scholarly journals Extinction of the Thylacine

2021 ◽  
Author(s):  
Barry W. Brook ◽  
Stephen R. Sleightholme ◽  
Cameron R. Campbell ◽  
Ivan Jarić ◽  
Jessie C. Buettel
Keyword(s):  
Intrinsic Value ◽  
Late 20Th Century ◽  
European Settlement ◽  
Large Island ◽  
Extinction Event ◽  
Spatio Temporal ◽  
Distributional Dynamics ◽  
Late Survival ◽  
Captive Animal ◽  
Modelling Approach

AbstractThe Thylacine (Thylacinus cynocephalus), or ‘Tasmanian tiger’, is an icon of recent extinctions, but the timing of its final demise is shrouded in controversy. Extirpated from mainland Australia in the mid-Holocene, the large island of Tasmania became the species’ final stronghold. Following European settlement, the Thylacine was heavily persecuted and pushed to the margins of its range. The last captive animal died in 1936, but numerous sightings were reported thereafter. Here we collate and characterize the type, quality, and uncertainty of over a thousand unique sighting records of Thylacines since 1910. We use this novel and unique curated database to underpin a detailed reconstruction and mapping of the species’ spatio-temporal distributional dynamics, to pinpoint refugia of late survival and estimate the bioregional patterns of extirpation. Contrary to expectations, the inferred extinction window is wide and relatively recent, spanning from the 1980s to the present day, with extinction most likely in the late 1990s or early 2000s. While improbable, these aggregate data and modelling suggest some chance of ongoing persistence in the remote wilderness of the island. Although our findings for this iconic species hold intrinsic value, our new spatio-temporal mapping of extirpation patterns is also applicable more generally, to support the conservation prioritization and search efforts for other rare taxa of uncertain status.Significance statementLike the Dodo and Passenger Pigeon before it, the Thylacine has become an iconic symbol of human-caused extinction. Even today, reports of the Thylacine’s possible ongoing survival in remote regions of Tasmania are newsworthy and continue to capture the public’s imagination, with much debate over whether the extinction event has yet occurred and if so, when? We show, using a unique and robust spatio-temporal mapping and modelling approach, underpinned by the world’s first sightings database (from 1910-present day), that the Thylacine likely persisted until the late 20th century, with some possibility of ongoing survival.

Transboundary Extreme Ultrafine Dust Events in East Asia under a Warmer Monsoon Climate

2020 ◽  
Author(s):  
Gwangyong Choi
Keyword(s):  
East Asia ◽  
Large Scale ◽  
Northern China ◽  
Cold Season ◽  
Reanalysis Data ◽  
Monsoon Climate ◽  
Late 20Th Century ◽  
Spatio Temporal ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Dust Events

<p>Since the late 20th century East Asia has frequently experienced unprecedented transboundary extreme ultrafine dust events (TEUDEs) due to a fast economic development based on significant amount of fossil fuel consumption. In this study, spatio-temporal patterns of the TEUDEs in East Asia and the roles of synoptic climate patterns and changing large-scale atmospheric circulation systems in exacerbating the anthropogenic atmospheric pollution events causing considerable human deaths are examined. Analyses of the Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua and Terra aerosol optical depth (AOD) data (2000-2019) clearly show that the pollutants are produced mainly in northern China and move toward central Korea and southern Japanese islands during cold seasons when coals consumption soars for heating. Synoptic climatic maps drawn from the NCEP-NCAR I reanalysis data for multiple TEUDEs demonstrate that a north clockwise- south anticlockwise wind vector anomaly pattern in cold seasons formed by less southward meandering of Siberian High pressure (SH) helps the stagnation of significant amount of ultrafine dusts over East Asia. It is also notable that the long-term poleward retreating trend of cold season circumpolar vortex, which is associated with less frequent gusty wind flow from the SH, may provide a favorable condition for intense, long-lasting TEUDEs across East Asia under a warmer monsoon climate.</p>

In Defense of the Human Difference

2018 ◽  
Vol 15 (1) ◽  
pp. 101-115
Author(s):  
Sean J. McGrath ◽  
Keyword(s):  
Intrinsic Value ◽  
Moral Worth ◽  
Human Consciousness ◽  
Moral Discernment ◽  
Abuse And Neglect ◽  
Extinction Event ◽  
Human Difference ◽  
Human Capacity ◽  
The Difference ◽  
Material Conditions

