Hin­dered cross­ings

Blocked mi­gra­tory cor­ri­dors and loss of dis­per­sal ar­eas are lim­it­ing the mi­gra­tory move­ments of an­i­mals like the wilde­beest.

The Star Malaysia - Star2 - - FRONT PAGE - By CLAIRE BEDELIANA

tHE iconic wilde­beest mi­gra­tions of East Africa are an im­por­tant eco­log­i­cal phe­nom­e­non and mas­sive tourist at­trac­tion. How­ever, many wilde­beest pop­u­la­tions are in dras­tic de­cline across the re­gion.

Their dis­per­sal ar­eas and mi­gra­tory cor­ri­dors are be­ing lost due to high hu­man pop­u­la­tion den­si­ties, in­creas­ing ur­ban­i­sa­tion, ex­pand­ing agri­cul­ture and fences. Their loss would con­trib­ute to bio­di­ver­sity de­cline, and jeop­ar­dise tourism and other ecosys­tem ser­vices. Ur­gent ef­forts need to be made to pro­tect wilde­beest mi­gra­tory cor­ri­dors and dis­per­sal ar­eas to en­sure th­ese great mi­gra­tions for the fu­ture.

Large-scale an­i­mal mi­gra­tions were once com­mon around the world, but many have now col­lapsed, and oth­ers face se­ri­ous de­cline.

For ex­am­ple, on the Great Plains of North Amer­ica, the Amer­i­can bi­son once num­bered as many as 30 mil­lion an­i­mals. To­day, only a few re­main due to over-hunt­ing.

In Cen­tral Asia, the Saiga an­te­lope has de­clined from over one mil­lion an­i­mals in 1980 to less than 200,000 in 2000.

In Kenya, the mi­gra­tion of vast herds of ze­bra and Thom­son’s gazelle be­tween the Lake Nakuru-Ele­men­taita re­gion and the Lake Baringo dis­ap­peared in the early part of the 20th cen­tury due to over-hunt­ing, habi­tat loss and other hu­man dis­tur­bances.

Sur­vival moves

The East African sa­van­nas are well known for the large-scale sea­sonal mi­gra­tions of graz­ing her­bi­vores.

Per­haps one of the most well­known is the an­nual mi­gra­tion of 1.3 mil­lion wilde­beest, 600,000 ze­bra and Thom­son’s gazelle in the Serengeti-Mara ecosys­tem. The sig­nif­i­cance of this mi­gra­tion is huge: it is the largest and most species-di­verse large mam­mal mi­gra­tion in the world. It is of iconic im­por­tance for tourism and has huge eco­log­i­cal sig­nif­i­cance, re­sult­ing in the Serengeti Na­tional Park in Tan­za­nia be­ing listed as a World Her­itage Site.

The East African sa­van­nas are highly vari­able ecosys­tems, so mi­gra­tion en­ables an­i­mals to track spa­tially and tem­po­rally vary­ing re­sources across the land­scape. This gives mi­gra­tory pop­u­la­tions an ad­van­tage over res­i­dent pop­ula- tions, and al­lows th­ese pop­u­la­tions to rise to very high abun­dances. Mi­grants may also move to ac­cess breed­ing grounds, to re­duce the risks of pre­da­tion and disease, and to en­hance their ge­netic health.

Wilde­beest mi­gra­tions are im­por­tant both eco­log­i­cally and eco­nom­i­cally. They play a vi­tal role in ecosys­tem func­tion and pro­vide a num­ber of im­por­tant ecosys­tem ser­vices. They also have a di­rect ef­fect on preda­tor pop­u­la­tions and other wildlife species, and on grass food re­sources.

Eco­nom­i­cally, wilde­beest mi­gra­tions are im­por­tant be­cause they draw in tourism and thus con­trib­ute sig­nif­i­cantly to na­tional economies. Tourism gen­er­ated an es­ti­mated US$1.2bil (RM3.9bil) rev­enue in Kenya in 2012 and US$1.3bil (RM4.3bil) in Tan­za­nia in 2011.

Wilde­beest de­pend on mi­gra­tory cor­ri­dors and dis­per­sal ar­eas as they mi­grate out of pro­tected ar­eas to their sea­sonal habi­tats, of­ten lo­cated in pas­toral lands. Mi­gra­tory cor­ri­dors and dis­per­sal ar­eas usu­ally cross hu­man-dom­i­nated land­scapes where land use prac­tices are be­com­ing in­creas­ingly in­com­pat­i­ble with wildlife. As th­ese ar­eas are de­graded or lost, se­vere de­clines in the wilde­beest pop­u­la­tions can re­sult.

