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www.environnement.ens.frENS Centre de formation sur l’environnement et la société
1www.environnement.ens.fr
Ecole Normale Supéreure 24 rue Lhomond, 75005 Paris, Rez-de-chaussée, bureaux E026
UE CERES-AA-05-S1 David Claessen
Introduction à l’environnement et la biodiversité
www.environnement.ens.frENS Centre de formation sur l’environnement et la société
2www.environnement.ens.fr
Ecole Normale Supéreure 24 rue Lhomond, 75005 Paris, Rez-de-chaussée, bureaux E026
UE CERES-AA-05-S1 David Claessen
The tragedy of the commons in ecology, evolution and environmental science
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The«commons»
• «Common»=«villagegreen»
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WilliamForsterLloyd(1833)• Pasturelandsle@opentomanyherdsof
caClewitharesourceavailabletoall,• thegreediestherdsmenwouldgain—fora
while• Mutualruinwasjustaroundthecorner.• AsdemandgrewinstepwithpopulaHon
(whilesupplyremainedfixed),aHmewouldcomewhentheherdsmen,acHngasSmithianindividuals,wouldbetrappedbytheirowncompeHHveimpulses.
• Theunmanagedcommonswouldberuinedbyovergrazing
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www.environnement.ens.frENS Centre de formation sur l’environnement et la société
D'oùvientleproblème?
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ThomasRobertMalthus
• Geometrical population growth
• The increase of population is necessarily limited by the means of subsistence;
• The superior power of population is repressed, and the actual population kept equal to the means of subsistence, by misery and vice.
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S = resource X = consumer population abundance
Fitness W =
Fitness is defined as the per capita exponential growth rate
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www.environnement.ens.frENS Centre de formation sur l’environnement et la société
D'oùvientleproblème?
II
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1609,HugodeGroot(HugoGro(us):“Thefreedomoftheseas”
« Peter Pett and the Sovereign of the Seas » Peter Lely (1637)
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1625,HugodeGroot(HugoGro(us):“Theextentoftheoceanisinfactsogreatthatitsufficesforanypossibleuseonthepartofallpeoplesfordrawingwater,forfishing,forsailing.”
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« I know the human being and fish can coexist peacefully »
Saginaw, Michigan; September 29, 2000
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«Freedomoftheseas»incombinaHonwith«theinvisiblehand»(AdamSmith1776)
àTragedyofthecommons
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Oceanic ecosystems Shelf ecosystems
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