‘Sixth ex­tinc­tion’ of world’s wildlife faster than feared

Sci­en­tists blame hu­mans for ac­cel­er­at­ing loss of bio­di­ver­sity

China Daily (Hong Kong) - - WORLD -

PARIS — The sixth mass ex­tinc­tion of life on Earth is un­fold­ing more quickly than feared, sci­en­tists have warned.

More than 30 per­cent of an­i­mals with a back­bone — fish, birds, am­phib­ians, rep­tiles and mam­mals — are de­clin­ing in both range and pop­u­la­tion, ac­cord­ing to the first com­pre­hen­sive anal­y­sis of these trends.

“This is the case of a bi­o­log­i­cal an­ni­hi­la­tion oc­cur­ring glob­ally,” said Stan­ford pro­fes­sor Rodolfo Dirzo, co-au­thor of a study pub­lished on Mon­day in the peer-re­viewed US jour­nal, Pro­ceed­ings of the Na­tional Academy of Sci­ences.

Around a decade ago, ex­perts feared that a new plan­e­tary wipe­out of species was loom­ing.

To­day, most agree that it is un­der­way — but the new study sug­gests that the die-out is al­ready ratch­et­ing up a gear.

It pro­vides much-needed data about the threat to wildlife, map­ping the dwin­dling ranges and pop­u­la­tions of 27,600 species. For 177 mam­mals, re­searchers combed through data cov­er­ing the pe­riod 1900 to 2015.

The mam­mal species that were mon­i­tored have lost at least a third of their orig­i­nal habi­tat, the re­searchers found.

Forty per­cent of them — in­clud­ing rhi­nos, orang­utans, go­ril­las and many big cats — are sur­viv­ing on 20 per­cent or less of the land they once roamed.

The loss of bio­di­ver­sity has re­cently ac­cel­er­ated.

“Sev­eral species of mam­mals that were rel­a­tively safe one or two decades ago are now en­dan­gered,” in­clud­ing chee­tahs, lions and gi­raffes, the study showed.

Glob­ally, the mass die-off — deemed to be the sixth in the last half-bil­lion years — is the worst since three-quar­ters of life on Earth, in­clud­ing the non-avian di­nosaurs, were wiped out 66 mil­lion years ago by a gi­ant me­teor im­pact.

There is no mys­tery as to why: our own ever-ex­pand­ing species — which has more than dou­bled in num­ber since 1960 to 7.4 bil­lion — is eat­ing, crowd- ing and pol­lut­ing its plan­e­tary co­hab­i­tants out of ex­is­tence.

By com­par­i­son, there are as few as 20,000 lions left in the wild, less than 7,000 chee­tahs, 500 to 1,000 gi­ant pan­das and about 250 Su­ma­tran rhi­noc­eros.

Main driv­ers

The main driv­ers of wildlife de­cline are habi­tat loss, over­con­sump­tion, pol­lu­tion, in­va­sive species, dis­ease, as well as poach­ing in the case of tigers, ele­phants, rhi­nos and other large an­i­mals prized for their body parts.

Cli­mate change is poised to be­come a ma­jor threat in the com­ing decades, with some an­i­mals — most fa­mously po­lar bears — al­ready in de­cline due to ris­ing tem­per­a­tures and chang­ing weather pat­terns.

“The mas­sive loss of pop­u­la­tions and species re­flects our lack of em­pa­thy to all the wild species that have been our com­pan­ions since our ori­gins,” said lead au­thor Ger­ardo Ce­bal­los of the Na­tional Au­ton­o­mous Univer­sity of Mex­ico.

Be­yond any moral im­per­a­tive, there are prac­ti­cal rea­sons to rue the eclipse of an­i­mals, whether megafauna or smaller and less “charis­matic” crea­tures, the re­searchers said.

The van­ish­ing of a top-level car­ni­vore or her­bi­vore can have a cas­cad­ing ef­fect down the food chain, dis­rupt­ing en­tire ecosys­tems.

Other species di­rectly pro­vide “ser­vices” to hu­mans, such as honey­bees that pol­li­nate crops or birds that en­sure pest con­trol.

Pre­vi­ous stud­ies show that ecosys­tems un­der stress, while re­silient, have a break­ing point — rapid change can lead to col­lapse.

The mas­sive loss of pop­u­la­tions and species re­flects our lack of em­pa­thy to all the wild species.”

Ger­ardo Ce­bal­los, study au­thor


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