In East Africa, the white-bearded wilde­beest, found across Kenya and Tan­za­nia, is fac­ing large de­clines due to in­com­pat­i­ble land uses in their mi­gra­tory cor­ri­dors and dis­per­sal ar­eas. This has oc­curred as their mi­gra­tory cor­ri­dors and dis­per­sal ar­eas have be­come blocked or lost, lim­it­ing their mi­gra­tory move­ments. The re­sult has been the near col­lapse of many wilde­beest pop­u­la­tions.

The ex­cep­tion to this gen­eral pat­tern is the Serengeti-Mara pop­u­la­tion, which in­creased six fold be­tween 1963 and 1977 fol­low­ing the erad­i­ca­tion of rinder­pest, be­fore sta­bil­is­ing to its cur­rent pop­u­la­tion of ap­prox­i­mately 1.3 mil­lion. In south­ern Africa, the blue wilde­beest is sta­ble or in­creas­ing, al­though their num­bers are still far lower than their 1960’s lev­els.

In Kenya, all four wilde­beest pop­u­la­tions are de­clin­ing dra­mat­i­cally as in­di­cated by the lat­est trends. In par­tic­u­lar, in the Mara ecosys­tem found within Narok County, the wilde­beest pop­u­la­tion that mi­grates an­nu­ally be­tween the Maa­sai Mara Na­tional Re­serve and the Loita Plains de­clined by more than twothirds, from ap­prox­i­mately 113,000 an­i­mals in 1977 to 35,000 by 2009 due to the ex­pan­sion of agri­cul­ture and con­tin­ues to de­cline.

In the Athi-Ka­putiei ecosys­tem, the wilde­beest mi­gra­tion be­tween the Nairobi Na­tional Park and the ad­join­ing Athi-Ka­putiei Plains de­clined by more than 90%, from over 30,000 in 1978 to un­der 2,000 by 2011 as a re­sult of in­creas­ing ur­ban­i­sa­tion, fenc­ing, set­tle­ments, min­ing and other de­vel­op­ments.

In Tan­za­nia, in the Tarangire-Si­man­jiro ecosys­tem, the wilde­beest mi­gra­tion from Tarangire Na­tional Park to the Si­man­jiro Plains de­clined by 88%, from 43,000 in 1988 to 5,000 in 2001 due to ex­pand­ing cul­ti­va­tion and set­tle­ments block­ing their mi­gra­tory cor­ri­dors.

Blocked paths

In each of th­ese cases, wilde­beest are pre­vented from ac­cess­ing their wet sea­son ranges due to the block­age of mi­gra­tory cor­ri­dors or the loss of habi­tat in their dis­per­sal ar­eas.

Wilde­beest are es­pe­cially vul­ner­a­ble to hu­man im­pacts in their wet sea­son ranges. Many pro­tected ar­eas in East Africa pri­mar­ily con­serve the dry sea­son habi­tat for mi­gra­tory wildlife, with the wet sea­son ranges oc­cur­ring al­most en­tirely out­side of pro­tected ar­eas on ad­ja­cent com­mu­nal or pri­vate lands.

Pro­tected ar­eas also tend to be small and were not de­signed to con­serve all of a mi­gra­tory species’ habi­tat re­quire­ments. As a re­sult, wilde­beest must jour­ney out­side of pro­tected ar­eas to reach their wet sea­son ranges. Here they face a num­ber of pres­sures due to hu­man pop­u­la­tion growth, land use change and in­creas­ing de­vel­op­ment.

In the past, pro­tected ar­eas were able to sus­tain large mi­gra­tory wilde­beest pop­u­la­tions be­cause hu­man pop­u­la­tion den­si­ties were low enough to al­low them to mi­grate out­side of pro­tected ar­eas to their wet sea­son ranges. How­ever, this is be­com­ing in­creas­ingly dif­fi­cult as hu­man pop­u­la­tions sur­round­ing pro­tected ar­eas rise, and land use changes and habi­tat loss in­ten­si­fies.

To­day, nearly all the world’s

re­main­ing large wildlife pop­u­la­tions ex­ist in un­frag­mented mi­gra­tory sys­tems. For ex­am­ple, the Serengeti-Mara ecosys­tem mi­gra­tion has been sus­tained be­cause it has sur­vived in a rel­a­tively in­tact ecosys­tem con­tained within a net­work of pro­tected ar­eas that en­com­pass all the graz­ing habi­tats re­quired to sup­port a large mi­gra­tory pop­u­la­tion. How­ever, this mi­gra­tion too now faces a num­ber of threats.

