Archives de catégorie : Biodiversity

A Curious Paleo Puzzle

by W. Eschenbach, Feb 23, 2024 in WUWT


 

A final possibility, of course, is that the warming has little to do with CO2 and that the CO2 levels are a function of temperature and not the other way around …

I titled this post “A Curious Paleo Puzzle”. That’s the puzzle. How can an increase of 13 W/m2 in CO2 forcing cause an increase of 115 W/m2 of upwelling surface longwave radiation?

All suggestions welcome.

 

….

Claim: Computer Models Predict a Third of Vertebrates will Die by 2100

by E. Worrall, Dec 17, 2022 in WUWT


 

My question – which part of this real world story of ecological disaster and recovery shouts fragile food web?

In my opinion the European supercomputer food web experiment is way too unrealistic to draw real world conclusions. New connections in the real world food web appear all the time, no food resource remains underutilised for long, even when the underutilised resource is a deadly toxic toad. Any breaks in the food web caused by climate change or disease or whatever, in the real world are rapidly filled.

There are a handful of species which are so specialised they actually would die if their food source was removed. For example, Koala Bears are so specialised at eating Eucalyptus leaves, they would likely all die if say a Eucalypt version of Dutch Elm Disease killed off all the Eucalyptus trees.

But are 17.6% of vertebrate species so specialised they cannot adapt to a small change in temperature? Are 27% of vertebrates about to die out? That seems highly implausible.

A few degrees of warming, if it occurs, is not an asteroid scale ecological catastrophe, or a million year duration volcanic eruption, it is a mild shift in climatic conditions, which life will have no problem adapting to if the paleo record is any guide. Just like life has already adapted to the many climatic shifts, introduced species and other disruptions which have occurred in Earth’s geological past.

Chicken Little Propaganda Dressed Up As Science

by P.  Ridd, Nov 26, 2022 in InstitueofPublicAffairs


ORIGINALLY APPEARED IN THE AUSTRALIAN

The Bureau of Meteorology and the CSIRO have delivered their ­biennial dose of depression about the climate, but their report ignores a slew of positive environmental changes.

The Bureau of Meteorology and the CSIRO have delivered their ­biennial dose of depression about the climate in their latest State of the Climate report. The climate has warmed by 1.5C and there is barely a single benefit – it is all ­disaster.

It is often said, “if it is too good to be true, it probably is” and you are being conned. What about too bad to be true? Can a gently warming climate have no significant benefits at all? The only marginally encouraging part of the report is about northern Australia. There might have been a slight reduction in cyclone numbers, and there has been a bit more rain in the recent decades.

Apart from that, the report reads like the Book of Exodus – one disaster after another. Only the frogs and boils are missing.

But it is significant that the period when Egyptians were building pyramids, which was hotter than today’s climate, is often called the Holocene Climatic Optimum. The word “optimum” was an indication that scientists working in the era before climate alarmism could see some advantage of a warmer climate.

A sure sign that the report tries too hard to find disaster is when it discusses coral bleaching and the Great Barrier Reef. It stresses that there have been four bleaching events in the past six years, which it implies were devastating. But for some reason the report fails to mention that this year the reef recorded its highest amount of coral since records began in 1985.

This proves that all the hype about the coral loss from bleaching was greatly exaggerated. But the report writers were obviously ­untroubled by the contradictory evidence. They ignored it.

CNN Pushes Coral Apocalypse As Great Barrier Reef Shows Record Growth

by H.S. Sterling, Aug 5, 2022 in ClimateChangeDispatch


A new report from the Australian Institute of Marine Science (AIMS) shows the Great Barrier Reef (GBR) set new records for extent this year.

Sadly, in a story titled “Parts of Great Barrier Reef record highest amount of coral in 36 years,” CNN tried to turn this good news contained in the headline into a climate cautionary tale. [bold, links added]

According to the AIMS annual report, the northern and central regions of the 2,300 km GBR ecosystem have the most coral since the surveys began 36 years ago.

