Habitat characterization and distribution area of the killfish Melanorivulus leali Costa, 2013 (Cyprinodontiformes: Rivulidae), an endangered species

Abstract

Melanorivulus leali is a non-annual rivulid endemic to Brazil, and the first species of the genus described in the Grande River drainage, Upper Paraná basin. Its distribution area has been intensely altered by sugarcane monoculture and urbanization, leaving only rare traces of the original vegetation remaining. For this reason, M. leali has been categorized as “vulnerable” by ICMBio. The present study aimed to complement information on the distribution, habitat characterization and main threats to the species, based on surveys conducted in the Pardo and Mogi-Guaçu rivers basins (São Paulo State). Two sampling expeditions were carried out at 26 sites, where strong anthropogenic influence was observed, including the presence of invasive alien species and agricultural activities. Individuals of Melanorivulus leali were collected at five sites: one in a sugarcane monoculture in Sertãozinho, at Santa Maria Ecological Station, and at São Simão Experimental Station, all under the influence of the Pardo River. The species occurs in small, shallow streams with clear water, abundant submerged aquatic macrophytes, leaf litter, mud or sand, high dissolved oxygen concentrations, despite the presence of alien species. Sites located within protected areas show natural hydrological connection with the Tamanduá stream, a tributary of the Pardo River. Thus, the records of M. leali were expanded, including the first record of the species in a protected area. The fact that 80% of the records are located inside a protected area highlights their importance for conserving aquatic biodiversity.