A Col­lec­tion of News by Moos


Wide­spread local extinc­tions in trop­i­cal for­est ‘remnants’

pub­lished 15 August 2012 | mod­i­fied 05 Decem­ber 2012

The small frag­ments of trop­i­cal forests left behind after defor­esta­tion are suf­fer­ing exten­sive species extinc­tion, accord­ing to new research led by the Uni­ver­sity of East Anglia and pub­lished in the jour­nal PLoS ONE on August 14, 2012.

The researchers car­ried out a com­pre­hen­sive assess­ment to esti­mate the long-​term impact of for­est frag­men­ta­tion and hunt­ing on trop­i­cal bio­di­ver­sity in Brazil. They stud­ied the Atlantic For­est of east­ern Brazil, includ­ing the region’s largest and least dis­turbed old-​growth for­est rem­nants, and found that remain­ing habi­tat frag­ments had been vir­tu­ally emp­tied of their for­est wildlife. White-​lipped pec­ca­ries were com­pletely wiped out, while jaguars, low­land tapirs, woolly spider-​monkeys and giant anteaters were vir­tu­ally extinct. Defau­na­tion even extended to for­est rem­nants with rel­a­tively intact canopy structures.

You might expect for­est frag­ments with a rel­a­tively intact canopy struc­ture to still sup­port high lev­els of bio­di­ver­sity. Our study demon­strates that this is rarely the case, unless these frag­ments are strictly pro­tected from hunt­ing pres­sure. There is no sub­sti­tute for strict pro­tec­tion of remain­ing for­est frag­ments in bio­di­ver­sity hotspots like the Brazil­ian Atlantic For­est. Pro­tec­tion of for­est cover alone is not enough to sus­tain trop­i­cal for­est species, as over­hunt­ing com­pounds the detri­men­tal effects of small habi­tat area and isolation
Prof Car­los Peres, senior author, Uni­ver­sity of East Anglia’s School of Envi­ron­men­tal Sciences »

Wide­spread agri­cul­tural expan­sion has trans­formed the world’s trop­i­cal forests, leav­ing few remain­ing blocks of pri­mary forests unal­tered by humans. There have been scat­tered reports of large mam­mal extinc­tions through­out Brazil, but the con­ser­va­tion value of a rapidly grow­ing num­ber of small for­est rem­nants in highly-​fragmented trop­i­cal for­est land­scapes has been hotly debated.

forest area occupiedDraw­ing on infor­ma­tion from wildlife sur­veys and local inter­views con­ducted at 196 for­est frag­ments span­ning a vast region cov­er­ing 252.670 km2, Dr Peres worked in part­ner­ship with Dr Gus­tavo Canale of the State Uni­ver­sity of Mato Grosso (UNE­MAT). They inves­ti­gated the effects of anthro­pogenic land­scape alter­ation and other impacts, such as hunt­ing, on the sur­vival of large ver­te­brate species. The researchers trav­elled more than 205,000 km by treach­er­ous dirt roads to uncover the largest and least dis­turbed for­est frag­ments left in this vast region of the Atlantic Forest.

“We uncov­ered a stag­ger­ing process of local extinc­tions of mid-​sized and large mam­mals,” said Dr Canale.

Around 90 per cent of the orig­i­nal Atlantic For­est cover (about 1.5 mil­lion km2) has been con­verted to agri­cul­ture, pas­ture and urban areas, and most of the remain­ing for­est patches are smaller than a foot­ball pitch. On aver­age, for­est patches retained only four of 18 mam­mal species surveyed.

This study — the first to doc­u­ment the loss of five large trop­i­cal for­est mam­mals from one of the world’s most endan­gered trop­i­cal bio­di­ver­sity hotspots — high­lights the crit­i­cal impor­tance of the few legally pro­tected areas estab­lished in the Atlantic Forest.

“We found that the pro­tected areas retained the most species-​rich for­est frag­ments in the region,” said Dr Canale. “We there­fore rec­om­mend the imple­men­ta­tion of new strictly pro­tected areas, such as National Parks and Bio­log­i­cal Reserves, includ­ing for­est frag­ments con­tain­ing pop­u­la­tions of endan­gered, rare and endemic species, par­tic­u­larly those fac­ing immi­nent extinctions.”

How­ever, many of the exist­ing pro­tected areas are far from secure. Prof Peres said: “A grow­ing num­ber of reserves are being degraded, down­sized, if not entirely degazetted, so hold­ing on to the last remain­ing large tracts of pri­mary forests will be a cru­cial part of the con­ser­va­tion mis­sion this cen­tury.” With the global pop­u­la­tion pro­jected to sur­pass nine bil­lion by 2050, trop­i­cal forests will face increas­ing threats posed by anthro­pogenic land-​use change and overexploitation.

Human pop­u­la­tions are explod­ing and very few areas remain untouched by the expand­ing cor­nu­copia of human impacts. It is there­fore essen­tial to enforce pro­tec­tion in areas that are nom­i­nally pro­tected ‘on paper’. The future of trop­i­cal for­est wildlife depends on it
( Prof Car­los Peres)

(Source: UEA Press Release, 14.08.2012)

UN Biodiversity decade

Goal: 7000 tigers in the wild

Tiger range countries map

Tiger map” (CC BY 2.5) by Sander­son et al., 2006.

about zoos and their mis­sion regard­ing breed­ing endan­gered species, nature con­ser­va­tion, bio­di­ver­sity and edu­ca­tion, which of course relates to the evo­lu­tion of species.
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