As CNN notes, an AIMS survey of 87 sections of the GBR found that between August 2021 and May 2022, average hard coral cover in the upper region and central areas of the reef increased by around one-third.

AIMS CEO Dr. Paul Hardisty told CNN that the report shows the GBR can “recover from mass bleaching and outbreaks of crown-of-thorns starfish that feed on coral.”

One could be forgiven for missing this good news since CNN spent just a few paragraphs discussing the GBR’s expansion.

More than two-thirds of CNN’s story talked about the threat posed to the GBR from recent bleaching events purportedly driven by climate change.

CNN’s story largely ignored the fact that most of the GBR’s coral colonies impacted by bleaching had recovered, as the AIMS report documents.

In a press release from the Global Warming Policy Foundation (GWPF) commenting on the AIMS report its director, Benny Peiser, Ph.D., said, “This is just the latest example of empirical data making a mockery of the catastrophists. For how much longer do they think they can get away with it?”

The GWPF recently released a study discussing the positive health of coral reefs in general, by Peter Ridd, Ph.D., a long-time researcher on the GBR and coral reefs.

..;

Official data confirms reef in rude good heath

by P. Homewood, Aug 4 , 2022 in NotaLotofPeopleKnowThat


Official data released today reveals that Australia’s Great Barrier Reef is in excellent health, with coral cover reaching record levels for the second consecutive year.

The increase will be surprising to members of the public, who are regularly hit with scare stories about coral bleaching and false tales about a reef in long-term decline.

A new note, published today by the Global Warming Policy Foundation, explains that the data shows clearly how a handful of coral bleaching events that have affected the reef since 2016 have had very limited impact on overall coral cover.

Evolution after Chicxulub asteroid impact: Rapid response of life to end-cretaceous mass

by Geological Society of America, July 14, 2020 in ScienceDaily


The impact event that formed the Chicxulub crater (Yucatán Peninsula, México) caused the extinction of 75% of species on Earth 66 million years ago, including non-avian dinosaurs. One place that did not experience much extinction was the deep, as organisms living in the abyss made it through the mass extinction event with just some changes to community structure.

New evidence from International Ocean Discovery Program (IODP) Expedition 364 of trace fossils of burrowing organisms that lived in the seafloor of the Chicxulub Crater beginning a few years after the impact shows just how quick the recovery of the seafloor ecosystem was, with the establishment of a well-developed tiered community within  approximately 700,000 years after the event.

Renewable energy development threatens many globally important biodiversity areas

by Rehbein J.A. et al., March 2020, in GlobalChangeBiology


Transitioning from fossil fuels to renewable energy is fundamental for halting anthropogenic climate change. However, renewable energy facilities can be land‐use intensive and impact conservation areas, and little attention has been given to whether the aggregated effect of energy transitions poses a substantial threat to global biodiversity. Here, we assess the extent of current and likely future renewable energy infrastructure associated with onshore wind, hydropower and solar photovoltaic generation, within three important conservation areas: protected areas, Key Biodiversity Areas and Earth’s remaining wilderness. We identified 2,206 fully operational renewable energy facilities within the boundaries of these conservation areas, with another 922 facilities under development. Combined, these facilities span and are degrading 886 protected areas, 749 Key Biodiversity Areas, and 40 distinct wilderness areas. Two trends are particularly concerning. First, while the majority of historical overlap occurs in Western Europe, the renewable electricity facilities under development increasingly overlap with conservation areas in South East Asia, a globally important region for biodiversity. Second, this next wave of renewable energy infrastructure represents a ~30% increase in the number of protected areas and Key Biodiversity Areas impacted and could increase the number of compromised wilderness areas by ~60%. If the world continues to rapidly transition towards renewable energy these areas will face increasing pressure to allow infrastructure expansion. Coordinated planning of renewable energy expansion and biodiversity conservation is essential to avoid conflicts that compromise their r​e​s​p​e​c​t​

Actualité Débats Kervasdoué – Quelques vérités sur la biodiversité

by Jean de Kersvasdoué, 6 janvier 2020 in LePoint


Derrière une bataille de chiffres alarmistes se cachent des biais statistiques et des questions de fond sur ce que l’on entend par « biodiversité ».

