebias cruzi, Notholebias fractifasciatus and Ophthalmolebias constanciae, distributed among three areas of endemism, are on the edge of survival. Conservation priority, focusing on five remnant isolated locations where those species occur, was evaluated on the basis of the phylogenetic diversity content of each location established through a phylogenetic base containing data on relationships of 118 cynolebiasine species, including all species endemic to Rio. Data on species diversity for each area and data on morphological uniqueness were subsequently compared and discussed. The Barra de São João pool, in the São João-Cabo Frio area, habitat of Nematolebias whitei, No. cruzi, O. constanciae, concentrates the highest value for conservation proposal, followed by the Inoã pool, in the Maricá area, habitat of Ne. papilliferus and No. fractifasciatus. However, in case of the Barra de São João pool being effectively preserved, it is recommended to concentrate efforts to preserve the Cava swamp as a second priority, since although the latter location showing the lowest individual value, Cava swamp and Barra de São João pool together sum a higher phylogenetic diversity index by preserving more distinct cynolebiasine lineages.