scholarly journals A paradoxical knowledge gap in science for critically endangered fishes and game fishes during the sixth mass extinction

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christopher S. Guy ◽  
Tanner L. Cox ◽  
Jacob R. Williams ◽  
Colter D. Brown ◽  
Robert W. Eckelbecker ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Species Conservation ◽  
Marine Species ◽  
Scientific Productivity ◽  
Scientific Output ◽  
Critically Endangered ◽  
Extinction Rate ◽  
Sixth Mass Extinction ◽  
Game Fish ◽  
The Difference

AbstractDespite unprecedented scientific productivity, Earth is undergoing a sixth mass extinction. The disconnect between scientific output and species conservation may be related to scientists studying the wrong species. Given fishes have a high extinction rate, we assessed the paradox between scientific productivity and science needed for conservation by comparing scientific output created for critically endangered fishes and game fishes. We searched 197,866 articles (1964–2018) in 112 journals for articles on 460 critically endangered fishes, 297 game fishes, and 35 fishes classified as critically endangered and game fish—our analysis included freshwater and marine species. Only 3% of the articles in the final database were on critically endangered fishes; 82% of critically endangered fishes had zero articles. The difference between the number of articles on game fishes and critically endangered fishes increased temporally with more articles on game fishes during the extinction crisis. Countries with 10 or more critically endangered fishes averaged only 17 articles from 1964 to 2018. Countries with the most critically endangered fishes are most in need of science. More scientific knowledge is needed on critically endangered fishes to meet the challenges of conserving fishes during the sixth mass extinction.

scholarly journals Thinking about the Biodiversity Loss in This Changing World

Geosciences ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 370
Author(s):  
Maria Rita Palombo
Keyword(s):  
Big Five ◽  
Mass Extinction ◽  
Negative Impact ◽  
Biodiversity Loss ◽  
Wildlife Trade ◽  
Ecosystem Structure ◽  
Extinction Rate ◽  
Mass Extinctions ◽  
Species Introduction ◽  
Sixth Mass Extinction

Extinction of species has been a recurrent phenomenon in the history of our planet, but it was generally outweighed in the course of quite a long geological time by the appearance of new species, except, especially, for the five geologically short times when the so-called “Big Five” mass extinctions occurred. Could the current decline in biodiversity be considered as a signal of an ongoing, human-driven sixth mass extinction? This note briefly examines some issues related to: (i) The hypothesized current extinction rate and the magnitude of contemporary global biodiversity loss; (ii) the challenges of comparing them to the background extinction rate and the magnitude of the past Big Five mass extinction events; (iii) briefly considering the effects of the main anthropogenic stressors on ecosystems, including the risk of the emergence of pandemic diseases. A comparison between the Pleistocene fauna dynamics with the present defaunation process and the cascading effects of recent anthropogenic actions on ecosystem structure and functioning suggests that habitat degradation, ecosystem fragmentation, and alien species introduction are important stressors increasing the negative impact on biodiversity exerted by anthropogenic-driven climate changes and their connected effects. In addition, anthropogenic ecological stressors such as urbanization, landscapes, and wildlife trade, creating new opportunities for virus transmission by augmenting human contact with wild species, are among the main factors triggering pandemic diseases.

scholarly journals The ecology of plant extinction: rates, traits and island comparisons

Oryx ◽  
2018 ◽  
Vol 53 (3) ◽  
pp. 424-428 ◽  
Author(s):  
Alan Gray
Keyword(s):  
Plant Species ◽  
Plant Traits ◽  
Red List ◽  
Critically Endangered ◽  
Anthropogenic Factors ◽  
Extinction Rate ◽  
Background Rate ◽  
Extinction Rates ◽  
Sixth Mass Extinction ◽  
Plant Extinction

AbstractAlthough there is increasing evidence for a sixth mass extinction, relatively few plants have been officially declared extinct (<150 are categorized as Extinct on the IUCN Red List). The Red List, although the data are neither perfect nor comprehensive, is perhaps the most reliable indicator of extinction and extinction threat. Here, data collated from the Red List, of Extinct plant species and of Critically Endangered plant species with populations in decline, are examined to address three questions: (1) How do background, continental, and island plant extinction rates compare? (2) Are biological and physical island parameters associated with plant extinction? (3) Are any plant traits associated with extinction and if so do these differ between islands and continents? The background rate for plant extinction is estimated to be 0.05–0.13 E/MSY (extinctions per million species-years) and the Red List data are above these background rates and also above a higher extinction rate of 0.15 E/MSY. The data indicate that plant extinctions are dominated by insular species. The Red List extinction data are associated with lower competitive ability and lower climate change velocities, and anthropogenic factors. Analyses using only Critically Endangered species whose populations are in decline (arguably the species most at risk of extinction in the near future) largely mirrors this pattern and suggests that drivers of plant extinction may have an inertia that could last well into the future.

