Stream macroalgal flora from Parnaíba River Basin, Brazil: reducing Wallacean shortfall

Abstract

The global biodiversity loss is a consensus. The biodiversity conservations shortfalls make conservation of biological diversity even more challenging. For many taxa, the knowledge about their distributions is deficient, and this is called the Wallacean shortfall. This situation is no different within algae biodiversity, especially in Brazil. There is still an enormous inequity of sample effort, as is the case of the Parnaíba River Basin (Northeast region), which had only 10 algal species in published (the lowest number of algal species reported among the main Brazilian basins). The present work had the objective of increasing the knowledge of algal flora in Brazil by conducting a taxonomic study of the stream macroalgal species of the Parnaíba River Basin. The sampling of macroalgae was carried out in 21 segments of streams from the Middle and Lower Parnaíba Basin, in the Piauí and Maranhão states. Macroalgae were manually removed and preserved in 4% formaldehyde. Environmental characteristics of each segment were measured in order to describe the sampling sites. The taxonomic survey of the macroalgal communities resulted in the identification of 38 taxa in total, of which 32 at a specific level; three vegetative groups; two sporophytic stages of red algae and one unidentified species. Among the 38 species recorded, 37 are new records for the Parnaíba River Basin. Following the same pattern, 23 species are new records for the Brazilian Northeast region, and Microcoleus lacustris represented the first report in Brazil. Despite the fact that it remains the Brazilian basin with the lowest number of algal species documented, this study contributed to the increase of almost five times the number of species sampled in the Parnaíba River Basin (from only 10 to 47 species). These data reinforce that the differences presented in algal diversity in the Brazilian regions are more related to the sampling effort than other factors (e.g. environmental characteristics, geographic distribution, biomes, among others). In addition, this survey illustrates not only the group's lack of information in the region but also shows the importance of this type of study as a tool for expanding the knowledge about biodiversity and its conservation.

A new epilithic stream species in Northeastern Brazil: Arnoldiella elbakyaniae (Cladophorales, Chlorophyta)

“…This region encompasses an ecotone that is under the natural influence of the Caatinga and Cerrado Biomes. The sample was found in a region with few records of algae (Auricchio et al 2019). Although the analyzed material is abundant, the difficulty of access to the site and the environmental changes that the region has been suffering have not allowed new access to the material.…”

Periphytic algal flora of the lower Doce river basin after ore tailings flow, Espírito Santo State, Brazil: Sampling design and methods

“…Menezes et al (2015) recorded 4,747 species of algae and cyanobacteria for Brazil. This number is increasing even more with several study efforts, such as the algae flora of streams in the Parnaíba River basin (Auricchio et al 2019), checklist of the Cosmarium in Brazil (Biolo & Bicudo 2018), floristic survey of urban parks (D'alessandro & Nogueira 2017), and descriptions of new species (Ramos et al 2017, Lehmkuhl et al 2019, Ramos et al 2019, Zorzal-Almeida et al 2020. One of the most relevant studies about Brazilian microalgae flora is the survey of the 'Algal Flora of the Parque Estadual das Fontes do Ipiranga (PEFI)', which started in 1962 and registered 869 taxa in 42 fascicles (Bicudo 2020).…”