 

À l’occasion des vœux à la nation, le président de la République, Emmanuel Macron, a déclaré vouloir « œuvrer en faveur de la biodiversité ». Cet objectif est noble pour de multiples raisons et, notamment, parce que certaines espèces de grands mammifères sont menacées mais aussi quelques plantes et animaux de la métropole. Les grands singes, le rhinocéros noir sont en voie d’extinction. En ce qui concerne ce dernier, selon l’UICN, il n’en restait que 5 055 têtes en 2012. Or ces animaux continuent d’être chassés pour les prétendues valeurs aphrodisiaques de leur corne revendue 40 000 dollars le kilo à Shanghai. On comprend pourquoi les braconniers les recherchent et trouvent des complicités chez des gardes mal payés qui, en outre, risquent leur vie en s’opposant aux auteurs de ces regrettables massacres. A contrario, certaines espèces que l’on croyait disparues à l’état sauvage renaissent, comme la perruche de l’île Maurice ou l’oryx d’Arabie. Toutefois, en la matière, les bonnes nouvelles sont rares et la liste des espèces menacées à l’état sauvage s’allonge dans le monde du fait de la croissance de la population de la planète et de la mise en culture d’espaces jusque-là occupés par la forêt. Des écosystèmes disparaissent et avec eux végétaux et animaux qui y vivaient. Si donc préserver ces espèces est un objectif louable, il concerne rarement la France à l’exception des forêts de Guyane, mais il la touche cependant.

En France métropolitaine, le nombre de plantes supérieures, à fleurs, dites « phanérogames », donc hors champignons, mousses, fougères, lichens, algues, etc., du territoire métropolitain est d’environ 5 000 espèces sauvages ou cultivées. Pour les vertébrés, on y trouve de l’ordre de 40 poissons d’eau douce, 40 amphibiens (ou batraciens), 40 reptiles (serpents, lézards, tortues), 400 oiseaux en comptant des migrateurs qui ne nichent pas sur le territoire national, et 80 mammifères. Au total : environ 600 vertébrés. Donc, en additionnant les végétaux supérieurs et les animaux supérieurs, au sens de l’évolution darwinienne, 5 600 espèces en France. La très grande majorité n’est pas menacée et les espèces qui sont prétendues l’être (1) ne le sont pas toujours.

L’exagération est la règle

Sur les six espèces décrites comme pouvant disparaître, il y a une plante (l’orchis couleur de lait) et cinq animaux (la sterne de l’Arctique, le lynx boréal, la grenouille des champs, la tortue d’Hermann et l’anguille). On trouve l’orchis couleur de lait dans le sud de la France et en Corse, il est difficile de mesurer la réalité de la menace qui pèse sur elle (2), faute de méthode de recensement. En ce qui concerne les espèces animales, deux ne sont en rien menacées (la sterne et le lynx boréal). Si la grenouille des champs l’est dans notre pays, elle ne l’est pas ailleurs en Europe à l’exception de la grenouille des Pyrénées. Restent la tortue d’Hermann et l’anguille européenne.

La tortue d’Hermann est la seule espèce de tortue terrestre de France. Elle est présente dans le Var et en Corse. Son habitat est détruit par les feux de forêt, le débroussaillage, le morcellement des parcelles, les routes et l’habitat pavillonnaire. Quant à l’anguille européenne (Anguilla anguilla), autrefois abondante dans tous les cours d’eau et les zones humides (lacs, étangs, marais, mares, fossés), son déclin se constate depuis 40 ans. Cette régression provient de plusieurs facteurs : divers contaminants toxiques (pesticides organochlorés bio-accumulés par l’anguille), la surpêche des civelles et des adultes de plus en plus appréciés, le braconnage, les obstacles sur la route des alevins et une augmentation du taux de parasitisme (par le nématode Anguillicola crassus) qui perturbe la migration marine des adultes. Un règlement européen (R(CE) no 1100/2007) impose des mesures de connaissance et de protection et de gestion de l’anguille et semble porter des fruits.

