Écologie, extinctions…

1. Mégafaune et biomasse aujourd’hui
2. Déclin des insectes et petits animaux aujourd’hui
3. Extinctions et déclins de mégafaune depuis le pliocène
4. Impact de la chasse aux trophées
5. Sujets d’écologie divers

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An inconvenient misconception: Climate change is not the principal driver of biodiversity loss [Texte]
Caro et al.
Conservation letters, 2022.

Mégafaune et biomasse aujourd’hui

Mammal population densities at a global scale are higher in human‐modified areas
Tucker et al.
Ecography, 2020
https://onlinelibrary.wiley.com/doi/10.1111/ecog.05126

Our results indicate shifts in mammal population densities in human modified landscapes, which is due to the combined effect of species filtering, increased resources and a possible reduction in competition and predation. Our study provides further evidence that macroecological patterns are being altered by human activities, where some species will benefit from these activities, while others will be negatively impacted or even extirpated.

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Mammal species composition reveals new insights into Earth’s remaining wilderness
Belote et al.
Frontiers in ecology and the environment, 2020
https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/fee.2192?casa_token=z09OYeaorbYAAAAA%3ASipPR-bBOEIxwg6XkoLqFSjvq_-GTbm9VD18vpGs7D4Yp3oAnWEHKsef5p2Gchx9nEo3JKOrbUOURQo

Contrary to our expectations, we found that the global human footprint was not strongly correlated with mammal community intactness and uncovered surprising situations where both the human footprint and mammal species intactness were high, and other examples where both were low.

Mammal intactness belote et al 2020

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Clustered versus catastrophic global vertebrate declines
Leung et al.
Nature, 2020
https://www.nature.com/articles/s41586-020-2920-6

previous analyses have estimated a mean vertebrate decline of more than 50% since 1970 (Living Planet Index²). Here we show, however, that this estimate is driven by less than 3% of vertebrate populations; if these extremely declining populations are excluded, the global trend switches to an increase.
[…] We show that, of taxonomic–geographic systems in the Living Planet Index, 16 systems contain clusters of extreme decline (comprising around 1% of populations; these extreme declines occur disproportionately in larger animals) and 7 contain extreme increases (around 0.4% of populations). The remaining 98.6% of populations across all systems showed no mean global trend. However, when analysed separately, three systems were declining strongly with high certainty (all in the Indo-Pacific region) and seven were declining strongly but with less certainty (mostly reptile and amphibian groups). Accounting for extreme clusters fundamentally alters the interpretation of global vertebrate trends and should be used to help to prioritize conservation efforts.

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Meta-analysis of multidecadal biodiversity trends in Europe
Pilotto et al.
Nature communications, 2020
https://www.nature.com/articles/s41467-020-17171-y#rightslink

Our results reveal that local trends of abundance, richness and diversity differ among biogeoregions, realms and taxonomic groups, demonstrating that biodiversity changes at local scale are often complex and cannot be easily generalized. However, we find increases in richness and abundance with increasing temperature and naturalness as well as a clear spatial pattern in changes in community composition (i.e. temporal taxonomic turnover) in most biogeoregions of Northern and Eastern Europe.

TRends biodiversity Crossley 2020

Introduced herbivores restore Late Pleistocene ecological functions
Lundgren et al.
PNAS, 2020
https://www.pnas.org/content/early/2020/03/17/1915769117

Many introduced herbivores restore trait combinations that have the capacity to influence ecosystem processes, such as wildfire and shrub expansion in drylands. Although introduced species have long been a source of contention, our findings indicate that they may, in part, restore ecological functions reflective of the past several million years before widespread human-driven extinctions.

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Are we eating the world’s megafauna to extinction?
Ripple et al.
Conservation letters, 2019
https://conbio.onlinelibrary.wiley.com/doi/full/10.1111/conl.12627

Surprisingly, direct harvesting of megafauna for human consumption of meat or body parts is the largest individual threat to each of the classes examined, and a threat for 98% (159/162) of threatened species with threat data available. Therefore, minimizing the direct killing of the world’s largest vertebrates is a priority conservation strategy that might save many of these iconic species and the functions and services they provide.

