Genomic evidence of rapid,global-scale gene flow in a Sulfolobus species

Local populations of Sulfolobus islandicus diverge genetically with geographical separation, and this has been attributed to restricted transfer of propagules imposed by the unfavorable spatial distribution of acidic geothermal habitat. We tested the generality of genetic divergence with distance in Sulfolobus species by analyzing genomes of Sulfolobus acidocaldarius drawn from three populations separated by more than 8000 km. In sharp contrast to S. islandicus, the geographically diverse S. acidocaldarius genomes proved to be nearly identical. We could not link the difference in genome conservation between the two species to a corresponding difference in genome stability or ecological factors affecting propagule dispersal. The results provide the first evidence that genetic isolation of local populations does not result primarily from properties intrinsic to Sulfolobus and the severe discontinuity of its geothermal habitat, but varies with species, and thus may reflect biotic interactions that act after propagule dispersal.     

Obstetric violence as immigration injustice: A view from the United States and Colombia

In September 2020, Project South, along with numerous other organizations, released a report detailing abuses in a Georgia Detention Center – including forced hysterectomies. Whatever other factors are at play, one of them is an intrinsic connection between obstetric violence against pregnant migrants and immigration injustice. It is not incidental that these acts – in US detention centers, along the US-Mexico border, in Colombian hospitals and clinics – are being perpetrated on immigrant bodies. And it is not accidental or random which immigrant bodies are vulnerable to these violations. Understanding and confronting obstetric violence directed at pregnant migrants, though, requires reconceptualizing the nature of obstetric violence itself. In particular, we must recognize that obstetric violence against pregnant Latin American migrants in the United States and Colombia is a type of immigration injustice, a means to perpetrate immigration injustice, and a product of immigration injustice. As such, bioethicists need to collaborate with immigration scholars to resist it. After providing some background on the nature of obstetric violence and some ways it is perpetuated against pregnant migrants in the United States and Colombia, I will give a brief overview of how I conceptualize immigration justice. From there, I explain how this type of obstetric violence constitutes a type of immigration injustice, a means to perpetrate immigration injustice, and a product of immigration injustice. My hope is that this analysis motivates bioethicists throughout the Americas to engage with immigration scholars and activists to confront the issue more forcefully.     

Species turnover on a protected subtropical barrier island: a long-term study

Abstract. The commercial development that threatens the biodiversity of coastal habitats is particularly severe along the sandy shores of subtropical Florida. The objective of our study was to test the applicability of the equilibrium theory of island biogeography to Cayo-Costa Island, the largest protected barrier island remaining in peninsular Florida. Our null hypothesis was that there would be no change in the number and composition of native vascular plant species on Cayo-Costa 15 years after the first inventory of the island's flora. Our reinventory documents a total of 230 native species in 1990–92 compared to 255 native species in 1975–77. Immigrants were represented by twenty-eight new species, while extinctions totalled fifty-three species. These results indicate a turnover rate of approximately 2.7 species yr^-1 with an extinction rate of 3.5 species yr^-1 and an immigration rate of 1.9 species yr^-1. The net loss of 1.6 species yr^-1 suggests a non-equilibrium condition that is not readily explained by changes in habitat diversity associated with the documented patterns of shoreline erosion and deposition. Cayo-Costa's net loss of twenty-five native species (including one tree species and four shrub species) was localized mainly in those habitats where there had been a significant increase in the relative abundance of the naturalized weedy exotic species Schinus terebinthifolius and Casuarina equisetifolia . We conclude that the spread of naturalized weedy species limits the applicability of the equilibrium theory of island biogeography to species-rich subtropical barrier islands, even in cases where the islands are protected from human disturbance.     

An experimental examination of the effects of habitat quality on the dispersal and local abundance of the butterfly Parnassius smintheus

Abstract 1. Nectar flower abundance was manipulated through flower removal, and sex ratio was manipulated by moving individual butterflies within a series of nine alpine meadows. The movement and abundance of the butterfly Parnassius smintheus in the meadows were monitored using mark–release–recapture methods.
2. A total of 937 butterflies, 698 males and 239 females, was captured. There were 223 observed between-meadow movements. Fifty-two per cent of males and 35% of females moved among meadows.
3. The immigration of male butterflies was related positively to nectar flowers, host plant abundance, and female butterflies. Male emigration was not affected by any of the treatments. The number of males captured was related positively to nectar flowers and host plants but not affected by sex ratio. The number of resident male butterflies was greater in meadows containing flowers and was related positively to host plant abundance, but unaffected by sex ratio.
4. Flower removal, sex ratio, and abundance of Sedum had no significant effect on the abundance, movement, or residence time for female butterflies, in part due to small sample size.
5. The fact that males immigrate to higher quality meadows suggests that male butterflies are assessing meadow quality, either by sampling meadows or potentially from a distance using olfactory cues.