Continuer la lecture de Actualité Débats Kervasdoué – Quelques vérités sur la biodiversité

Celebrating America’s Environmental Stewardship

by Jim Steele, July 10, 209 in WUWT


What’s Natural?

Celebrating America’s Environmental Stewardship

I resent the one-sided mis-characterization of humanity as “destroyers of our environment”. Humans certainly had negative impacts on most ecosystems. However, in contrast to a recent United Nations report insinuating we are threatening one million species with extinction, humans have been working hard to restore nature and prevent further extinctions. Most endangered species are still staggering from disruptions initiated centuries ago. But now humans are correcting past mistakes.

Islands have been extinction hotspots. Sixty-one percent of all known extinctions have occurred on islands and 37% of today’s critically endangered species are found only on islands. The main driver of island extinctions has been purposeful or unintentional introductions of alien species. Introduced species are implicated in 81% of all island extinctions. With no natural predators, Island species did not evolve needed behaviors to avoid introduced rats, cats and stoats. Researchers now suggest eradication of rats and other introduced mammals could prevent the extinction of up to 75% of threatened island birds, reptiles and mammals.

 

 

Will Climate Change Drive a Million Species Extinct?

by Vijay Jayaraj, June 3, 2019 Townhall


A million species threatened by “climate change”? Well, climate change as defined by the UN Framework Convention on Climate Change (“a change of climate that is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and that is in addition to natural climate variability observed over comparable time periods”) isn’t likely to bring about any warming exceeding that of the warm periods mentioned above.

Which of course means it’s not likely to drive millions of species extinct. In fact, it will be a miracle if the gradual change in climate causes any alarming extinctions at all.

Only illegal hunting and habitat destruction (despite protection by governments) continue to threaten endangered species. Even in the worst case, they won’t cause species extinctions in the millions.

Vijay Jayaraj (M.Sc., Environmental Science, University of East Anglia, England), Research Associate for Developing Countries for the Cornwall Alliance for the Stewardship of Creation, lives in Bangalore, India.

Patrick Moore auditionné par la Chambre des représentant des Etats Unis à propos du rapport de l’IPBES

by Usbek, 29 mai 2019 in ClimatEnvironnementEnergie


Le  22 mai 2019 la Chambre des représentants des Etats Unis a organisé une audition sur le récent rapport d’évaluationglobale de l’IPBES (Plateforme intergouvernementale scientifique et politique sur la biodiversité et les services éco systémiques ).

Patrick Moore a été invité a donner son témoignage; nous en donnons ci-dessous une traduction (les liens et renvois en bas de page sont du traducteur).


Je vous remercie de m’avoir donné l’occasion de témoigner à l’audience d’aujourd’hui.

En 1971, alors que j’étais doctorant en écologie, je me suis joint à un groupe d’activistes dans un sous-sol d’église à Vancouver, au Canada, et j’ai traversé le Pacifique à bord d’un petit bateau pour protester contre les essais américains de bombes à hydrogène en Alaska. Nous sommes devenus Greenpeace. Après 15 ans au sein du comité directeur, j’ai dû quitter Greenpeace, qui commençait à adopter des politiques que je ne pouvais accepter d’un point de vue scientifique.

Je me suis donné comme mission de toujours appliquer de sains principes scientifiques lors de l’examen des problèmes environnementaux critiques auxquels nous sommes confrontés aujourd’hui.