The threats

The loss or frag­men­ta­tion of habi­tats is one of the main threats to wildlife mi­gra­tions glob­ally. In East Africa, wilde­beest mi­gra­tions are in de­cline due to a num­ber of land use ac­tiv­i­ties caus­ing habi­tat loss and frag­men­ta­tion in their wet sea­son dis­per­sal ar­eas. Th­ese land use ac­tiv­i­ties, which in­clude cul­ti­va­tion, land sub­di­vi­sion, set­tle­ments, fenc­ing and other in­fra­struc­ture, dis­rupt mi­gra­tory move­ments and cause wilde­beest pop­u­la­tions to de­cline.

Fences are used to stop disease trans­mis­sion be­tween wildlife and live­stock, to pre­vent poach­ing and to pro­tect crops and homes, but they ob­struct mi­gra­tory routes.

Fenc­ing is one of the main causes of the crash in the wilde­beest pop­u­la­tion in the Athi-Ka­putiei ecosys­tem in Kenya. More than 20% of the ecosys­tem is now fenced, and a num­ber of mi­gra­tory cor­ri­dors link­ing the Nairobi Na­tional Park and the Athi-Ka­putiei Plains have been blocked by fences. Now, only few wilde­beest en­ter Nairobi Na­tional Park dur­ing the dry sea­son.

Roads, too, ob­struct mi­gra­tory routes, cause wildlife mor­tal­ity due to ve­hi­cle col­li­sions, and de­crease land­scape con­nec­tiv­ity. Due to in­creased ac­cess, roads can also open up new ar­eas for de­vel­op­ment, lead­ing to land uses in­com­pat­i­ble with wildlife. Th­ese are many of the con­cerns in the de­vel­op­ment of a new road through the Serengeti Na­tional Park.

In Kenya, a sim­i­lar threat faces the wilde­beest mi­gra­tion in the Athi-Ka­putiei ecosys­tem due to the up­grad­ing of the Athi RiverNa­manga Road and the pro­posed Greater South­ern By­pass Road along the south­ern bound­ary of Nairobi Na­tional Park.

Poach­ing is another threat to many mi­gra­tory pop­u­la­tions. In the Serengeti Na­tional Park it is es­ti­mated that lo­cal con­sump­tion of bush meat is re­spon­si­ble for ap­prox­i­mately 70,000 to 129,000 wilde­beest deaths per year. A high in­ten­sity of poach­ing is also linked to a de­cline in wildlife num­bers in the Mara area of Kenya.

Cli­mate change is a new and grow­ing threat to wildlife mi­gra­tions in the East African sa­van­nas. The in­creased fre­quency and sever­ity of droughts and floods that is ex­pected to oc­cur will mod­ify veg­e­ta­tion growth and hence food avail­abil­ity for the mi­grat­ing an­i­mals.

In the Am­boseli ecosys­tem, a se­vere drought caused the wilde­beest pop­u­la­tion to crash by more than 85% in 2009. By 2010, the pop­u­la­tion num­bered only 3,000 an­i­mals, down from over 15,000 an­i­mals be­fore the drought, the low­est ob­served for more than 30 years.

The abil­ity of mi­grants to re­spond to chang­ing cli­matic con­di­tions is likely to be im­paired by such man­made threats as habi­tat loss and frag­men­ta­tion.

What is be­ing done?

Since most mi­grants wan­der out­side of pro­tected ar­eas, it is cru­cial to in­clude com­mu­ni­ties and landown­ers in con­ser­va­tion ef­forts through par­tic­i­pa­tion in wildlife man­age­ment and ben­e­fit-shar­ing. In the East African range lands, eco­nomic ben­e­fit to lo­cal com­mu­ni­ties from wildlife has been mea­gre with lit­tle in­cen­tive to help pro­tect mi­grants or their dis­per­sal ar­eas and mi­gra­tory cor­ri­dors.

Ef­forts are now be­ing made to se­cure wildlife dis­per­sal ar­eas and mi­gra­tory cor­ri­dors through the use of com­mu­nity con­ser­van­cies, pay­ments for ecosys­tem ser­vices and other eco­nomic in­cen­tives.

For ex­am­ple, in the Mara, eight wildlife con­ser­van­cies have been formed, which of­fer land lease pay­ments of US$25 to US$40 per ha (RM82 to RM132) per year to land- own­ers. Th­ese schemes, fi­nanced by eco­tourism op­er­a­tors, aim to keep land open for wildlife and pro­vide landown­ers with a reg­u­lar in­come stream. They now cover over 90,000ha, se­cur­ing vi­tal mi­gra­tory cor­ri­dors and dis­per­sal ar­eas for wilde­beest from both the Serengeti and the Loita Plains.