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The biomass distribution on Earth
Bar-On et al.
PNAS 2018
https://www.pnas.org/content/115/25/6506

Biomass distribution current

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Living Planet Index
WWF, 2018
https://wwf.panda.org/knowledge_hub/all_publications/living_planet_report_2018/

Living planet index

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A continent-wide assessment of the form and intensity of large mammal herbivory in Africa
Hempson et al.
Science, 2015
https://science.sciencemag.org/content/350/6264/1056

Hempson 2015 biomass to rainfall

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Collapse of the world’s largest herbivores
Ripple et al.
Science advances, 2015
https://advances.sciencemag.org/content/1/4/e1400103?con=&dom=prime&src=syndication

Large herbivores are generally facing dramatic population declines and range contractions, such that ~60% are threatened with extinction. Nearly all threatened species are in developing countries, where major threats include hunting, land-use change, and resource depression by livestock.

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Marine defaunation: Animal loss in the global ocean
McCauley et al.
Science, 2015
https://science.sciencemag.org/content/sci/347/6219/1255641.full.pdf

Three lessons emerge when comparing the marine and terrestrial defaunation experiences: (i) today’s low rates of marine extinction may be the prelude to a major extinction pulse, similar to that observed on land during the industrial revolution, as the footprint of human ocean use widens; (ii) effectively slowing ocean defaunation requires both protected areas and careful management of the intervening ocean matrix; and (iii) the terrestrial experience and current trends in ocean use suggest that habitat destruction is likely to become an increasingly dominant threat to ocean wildlife over the next 150 years.

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Defaunation in the Anthropocene
Rodolfo Dirzo et al.
Science, 2014

Cliquer pour accéder à Collen_Dirzo%20etal%202014%20Science%20Accepted.pdf

https://www.researchgate.net/publication/264247848_Defaunation_in_the_Anthropocene

Among terrestrial vertebrates 322 species have become extinct since 1500, while populations of the remaining species show 25% average decline in abundance. Invertebrate patterns are equally dire: 67% of monitored populations show 45% mean abundance decline. Such animal declines will cascade onto ecosystem functioning and human well-being. Much remains unknown about this “Anthropocene defaunation”; these knowledge gaps hinder our capacity to predict and limit defaunation impacts. Clearly, however, defaunation is both a pervasive component of the planet’s sixth mass extinction, and also a major driver of global ecological change.

Dirzo et al. 2014 Defaunation in the anthropocene

Diminution invertébrés depuis 1970

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Wildlife comeback in Europe
Deinet et al.
Rewilding Europe, 2013

Cliquer pour accéder à Wildlife-Comeback-in-Europe-the-recovery-of-selected-mammal-and-bird-species.pdf

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Harvesting the Biosphere: The Human Impact
Vaclav Smil
Population and development review, 2011

Cliquer pour accéder à PDR37-4.Smil_.pgs613-636.pdf

Smill 2011 biomass evolution

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Impacts of Biodiversity Loss on Ocean Ecosystem Services
Worm et al.
Science, 2006

Cliquer pour accéder à AR-024.pdf

Worm et al. 2006

Déclin des insectes et petits animaux aujourd’hui

Pour les insectes, nouvelle page dédiée.

Overall, changes in light conditions, in particular ALAN, significantly impacted an amphibian model in laboratory conditions. This work underscores the importance of considering not only the direct effects of light on fitness metrics but also the indirect effects of light with other abiotic and biotic stressors. Anthropogenic-induced changes to light conditions are expected to continue increasing over time so understanding the diverse consequences of shifting light conditions will be paramount to protecting wildlife populations.

