Proceedings of the National Academy of Sciences of the United States of America, Jan 19, 2022
Raposeiro et al. (1) conclude that human occupation of the Azores islands began between 700 and 8... more Raposeiro et al. (1) conclude that human occupation of the Azores islands began between 700 and 850 CE, causing widespread landscape disturbance and raising doubts about the islands’ presumed pristine nature when the Portuguese arrived. However, previous paleoecological studies from Flores, Pico, and S~ ao Miguel Islands (Table 1) show that permanent changes in the vegetation occurred only after the early 15th century. The authors’ work also shows the permanent decline, to the lowest levels, in arboreal pollen on Corvo and Flores occurring during Portuguese occupation, not before. So, how would cereal cultivation, livestock grazing, and settlements be possible without deforestation—the hallmark of Norse settlements elsewhere (2)? The authors argue that these early settlements were extensive. Citing Nogu e et al. (6), who never mention such early settlements, they argue that these led to profound environmental and ecological disturbance. Nevertheless, they do recognize that such extensive occupation, persisting up to the 15th century, should have 1) been detected by the arriving Portuguese and mentioned in historical reports and 2) left clear archeological evidence.
The growth of scientific knowledge in the natural sciences in the nineteenth century to a large e... more The growth of scientific knowledge in the natural sciences in the nineteenth century to a large extent depended on networking and communication between naturalists. Our case-study illustrates such forms of scientific communication using a social network analysis (SNA) approach for studying the relationships of the Reverend Richard Thomas Lowe, an English naturalist who lived in Madeira from 1826 to 1852, and continued to visit until his death in a shipwreck in 1874. During his lifetime, he established a network of contacts mainly in the United Kingdom and in Madeira, which enabled him to develop and publish his pioneering work on the local flora, including A manual flora of Madeira and the adjacent islands of Porto Santo and the Desertas.
Angiosperms present an astonishing diversity of genome sizes that can vary intra‐ or interspecifi... more Angiosperms present an astonishing diversity of genome sizes that can vary intra‐ or interspecifically. The remarkable new cytogenomic data shed some light on our understanding of evolution, but few studies were performed with insular and mainland populations to test possible correlations with dispersal, speciation, and adaptations to insular environments. Here, patterns of cytogenomic diversity were assessed among geographic samples (ca. 114) of Crithmum maritimum (Apiaceae), collected across the Azores and Madeira archipelagos, as well as in adjacent continental areas of Portugal. Using flow cytometry, the results indicated a significant intraspecific genome size variation, spanning from reduced sizes in the insular populations to larger ones in the mainland populations. Moreover, there was a tendency for an increase in genome size along the mainland populations, associated with lower temperatures, higher precipitation, and lower precipitation seasonality. However, this gradient might be the result of historic phylogeographical events associated with previous dispersal and extinction of local populations. Overall, our findings provided evidence that smaller genome sizes might play a critical role in the colonization of islands, corroborating other studies that argue that organisms with smaller genomes use fewer resources, having a selective advantage under insular environments. Although further studies are needed to improve our understanding of the mechanisms underlying genome size evolution on islands, conservation strategies must be promoted to protect the rich cytogenomic diversity found among C. maritimum populations, which occur in coastal areas that are particularly threatened by human activity, pollution, invasive species, and climate changes.
Proceedings of the National Academy of Sciences of the United States of America, Jan 19, 2022
Raposeiro et al. (1) conclude that human occupation of the Azores islands began between 700 and 8... more Raposeiro et al. (1) conclude that human occupation of the Azores islands began between 700 and 850 CE, causing widespread landscape disturbance and raising doubts about the islands’ presumed pristine nature when the Portuguese arrived. However, previous paleoecological studies from Flores, Pico, and S~ ao Miguel Islands (Table 1) show that permanent changes in the vegetation occurred only after the early 15th century. The authors’ work also shows the permanent decline, to the lowest levels, in arboreal pollen on Corvo and Flores occurring during Portuguese occupation, not before. So, how would cereal cultivation, livestock grazing, and settlements be possible without deforestation—the hallmark of Norse settlements elsewhere (2)? The authors argue that these early settlements were extensive. Citing Nogu e et al. (6), who never mention such early settlements, they argue that these led to profound environmental and ecological disturbance. Nevertheless, they do recognize that such extensive occupation, persisting up to the 15th century, should have 1) been detected by the arriving Portuguese and mentioned in historical reports and 2) left clear archeological evidence.
The growth of scientific knowledge in the natural sciences in the nineteenth century to a large e... more The growth of scientific knowledge in the natural sciences in the nineteenth century to a large extent depended on networking and communication between naturalists. Our case-study illustrates such forms of scientific communication using a social network analysis (SNA) approach for studying the relationships of the Reverend Richard Thomas Lowe, an English naturalist who lived in Madeira from 1826 to 1852, and continued to visit until his death in a shipwreck in 1874. During his lifetime, he established a network of contacts mainly in the United Kingdom and in Madeira, which enabled him to develop and publish his pioneering work on the local flora, including A manual flora of Madeira and the adjacent islands of Porto Santo and the Desertas.
Angiosperms present an astonishing diversity of genome sizes that can vary intra‐ or interspecifi... more Angiosperms present an astonishing diversity of genome sizes that can vary intra‐ or interspecifically. The remarkable new cytogenomic data shed some light on our understanding of evolution, but few studies were performed with insular and mainland populations to test possible correlations with dispersal, speciation, and adaptations to insular environments. Here, patterns of cytogenomic diversity were assessed among geographic samples (ca. 114) of Crithmum maritimum (Apiaceae), collected across the Azores and Madeira archipelagos, as well as in adjacent continental areas of Portugal. Using flow cytometry, the results indicated a significant intraspecific genome size variation, spanning from reduced sizes in the insular populations to larger ones in the mainland populations. Moreover, there was a tendency for an increase in genome size along the mainland populations, associated with lower temperatures, higher precipitation, and lower precipitation seasonality. However, this gradient might be the result of historic phylogeographical events associated with previous dispersal and extinction of local populations. Overall, our findings provided evidence that smaller genome sizes might play a critical role in the colonization of islands, corroborating other studies that argue that organisms with smaller genomes use fewer resources, having a selective advantage under insular environments. Although further studies are needed to improve our understanding of the mechanisms underlying genome size evolution on islands, conservation strategies must be promoted to protect the rich cytogenomic diversity found among C. maritimum populations, which occur in coastal areas that are particularly threatened by human activity, pollution, invasive species, and climate changes.
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