In the Athi-Ka­putiei ecosys­tem, the wildlife con­ser­va­tion lease pro­gramme, sup­ported by a num­ber of donors, of­fers par­tic­i­pat­ing landown­ers US$10 (RM33) per ha per year to keep their land open for wildlife and live­stock in the wilde­beest dis­per­sal area. This pro­gramme is be­ing tar­geted to se­cure wildlife mi­gra­tory cor­ri­dors and crit­i­cally re­duce fenc­ing in this ecosys­tem and by 2012 cov­ered 24,200ha.

In another ap­proach, en­vi­ron­men­tal ease­ments are be­ing ap­plied to pro­tect pri­vately owned land ad­ja­cent to Nairobi Na­tional Park, in­clud­ing plac­ing it un­der park man­age­ment.

Also in this ecosys­tem, the com­mu­nity and other stake­hold­ers have re­cently de­vel­oped the first com­mu­nity driven lan­duse mas­ter­plan to sus­tain­ably man­age wildlife dis­per­sal ar­eas along­side live­stock graz­ing, set­tle­ments and other land uses in the ecosys­tem.

In the Tarangire-Si­man­jiro ecosys­tem in Tan­za­nia, pay­ments for ecosys­tem ser­vices, fi­nanced by tour op­er­a­tors, are be­ing used to pro­tect the dis­per­sal area of mi­gra­tory wilde­beest and other wildlife in the Si­man­jiro plains.

Un­der­stand­ing mi­gra­tion

Con­serv­ing mi­gra­tory routes re­quires im­ple­ment­ing con­ser­va­tion plans be­yond pro­tected area bound­aries. Dis­per­sal ar­eas and mi­gra­tory cor­ri­dors can be kept open for wildlife, by en­cour­ag­ing wildlife-friendly land uses, and the co-op­er­a­tion and par­tic­i­pa­tion of com­mu­nity and pri­vate landown­ers.

Gov­ern­ments need to pro­vide the cor­rect en­abling pol­icy and leg­isla­tive en­vi­ron­ment to sup­port the types of ini­tia­tives al­ready emerg­ing to pro­tect mi­gra­tory habi­tat.

Due to the trans­bound­ary na­ture of wilde­beest mi­gra­tion in East Africa, the re­spec­tive coun­tries and gov­ern­ments need to work to­gether to mit­i­gate threats to the mi­gra­tions.

Good sci­en­tific in­for­ma­tion on where, when and why wildlife mi­gra­tions oc­cur is needed to in­form con­ser­va­tion and man­age­ment de­ci­sions. This in­cludes map­ping the move­ments and ranges of wilde­beest, the eco­log­i­cal driv­ers of mi­gra­tion, pop­u­la­tion lev­els, and a good un­der­stand­ing of the threats to mi­grants and their habi­tats.

The Kenya and Tan­za­nia gov­ern­ments are al­ready map­ping wildlife cor­ri­dors and mi­gra­tory routes with the aim of se­cur­ing crit­i­cal wildlife ar­eas.

In other ini­tia­tives, re­searchers are col­lar­ing wilde­beest to track their move­ments to un­der­stand how land­scape frag­men­ta­tion and cli­mate change are af­fect­ing wilde­beest, and re­port­ing their move­ments online.

Ef­forts to se­cure dis­per­sal ar­eas and mi­gra­tory cor­ri­dors will re­quire an in­te­grated ap­proach to land use plan­ning both in­side and out­side of pro­tected ar­eas. By tak­ing into ac­count wildlife and their mi­gra­tory routes, peo­ple, live­stock, land­scapes and nat­u­ral re­sources, a more com­pre­hen­sive con­ser­va­tion ef­fort can be made.

Thus, there is a need to work col­lab­o­ra­tively with landown­ers and users to iden­tify threats along mi­gra­tory routes so th­ese crit­i­cal ar­eas can be ef­fec­tively pro­tected.

The rapid and dra­matic wilde­beest pop­u­la­tion de­clines in East Africa calls for ur­gent, com­pre­hen­sive and de­ci­sive remedial steps to pro­tect the re­main­ing pop­u­la­tions and re­ha­bil­i­tate their habi­tats. This will en­hance their re­silience to the in­ten­si­fy­ing droughts and con­trib­ute to the sus­tain­abil­ity of lo­cal liveli­hoods. – UNEP

Mov­ing house: Wilde­beest and ze­bra mount the op­po­site bank af­ter cross­ing the Mara river, in the Maa­sai Mara Game re­serve in Kenya. The an­nual mi­gra­tion of wilde­beest, ze­bra and Thom­son’s gazelle in the Serengeti-Mara ecosys­tem is the largest and most species-di­verse mam­mal mi­gra­tion in the world. – aP

croc­o­diles devour a ze­bra as it at­tempts to cross a river.

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