Against the prevalent trend in eco-criticism which is to deny the human difference, I summon a set of untimely tropes from metaphysics in the interest of advancing an ecological humanism: the difference in kind between human consciousness and animal sensibility; the uniquely human capacity for moral discernment; and the human being’s peculiar freedom from the material conditions of existence. While I agree with eco-critics who argue that anthropocenic nature is not only finite, but sick: sickened by our abuse and neglect, I disagree that this abuse is simply a result of insisting on the human difference (“anthropocentrism”), nor is species egalitarianism the way forward. On the contrary, the eco-collapse, referred to as the sixth great extinction event, is the consequence of a general disavowal of the human’s special call to take responsibility for the relation between the human and the non-human, and only a re-awakening of this responsibility can restore health to anthropocenic nature. The non-human cannot effect this restoration, for that is not its vocation. A difference in vocation is not necessarily a difference in moral worth, and so the human difference does not justify denying the “intrinsic value” of the non-human. Humanity is uniquely responsible both for the mess we are in and for cleaning it up.

Size matters: diatom establishment and extirpation timing in the Laurentian Great Lakes has been influenced by cell size

2020 ◽  
Vol 42 (3) ◽  
pp. 255-264
Author(s):  
Andrew J Bramburger ◽  
Euan D Reavie ◽  
Gerald V Sgro ◽  
Lisa R Estepp ◽  
Victoria L Shaw Chraïbi ◽  
...  
Keyword(s):  
Great Lakes ◽  
Cell Size ◽  
Propagule Pressure ◽  
Multiple Stressors ◽  
Nutrient Status ◽  
Laurentian Great Lakes ◽  
Late 20Th Century ◽  
European Settlement ◽  
Species Invasions ◽  
Fossil Records

Abstract The Laurentian Great Lakes are among the planet’s fastest-warming lakes. Recent paleolimnological studies have shown changes in the diatom community of the system, including shifts towards taxa characteristic of strongly stratified systems and ongoing cell-size diminution. Relationships between species’ cell size and establishment in—or extirpation from—the system have not been addressed. Examining patterns of establishment and extirpation provides insight into the effects of multiple stressors at the ecosystem scale. We evaluate the timing of the establishment or extirpation of diatom taxa from fossil records post-European settlement within the Great Lakes as a function of cell size. Relationships between establishment or extirpation date and cell size were not random, and were best expressed as cubic curves. Generally, large taxa became established early in the record, while establishments of smaller taxa continued apace until the late 20th century. Extirpations of taxa of all sizes accelerated in the late 20th and early 21st centuries, and large-celled taxa were disproportionately extirpated over the last two decades. We discuss the implications of these relationships on the overall cell-size characteristics of the community, and consider the influences of propagule pressure, nutrient status, species invasions, and climate change upon diatom establishment and extirpation.

scholarly journals Post-Clovis survival of American Mastodon in the southern Great Lakes Region of North America

2009 ◽  
Vol 72 (3) ◽  
pp. 359-363 ◽  
Author(s):  
Neal Woodman ◽  
Nancy Beavan Athfield
Keyword(s):  
North America ◽  
Younger Dryas ◽  
Bone Collagen ◽  
Large Mammals ◽  
Cultural Complex ◽  
Time Period ◽  
Accelerator Mass Spectrometer ◽  
Extinction Event ◽  
Mammut Americanum ◽  
Late Survival

AbstractThe end of the Pleistocene in North America was marked by a wave of extinctions of large mammals, with the last known appearances of many species falling between ca. 11,000–10,000 14C yr BP. Temporally, this period overlaps with the Clovis Paleoindian cultural complex (11,190–10,530 14C yr BP) and with sudden climatic changes that define the beginning of the Younger Dryas chronozone (ca. 11,000–10,000 14C yr BP), both of which have been considered as potential proximal causes of this extinction event. Radiocarbon dating of enamel and filtered bone collagen from an extinct American Mastodon (Mammut americanum) from northern Indiana, USA, by accelerator mass spectrometer yielded direct dates of 10,055 ± 40 14C yr BP and 10,032 ± 40 14C yr BP, indicating that the animal survived beyond the Clovis time period and into the late Younger Dryas. Although the late survival of this species in mid-continental North America does not remove either humans or climatic change as contributing causes for the late Pleistocene extinctions, neither Clovis hunters nor the climatic perturbations initiating the Younger Dryas chronozone were immediately responsible for driving mastodons to extinction.

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