Ce n’est qu’au début des années 1900, marquées par la disparition définitive de la tourte voyageuse en 1914, que le grand public a commencé à s’intéresser de près à la question de l’extinction des espèces. Cette prise de conscience a été inspirée par l’activisme précoce de Théodore Roosevelt, John Muir et Gifford Pinchot.

Hearing on the Biodiversity Report

by Judith Curry, May 22, 2019 in ClimateEtc.


The House Natural Resources Committee Subcommittee on Water, Oceans and Wildlife is holding a Hearing today on Responding to the Global Assessment Report of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services.

The link to the Hearing page is here [link].

Based on my previous experience with this Committee, the written testimonies will not be posted, and the Hearing will live stream on their Facebook page [link]

Here is the list of witnesses:

  • Sir Robert Watson, Immediate Past Chair IPBES
  • Dr. Eduardo S. Brondizio, Co-Chair IPBES Global Assessment 
  • Dr. Yunne Shin, Coordinating Lead Author, IPBES Global Assessment
  • Dr. Patrick Moore, Chairman CO2 Coalition [link to written testimony Moore]
  • Mr. Marc Morano, Founder Climate Depot [link to written testimony Morano]
  • Dr. Jacob Malcolm,  Director Center for Conservation Innovation, Defenders of Wildlife

Quite an interesting list.  Clearly some of the leading honchos for the IPBES Report.  Surprised that the Republicans apparently got to pick several witnesses.

Having Marc Morano on this list is like waving a red cape before a bull.  True to form, Marc has prepared an extremely hard hitting report for his written testimony, which was sent to me (and others) via email.  Excerpts from Morano’s testimony are provided below:

Recent Studies Indicate Species Extinctions Decline With Warming – Mass Extinction Events Due To COOLING

by K. Richard, May 16, 2019 in NoTricksZone


In the past it has been widely reported that high and abruptly changing CO2 concentrations led to climate conditions that were “too hot for complex life to survive” on the planet.
More recently, though, scientists have determined that the opposite may have been true: mass extinction events occurred during periods of global cooling, expansive ice sheet growth, and marine-habitat-destroying sea level drops of more than 100 meters.
In fact, of the 5 previous mass extinctions, volcanism-induced glaciation is thought to be responsible for the 1st, 3rd, and 4th events, with the 2nd unknown and the 5th from an aseteroid impact.  None of these explanations have ties to CO2 concentrations or sudden warming.

Image Sources: Loehle & Eschenbach (2012), BBC, Wrightstone, 2019

UN Biodiversity Officials Fail Transparency Test

by Donna Laframboise, May 13, 2019 in BigPictureNews


The United Nations Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) is a clone of the IPCC, the UN’s climate body. But there are some notable differences.

We’re told that a great deal of power resides with the Multidisciplinary Expert Panel (MEP), which currently consists of 28 individuals. These are the people who, for example, decide which international scholars will be assigned to discuss which topics within the pages of official IPBES reports.

To its credit, that entity’s website has been designed to provide the CV of everyone who sits on this panel. Rather than taking the UN’s word for it that these are world class experts, the public is given the opportunity to examine their credentials firsthand.

But saying you believe in transparency is different from acting like it. If organizations aren’t living up to the standards they’ve set for themselves, that’s worth noticing.

Last week was hugely important for the IPBES – it sought and received massive international media coverage. Despite this, it utterly failed its own transparency test. The CVs of most MEP members aren’t actually available online.

The UN’s Extinction Warning Doesn’t Add Up (Except On The BBC)

by Toby Young, May 9, 2019 in ClimateChangeDispatch


Anyone watching the BBC’s News at Ten on Monday would have been surprised to learn that economic growth poses a dire threat to the future of life on this planet.

We’re used to hearing this from climate change campaigners, but I’ve always taken such claims with a pinch of salt, suspecting that the anti-capitalist left is distorting the evidence. Apparently not.

‘One million species at risk of imminent extinction according to a major UN report,’ intoned the BBC. ‘It says the Earth’s ecosystems are being destroyed by the relentless pursuit of economic growth.’

