Distribution and Endemism Areas of Bonamia Thouars (Convolvulacea) in Brazil.

Brazil harbors the highest richness of Convolvulaceae with 424 species recognized mainly distributed in the Amazon, Atlantic Forest, Caatinga and Cerrado phytogeographic domains. Seventeen of these species are representatives of Bonamia, with ten endemic to the country. The aim of the study was to map the distribution of this group to understand its richness, its sampling and detecting areas of endemism, valuable information for conservation. We collected data gathered from herbaria and from the online database. The data were refined (1) excluding of records not at the species level; (2) records with no identification of collection site or with only the identification of the state of collection. There was calculated the richness, the number of records and an estimate of richness per cell. We conducted a parsimony analysis of endemism for distribution analysis. Finally, the knowledge of richness for the species was analyzed. There were gathered 420 occurrence records, in 87 grid cells. Most grid cells observed in the study presented one species. Two endemic areas were found for the genus. The results contribute to the understanding of the distribution of the group in Brazil, highlighting shortfalls in collections.

Investigating non-fungal eukaryotic diversity in snow in the Antarctic Peninsula region using DNA metabarcoding.

Snow is a unique microhabitat, despite being a harsh environment, multiple life forms have adapted to survive in it. While algae, bacteria and fungi are dominant microorganisms in Antarctic snow, little is known about other organisms that may be present in this habitat. We used metabarcoding to investigate DNA sequence diversity of non-fungal eukaryotes present in snow obtained from six different sites across the Maritime Antarctica. A total of 20 taxa were assigned to obtained sequences, representing five Kingdoms (Chromista, Protozoa, Viridiplantae and Metazoa) and four phyla (Ciliophora, Cercozoa, Chlorophyta and Cnidaria). The highest diversity indices were detected in Trinity Peninsula followed by Robert Island, Arctowski Peninsula, Deception Island, King George Island and Snow Island. The most abundant assignments were to Trebouxiophyceae, followed by Chlamydomonas nivalis and Chlamidomonadales. No taxa were detected at all sites. Three potentially new records for Antarctica were detected: two Ciliophora (Aspidisca magna and Stokesia sp.) and the green algae Trebouxia potteri. Our data suggested that similarities found between the sites may be more related with snow physicochemical properties rather than geographic proximity or latitude. This study provides new insights into the diversity and distribution of eukaryotic organisms in Antarctic snow.

Fairy ring disease affects epiphytic algal assemblages associated with the moss Sanionia uncinata (Hedw.) Loeske (Bryophyta) on King George Island, Antarctica.

Since the nineteenth century, a ring-forming disease attacking Antarctic mosses has been reported. However, to date, only the effects on the mosses themselves are known. In this study, we used DNA metabarcoding to investigate the effects on the moss epiphytic algal community at different stages of disease progression. As the disease progressed, algal species richness decreased, although overall abundance was not significantly affected. Prasiolales appeared unaffected, whereas Ulotrichales were more sensitive. Trebouxiales dominated the advanced disease stage, suggesting a possible benefit from the disease, either through the elimination of competition or creation of new niches. Infection is responsible for moss death, leading to habitat loss for other organisms, but pathogenic effects on algae cannot be ruled out. Our data indicate that the disease not only impacts mosses but also other groups, potentially resulting in loss of Antarctic biodiversity. This study provides the first report of the disease effects on epiphytic algal communities of Antarctic bryophytes.

Diversity and Ecology of Chlorophyta (Viridiplantae) Assemblages in Protected and Non-protected Sites in Deception Island (Antarctica, South Shetland Islands) Assessed Using an NGS Approach.

Assessment of the diversity of algal assemblages in Antarctica has until now largely relied on traditional microbiological culture approaches. Here we used DNA metabarcoding through high-throughput sequencing (HTS) to assess the uncultured algal diversity at two sites on Deception Island, Antarctica. The first was a relatively undisturbed site within an Antarctic Specially Protected Area (ASPA 140), and the second was a site heavily impacted by human visitation, the Whalers Bay historic site. We detected 65 distinct algal taxa, 50 from within ASPA 140 and 61 from Whalers Bay. Of these taxa, 46 were common to both sites, and 19 only occurred at one site. Algal richness was about six times greater than reported in previous studies using culture methods. A high proportion of DNA reads obtained was assigned to the highly invasive species Caulerpa webbiana at Whalers Bay, and the potentially pathogenic genus Desmodesmus was found at both sites. Our data demonstrate that important differences exist between these two protected and human-impacted sites on Deception Island in terms of algal diversity, richness, and abundance. The South Shetland Islands have experienced considerable effects of climate change in recent decades, while warming through geothermal activity on Deception Island itself makes this island one of the most vulnerable to colonization by non-native species. The detection of DNA of non-native taxa highlights concerns about how human impacts, which take place primarily through tourism and national research operations, may influence future biological colonization processes in Antarctica.