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Decline of the North American avifauna*
Rosenberg et al.
Science, 2019
https://science.sciencemag.org/content/early/2019/09/18/science.aaw1313

Using multiple and independent monitoring networks, we report population losses across much of the North American avifauna over 48 years, including once common species and from most biomes. Integration of range-wide population trajectories and size estimates indicates a net loss approaching 3 billion birds, or 29% of 1970 abundance. A continent-wide weather radar network also reveals a similarly steep decline in biomass passage of migrating birds over a recent 10-year period.

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The new world atlas of artificial night sky brightness
Falchi et al.
Science advances, 2016
https://advances.sciencemag.org/content/2/6/e1600377

Artificial lights raise night sky luminance, creating the most visible effect of light pollution—artificial skyglow. Despite the increasing interest among scientists in fields such as ecology, astronomy, health care, and land-use planning, light pollution lacks a current quantification of its magnitude on a global scale. To overcome this, we present the world atlas of artificial sky luminance, computed with our light pollution propagation software using new high-resolution satellite data and new precision sky brightness measurements. This atlas shows that more than 80% of the world and more than 99% of the U.S. and European populations live under light-polluted skies. The Milky Way is hidden from more than one-third of humanity, including 60% of Europeans and nearly 80% of North Americans. Moreover, 23% of the world’s land surfaces between 75°N and 60°S, 88% of Europe, and almost half of the United States experience light-polluted nights.

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The impact of free-ranging domestic cats on wildlife of the United States
Loss et al.
Nature communication, 2013.
https://www.nature.com/articles/ncomms2380/

We estimate that free-ranging domestic cats kill 1.3–4.0 billion birds and 6.3–22.3 billion mammals annually. Un-owned cats, as opposed to owned pets, cause the majority of this mortality. Our findings suggest that free-ranging cats cause substantially greater wildlife mortality than previously thought and are likely the single greatest source of anthropogenic mortality for US birds and mammals.

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Extinctions et déclins de mégafaune depuis le pliocène

La section commençant à devenir très volumineuse, elle a gagné une page dédiée.

Impact de la chasse aux trophées

Our results suggest that in Namibia, a trophy hunting ban would be viewed very poorly by conservancy residents, and would seriously weaken their support for wildlife conservation. The imposition of trophy hunting policies by countries far from where rural land managers are conserving wildlife would not only restrict communities’ livelihood options, but may have perverse, negative impacts on wildlife conservation.

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International pressure to ban trophy hunting is increasing. However, we argue that trophy hunting can be an important conservation tool, provided it can be done in a controlled manner to benefit biodiversity conservation and local people. Where political and governance structures are adequate, trophy hunting can help address the ongoing loss of species.

Di Minin et al. [1] are correct in stating that trophy hunting can increase funding for conservation (this is well known), but they have failed to address the effects of trophy hunting on the suite of mechanisms driving species interactions, plant community dynamics, natural selection, trophic cascades, and ecosystem structure and function. While there are many issues relating to the pros and cons of trophy hunting, we suggest that the ecological and evolutionary discussion should focus on relevant variables and interactions that can be linked to trophy hunting.

Une réponse à la réponse :

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Conservation or the Moral High Ground: Siding with Bentham or Kant
MacDonald et al.
Conservation letters, 2016
https://ora.ox.ac.uk/objects/uuid:a91ad160-edb9-4b7c-866c-f7c88faa86c0/download_file?file_format=pdf&safe_filename=Macdonald_et_al-2016-Conservation_Letters.pdf&type_of_work=Journal+article

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People who believe that a UK ban on trophy hunting imports would cause African conservation programs to collapse should look at these graphs. pic.twitter.com/bWv0BwNNOS

— spencer 🐺 (@Unpop_Science) January 30, 2022

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Un jour, il faudra parler sérieusement de colonialisme vert… https://t.co/pWJeeIBNEI

— Fabien Abraini (@Fabiensapiens) June 19, 2022

5. Sujets d’écologie divers

Déplacé ici

How does the Living Planet Index (LPI) work? [Texte]
Robin Freeman
ZSL.org, 2022