So does this mean the Extinction Rebellion protestors are right?

I decided to do some digging to see if one million species really do ‘face extinction in the next few decades’, as the BBC put it.

That claim is based on a report by the UN’s Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), but it hasn’t been published yet.

Nature crisis: Humans ‘threaten 1m species with extinction’-BBC

by P. Homewood, May 7, 2019 in NotaLotofPeopleKnowThat


The BBC has just reported on the newly published Summary for Policy Makers of the as yet unpublished UN 1800 page global assessment of nature compiled by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). The two day old ‘climate crisis’, so recently [not] declared by the British government has already been knocked off the top spot as far as existential crises are concerned and is now officially languishing in 3rd place, in the Second Division. Land use change is now Premier Division. However, unlike action on the ‘climate crisis’, which has become a $1.5 trillion industry, action on land use change has been negligible to non-existent. Even hunting (legal and non-legal) and the direct exploitation of wildlife is one division above climate change in terms of the threat to biodiversity. Bugger all has been done to address these threats too, relatively speaking, during the last three decades, whereas trillions has been thrown at ineffective, and socially, economically and environmentally damaging attempts to limit global warming to 2C (and latterly 1.5C). I warned about this 3 years ago.

IPCC Clone Predicts Doom

by Donna Laframboise, May 6, 2019 in BigPictureNews


Here we ago again. For some time, I’ve warned that the Intergovernmental Panel on Climate Change (IPCC) is a template, that the United Nations is up to the same tricks elsewhere.

Today, in Paris, an IPCC clone known as the IPBES – the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services – will announce the completion of an 1,800-page report.

Jonathan Watts, the UK Guardian‘s global environment editor, has already told us everything we need to know about this ‘IPCC for Nature‘.

Under the headline Biodiversity crisis is about to put humanity at risk, UN scientists to warn, he insists this report was written by “The world’s leading scientists.” Funny, that’s how compliant, gullible journalists described IPCC personnel. For years and years. Until I began to notice that some of those involved were graduate students in their 20s.

WHAT? NO SIXTH EXTINCTION?

by Andrew Montford, April 23, 2019 in GWPF


Extinction Rebellion seem to be everywhere at the moment. And everywhere their story is the same. We are in the middle of a climate catastrophe. As the Huffington Post put it,

Human-caused climate change is driving sea-level rise, drought, extreme weather and a biodiversity crisis that scientists have declared Earth’s sixth mass extinction event. As many as 150 species die off each day.

Scary eh? Surely that’s enough to justify the odd street protest?

It was therefore interesting to see read some remarks from Richard Betts today. Professor Betts is the head of climate impacts at the Met Office, so his views in this area carry a certain amount of weight. Asked what he thought were the top three negative impacts of climate change that have “absolutely started”, he replied:

  • Sea level rise
  • Increasing risk of high temperatures
  • Changes in phenology and distribution for numerous species

This left me agog. There was nothing about drought or hurricanes or any of the other manifestations of extreme weather that are said to be afflicting us; nothing about floods, or typhoons, or desertification or crashing crop yields or climate refugees, mass extinctions, skydiving walruses and any of the thousand and one tall tales that climate activists spin and the media faithfully repeat every day. The contrast between this take on currently observed negative impacts and David Attenborough’s risible Climate Change: the Facts programme last week is startling. The take home message is that most of what the “national treasure” told viewers about climate change was grubby insinuation rather than fact: less to do with science than with the BBC’s ongoing eco-campaign.

“Global climate change” does not cause species extinctions

by Paul Berth, March 22, 2019 in ScienceClimatEnergie


Contrary to what the media tries to make you believe, global climate change is not a major cause of species extinction. A recent study published in March 2019 in Frontiers in Ecology and the Environment shows that the major cause of extinction is the introduction of invasive alien species (IAS) into ecosystems. This phenomenon, well known to biologists and confirmed by the IUCN (International Union for the Conservation of Nature), is unfortunately little known to the general public.