Diversity dynamics of Early Jurassic ostracods of the Cordillera Ibérica (Spain) and the re-evaluation of the Pliensbachian–Toarcian mass extinction

2007 ◽  
Vol 44 (10) ◽  
pp. 1397-1411 ◽  
Author(s):  
Carmen Arias
Keyword(s):  
Mass Extinction ◽  
Environmental Changes ◽  
Marine Invertebrates ◽  
Marine Species ◽  
Extinction Time ◽  
Extinction Rate ◽  
Extinction Rates ◽  
Cordillera Ibérica ◽  
Global Extinction ◽  
Ultimate Cause

The extinction and recovery of Ostracoda at the Pliensbachian–Toarcian (P–T) boundary are analyzed based on a database of taxonomically revised Pliensbachian to Toarcian transition ostracod assemblages. In contrast to earlier assertions, the results of this study indicate that ostracod extinction rates were significant in comparison with other marine invertebrates. An extinction rate of 54% has been calculated for upper Pliensbachian ostracod species occurring in more than one section. Diversification took place in the latest Pliensbachian (Spinatum Zone) and early Toarcian (Tenuicostatum Zone), whereas diversity decrease occurred in the middle early Toarcian (Strangewaysi Subzone, Serpentinus Zone). This notable diversity decline in the early Toarcian corresponds to a global mass extinction time, whose peak has been documented in the Tenuicostatum Zone. Meanwhile, the ostracod mass extinction occurred within the Serpentinus Zone and was followed by radiation and recovery in the succeeding Bifrons Zone. Similar diversity changes of ostracods are observed in other European areas, although in the Cordillera Ibérica, the demise began later. Many aspects of this event are still debated, and there is no common cause or single set of climatic or environmental changes common to this event. The supposed extinction-causing environmental changes resulting from anoxia episodes are unclear and are unlikely to have been of sufficient intensity or geographic extent to cause this global extinction. In this paper, the decrease in marine species diversity is explained by a new palaeoceanographic scenario, in which a rapid global cooling episode is regarded as the ultimate cause.

Detection of critically endangered marine species with dwindling populations in the wild using eDNA gives hope for sawfishes

2021 ◽  
Vol 168 (5) ◽  
Author(s):  
Ramón Bonfil ◽  
Paola Palacios-Barreto ◽  
Oscar Uriel Mendoza Vargas ◽  
Melina Ricaño-Soriano ◽  
Píndaro Díaz-Jaimes
Keyword(s):  
Marine Species ◽  
Critically Endangered ◽  
In The Wild

scholarly journals Current extinction rate in European freshwater gastropods greatly exceeds that of the late Cretaceous mass extinction

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Thomas A. Neubauer ◽  
Torsten Hauffe ◽  
Daniele Silvestro ◽  
Jens Schauer ◽  
Dietrich Kadolsky ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Recovery Period ◽  
Freshwater Ecosystems ◽  
Extinction Rate ◽  
Freshwater Gastropods ◽  
Extinction Rates ◽  
Freshwater Biota ◽  
Order Of Magnitude ◽  
To Come ◽  
Mass Extinction Event

AbstractThe Cretaceous–Paleogene mass extinction event 66 million years ago eradicated three quarters of marine and terrestrial species globally. However, previous studies based on vertebrates suggest that freshwater biota were much less affected. Here we assemble a time series of European freshwater gastropod species occurrences and inferred extinction rates covering the past 200 million years. We find that extinction rates increased by more than one order of magnitude during the Cretaceous–Paleogene mass extinction, which resulted in the extinction of 92.5% of all species. The extinction phase lasted 5.4 million years and was followed by a recovery period of 6.9 million years. However, present extinction rates in European freshwater gastropods are three orders of magnitude higher than even these revised estimates for the Cretaceous–Paleogene mass extinction. Our results indicate that, unless substantial conservation effort is directed to freshwater ecosystems, the present extinction crisis will have a severe impact to freshwater biota for millions of years to come.

scholarly journals Dinosaurs in decline tens of millions of years before their final extinction

2016 ◽  
Vol 113 (18) ◽  
pp. 5036-5040 ◽  
Author(s):  
Manabu Sakamoto ◽  
Michael J. Benton ◽  
Chris Venditti
Keyword(s):  
Mass Extinction ◽  
Marked Reduction ◽  
Evolutionary Dynamics ◽  
General Pattern ◽  
Extinction Rate ◽  
Catastrophic Event ◽  
Extinction Event ◽  
Mass Extinction Event ◽  
First Time

Whether dinosaurs were in a long-term decline or whether they were reigning strong right up to their final disappearance at the Cretaceous–Paleogene (K-Pg) mass extinction event 66 Mya has been debated for decades with no clear resolution. The dispute has continued unresolved because of a lack of statistical rigor and appropriate evolutionary framework. Here, for the first time to our knowledge, we apply a Bayesian phylogenetic approach to model the evolutionary dynamics of speciation and extinction through time in Mesozoic dinosaurs, properly taking account of previously ignored statistical violations. We find overwhelming support for a long-term decline across all dinosaurs and within all three dinosaurian subclades (Ornithischia, Sauropodomorpha, and Theropoda), where speciation rate slowed down through time and was ultimately exceeded by extinction rate tens of millions of years before the K-Pg boundary. The only exceptions to this general pattern are the morphologically specialized herbivores, the Hadrosauriformes and Ceratopsidae, which show rapid species proliferations throughout the Late Cretaceous instead. Our results highlight that, despite some heterogeneity in speciation dynamics, dinosaurs showed a marked reduction in their ability to replace extinct species with new ones, making them vulnerable to extinction and unable to respond quickly to and recover from the final catastrophic event.

