Species extinction at the various environmental forcing in a stochastic ecosystem model

This paper considers a stochastic multi-species single resource population model. The stochastic model is obtained from perturbing the supply of resource by a time dependent force. We use analytical investigations and numerical simulations to study the dynamics of our model under chaotic and periodic environmental oscillations, and show that the stochastic dynamics of our model exhibits a strong dependence on initial parameters.

Effects of Dams on Vertebrate Diversity: A Global Analysis

Dams are crucial for water supply in human populations and are becoming more common globally for hydroelectric power generation. Dams alter natural habitats and their biodiversity; however, studies are inconclusive about their effects on them. This study aimed to examine the effects of dams on vertebrates and the determinants of changes in global biodiversity and their relationship with critical areas for conservation. We evaluated the effects of dams on vertebrate richness and abundance. We performed a meta-analysis based on 120 case studies. We evaluated the overall effect on richness and abundance and examined these effects regarding taxa, disturbance type, latitudinal zone, zoogeographic zone, biodiversity hotspots, dam size and purpose, and species extinction risk. We conducted an overall analysis that included all species, and then we conducted separate analyses for terrestrial and aquatic species. Dams had a negative effect on vertebrate richness but not on vertebrate abundance. These effects were influenced by larger dams with fragmentation and were more pronounced within hotspots and in countries with a low species extinction risk. Such negative effects were explained by terrestrial vertebrates (particularly birds and mammals) because species richness and the abundance of aquatic vertebrates (fish) were not affected by dams in any case. Our results showed that habitat fragmentation created by large dams changes vertebrate communities, negatively affecting species richness in some areas of conservation concern. We propose implementing reservoirs in areas where they would have a lower impact on biodiversity and avoiding large dams in priority areas for conservation and where endangered species inhabit.

Threat patterns and conservation status of endemic vascular flora in Argentina: a quantitative perspective

Global warming, coupled with habitat destruction and human activity, are accelerating the rates of species extinction worldwide. Species-extinction risk assessment, using the IUCN Red List categories, together with the study of the spatial patterns of biodiversity, are fundamental approaches to identify conservation priorities and targeting government decisions to mitigate impacts on biodiversity. Here, we analyzed threat levels of endemic species for the entire Argentinean vascular flora. Accordingly, we classified species following the IUCN threat categories and analyze threat levels on the different families, plant life-forms, and biogeographic regions of the country. We also analyzed spatial patterns of threat by means of macroecological modeling techniques, and explored the effectiveness of current protected areas in relation to the threatened endemics they actually included. The results showed that of the 1683 Argentinean endemic taxa, 800 species were here categorized under threat (VU, EN, or CR) (~47%). Families with the highest number of threatened species were also those with the highest number of endemics; herbs and climbing plants presented significantly higher threat levels, and among biogeographic provinces, the most affected in terms of threat proportion were the Altoandina, Yungas, and Paranaense. In addition, different hotspots of threatened endemism were detected, mainly associated with mountainous areas with high altitudinal heterogeneity; of these, only nearly half are included, at least partially, within a protected area. An up-to-date species list of Argentinean endemics, including their proposed conservation status, is also provided. This work seeks to contribute to the knowledge on geographical patterns of the Argentinean flora and its conservation, complementing the information published in the Flora of Argentina.

Song of the Earth

This book is a scientific, historical, and philosophical narrative for general readers that explores the relationship between humans and the Earth and the geologic principles of time, plate tectonics, and change in life forms. Illustrated with striking historical maps, figures, and pictures, this comprehensive work can be read as a thrilling biography of the Earth itself, including narrative sections on the lives of pioneering geologists; the reality and sublimity of geologic time; the birth, destruction, and rebirth of the planet and its atmosphere over repeated cycles spanning some 4-plus billion years; the science underlying both mountain building and oceanic evolution; the influence of climate change and species extinction on the development of the Earth; and the interplay between not only how Earth has influenced life but how life, in turn, has distinctly shaped our planet.

The two extinctions of the Carolina Parakeet Conuropsis carolinensis

Summary Due to climate change and habitat conversion, estimates of the resulting levels of species extinction over the next century are alarming. Devising conservation solutions will require many different approaches, including examining the extinction processes of recently extinct species. Given that parrots are one of the most threatened groups of birds, information regarding parrot extinction is pressing. While most recent parrot extinctions have been island endemics, the Carolina Parakeet Conuropsis carolinensis had an 18th-century range covering nearly half of the present-day United States, yet mostly disappeared by the end of the 19th century. Despite a great deal of speculation, the major cause of its extinction remains unknown. Establishing the date when a species went extinct is one of the first steps in determining what caused their extinction. While there have been estimates of their extinction date, these analyses used a limited dataset and did not include observational data. We used a recently published, extensive dataset of Carolina Parakeet specimens and observations combined with a Bayesian extinction estimating model to determine the most likely extinction dates. By considering each of the two subspecies independently, we found that they went extinct ˜30 years apart: the western subspecies C. c. ludovicianus going extinct around 1914 and the eastern subspecies C. c. carolinensis either in the late 1930s or mid-1940s. Had we only considered all observations together, this pattern would have been obscured, possibly missing a major clue in solving the mystery of the parakeet’s extinction. Since the Carolina Parakeet was a wide-ranging species that went extinct during a period of rapid agricultural and industrial expansion, conditions that mirror those occurring in many parts of the world where parrot diversity is highest, any progress we make in unraveling the mystery of their disappearance may be vital to modern conservation efforts.

Archive Trouble

In an era when the possibility of species extinction is more importunate than ever, Beckett’s 1958 play, Endgame, carries a profound sense of immediacy. This article considers the ‘afterlife’ subtended by the play in terms of its post-apocalyptic premise—traditionally, the provenance of the science fiction genre. Using Adorno’s 1961 reading of Endgame, which brushes aside any filiations with “childish science fiction,” the argument pivots on the ‘paring-down’ operations that deprive the drama of most of its resources. Since the latter includes the archivising operations of memory, their breakdown makes the play’s insistent SF allusions both inescapable and radically untenable.

The Mom and the Many: Animal Subplots and Vulnerable Characters in Ducks, Newburyport

This article examines Lucy Ellmann's encyclopedic novel Ducks, Newburyport (2019) in the context of debates on modernist legacies, animal characters, and climate fiction. It pays particular attention to the text's signature strategy of including anecdotes about nonhuman creatures exposed to distinct forms of violence, anecdotes that reveal the concerns of the human narrator and her daughter but also highlight other animals, their unfamiliar phenomenologies, and their cautious cross-species partnerships. More specifically, the article tracks individual animals across the novel's pages and reconstructs their semiautonomous subplots as they unfold in a world characterized by animal cruelty, species extinction, and industrial labor. By forcing us to consider the perspectives of creatures like Jim, Mishipeshu, Audrey, and Gracia, Ellmann's narrative reminds us that the climate emergency does not just destabilize a shared geological environment but also endangers multiple and heterogeneous biological worlds.