Figure 1. Number of recent animal extinctions (IUCN categories “extinct” [EX] and “extinct in the wild” [EW]) for different groups of animals (figures from IUCN Table 3a). The colors provide information on the causes of the extinctions (“Driver”); for example dark purple is used for IAS (“Alien”), extinctions caused by local species (“Native”) are light purple. The category “Neither” includes other causes of extinction or unknown causes (source, Blackburn et al., 2019).

 

 

Le “Changement climatique global’ ne cause pas de disparitions d’espèces

by Prof. Paul Berth, 22 mars 2019 in ScienceClimateEnergie


Contrairement à ce que les médias tentent de vous faire croire, le changement climatique global n’est pas une cause majeure de disparition d’espèces. Une récente étude publiée en mars 2019 dans le journal Frontiers in Ecology and the Environment vous le démontre : la cause majeure d’extinction est l’introduction d’espèces exotiques envahissantes (EEE) dans les écosystèmes. Ce phénomène, bien connu des biologistes et confirmé par l’IUCN(Union Internationale pour la Conservation de la Nature), est malheureusement peu connu du grand public.

1. Introduction

En se déplaçant d’un continent à l’autre, l’être humain a toujours emmené avec lui toute une série de plantes et d’animaux qui se retrouvaient ainsi en dehors de leurs limites biogéographiques habituelles. Avec le développement du commerce international ce phénomène ne fait que s’amplifier. Par exemple, à l’intérieur de l’Union Européenne, le nombre d’EEE aurait augmenté de 76% entre 1970 et 2007. Bien que l’impact écologique de la plupart des espèces introduites est inconnu ou semble négligeable, il est démontré que certaines introductions d’espèces ont provoqué des changements substantiels dans des écosystèmes[1]. Ces changements incluent souvent la disparition d’espèces locales[2]. On a d’abord pensé que ces phénomènes d’extinction étaient exagérés et que des espèces locales pouvaient également être à la base d’extinctions[3], et certains auteurs pensent même que les efforts déployés pour contrôler ou éradiquer les espèces étrangères introduites ne seraient pas nécessaires[4]. Cependant, personne n’a jamais vraiment testé si les espèces introduites provoquaient plus ou moins d’extinctions par rapport aux espèces locales ou aux autres causes d’extinctions. Cette question a donc été étudiée par l’équipe de Tim Blackburn (University College London, UK) dans une récente publication de mars 2019[5]. Ils ont pour cela utilisé la base de données des extinctions globales fournie par l’IUCN.

Figure 1. Nombre d’extinctions animales récentes (catégories IUCN “extinct” [EX] et “extinct in the wild” [EW]) pour différents groupes d’animaux (chiffres issus de la Table 3a de l’IUCN). Les couleurs renseignent sur les causes des extinctions (“Driver”); par exemple le mauve foncé est employé pour les EEE (“Alien”), les extinctions causées par des espèces locales (“Native”) sont en mauve clair. La catégorie “Neither” comporte les autres causes d’extinction ou alors des causes inconnues (source, Blackburn et al. 2019).

 

Global Warming off the hook? Alien species are primary cause of recent global extinctions

by University College London, March 3, 2019 in WUWT


Alien species are the main driver of recent extinctions in both animals and plants, according to a new study by UCL researchers.

They found that since 1500, alien species have been solely responsible for 126 extinctions, 13% of the total number studied.

Of 953 global extinctions, 300 happened in some part because of alien species, and of those 300, 42% had alien species alone listed as the cause of their demise.

The study, published today in Frontiers in Ecology and the Environment, used data from the 2017 IUCN Red List on the total numbers of species that are considered to have gone extinct globally since 1500.

In total, 261 out of 782 animal species (33.4%) and 39 out of 153 plant species (25.5%) listed aliens as one of their extinction drivers. In contrast, native species impacts were associated with only 2.7% of animal extinctions and 4.6% of plant extinctions.