A Comparison of Transmitter and Synephrine on Luminescence Induction in the Firefly Larva

1972 ◽  
Vol 57 (3) ◽  
pp. 737-743
Author(s):  
ALBERT D. CARLSON
Keyword(s):  
Monoamine Oxidase ◽  
Extinction Rate ◽  
Pharmacological Effects ◽  
Response Latencies ◽  
Atp Production ◽  
Two Agents ◽  
Oxidase Enzyme ◽  
The Difference

1. The pharmacological effects of neural transmitter and synephrine are compared with respect to induction of luminescence in extirpated larval firefly lanterns. 2. Transmitter and synephrine show many similarities of action. They are as follows: (a) They both act directly on the lantern. (b) Their response latencies are relatively constant. (c) Both stimulate ATP production. (d) Neither induces a persistent intermediate in anoxic lanterns. (e) No monoamine oxidase enzyme appears to act on them. (f) The luminescence-inducing action of both is rapidly blocked by chlorpromazine. (g) They show identical responses in the presence of dichloroisoproterenol. 3. Luminescence induced by transmitter is much more rapidly extinguished than that induced by syneprine. 4. The possible reasons for the difference in luminescence extinction rate between the two agents are discussed and their different modes of delivery are emphasized.

scholarly journals Decoupled taxonomic and ecological recoveries from the Permo-Triassic extinction

2018 ◽  
Vol 4 (10) ◽  
pp. eaat5091 ◽  
Author(s):  
Haijun Song ◽  
Paul B. Wignall ◽  
Alexander M. Dunhill
Keyword(s):  
Time Scales ◽  
Carrying Capacity ◽  
Mass Extinction ◽  
Marine Species ◽  
Taxonomic Diversity ◽  
Marine Ecosystems ◽  
Trophic Levels ◽  
Ecosystem Structure ◽  
Top Down ◽  
Structure Building

The Permian-Triassic mass extinction was the worst crisis faced by life; it killed >90% of marine species in less than 0.1 million years (Ma). However, knowledge of its macroecological impact over prolonged time scales is limited. We show that marine ecosystems dominated by non-motile animals shifted to ones dominated by nektonic groups after the extinction. In Triassic oceans, animals at high trophic levels recovered faster than those at lower levels. The top-down rebuilding of marine ecosystems was still underway in the latest Triassic, ~50 Ma after the extinction, and contrasts with the ~5-Ma recovery required for taxonomic diversity. The decoupling between taxonomic and ecological recoveries suggests that a process of vacant niche filling before reaching the maximum environmental carrying capacity is independent of ecosystem structure building.

scholarly journals Haiti’s biodiversity threatened by nearly complete loss of primary forest

2018 ◽  
Vol 115 (46) ◽  
pp. 11850-11855 ◽  
Author(s):  
S. Blair Hedges ◽  
Warren B. Cohen ◽  
Joel Timyan ◽  
Zhiqiang Yang
Keyword(s):  
Tropical Forests ◽  
National Parks ◽  
Mass Extinction ◽  
Forest Cover ◽  
Secondary Growth ◽  
Complete Loss ◽  
Primary Forest ◽  
The Difference ◽  
Primary Forests ◽  
Agricultural Organization

Tropical forests hold most of Earth’s biodiversity. Their continued loss through deforestation and agriculture is the main threat to species globally, more than disease, invasive species, and climate change. However, not all tropical forests have the same ability to sustain biodiversity. Those that have been disturbed by humans, including forests previously cleared and regrown (secondary growth), have lower levels of species richness compared with undisturbed (primary) forests. The difference is even greater considering extinctions that will later emanate from the disturbance (extinction debt). Here, we find that Haiti has less than 1% of its original primary forest and is therefore among the most deforested countries. Primary forest has declined over three decades inside national parks, and 42 of the 50 highest and largest mountains have lost all primary forest. Our surveys of vertebrate diversity (especially amphibians and reptiles) on mountaintops indicates that endemic species have been lost along with the loss of forest. At the current rate, Haiti will lose essentially all of its primary forest during the next two decades and is already undergoing a mass extinction of its biodiversity because of deforestation. These findings point to the need, in general, for better reporting of forest cover data of relevance to biodiversity, instead of “total forest” as defined by the United Nation’s Food and Agricultural Organization. Expanded detection and monitoring of primary forest globally will improve the efficiency of conservation measures, inside and outside of protected areas.

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