8/13/2019 Africa Great Rift Valley Art

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LAKE

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Lake

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Kivu

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AKE

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LakeRuk

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Lake George

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Nyiragongo11,385ft3,470m

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SEMULIKI

NAT. PARK

RWENZORI MTS.

NAT. PARK

VIRUNGA

NATIONAL

PARK

MURCHISON

FALLS

NATIONAL

PARK

NSUMBU

NATIONAL

PARK

QUEEN

ELIZABETH

NATIONALPARK

MAHALE MTS.

NATIONAL

PARK

KIBALENATIONALPARK

BWINDI IMPENETRABLE

NAT. PARK

GOMBE STREAM

NAT. PARK

MGAHINGA

GORILLA

NAT. PARK

VOLCANS NAT. PARK

A

A

Goma

Bunia

Uvira

Uvinza

Kigoma

Kigali

Huye(Butare)

Bukavu

Butembo

Rubavu(Gisenyi)

Muyinga

Bujumbura

Musanze (Ruhengeri)

RWANDA

TANZANIA

UGANDA

DEMOCRATIC

REPUBLIC

OF THE

CONGO

BURUNDI

DEMOCRATIC

REPUBLIC

OF THE

CONGO

ZAMBIA

TANZANIA

UGANDA

BURUNDI

RWANDA

TANZANIA

ZAMBIA

BURUNDI

RWANDA

UGANDA

SOUTHSUDAN

DEMOCRATIC

REPUBLIC

OFTHE

CONGO

Lowla nd

Forest

Lowl and

Forest

FloodedGrassland

FloodedGrassland

FloodedGrassland

ThicketFlooded

Grassland

The western arm of Africas Great Rift Valleythe Albertine Riftembraces such

rich and varied habitats that its wildlife diversity is unparalleled on the continent.

With deep freshwater lakes filling the valleys spine (map, far left), the Albertine spans

mountains, marshes, savannas, and active volcanoes. The geologic forces that created

this rift valley are still in motion, most visibly at its center, around Lake Kivu (below).

TODAY

10 MILLIONYEARS AGO

Tectonicplatesbegin to moveapart asmagmarises. A shallowvalley forms, with alowescarp-ment, orridge, along afault line.Lavaoozesup through fissuresand coolsinto sheetsof rock.

7.5 MILLIONYEARS AGO

More magmarises asthe landcontinuestostretchand fracture.Volcanicconesbegin to dotthe valley. Faulting causesthewest side ofthe valley to sink,heightening the escarpment.

3 MILLIONYEARS AGO

The widening rift valley sinksfurther, creating an escarpmenton the east. Streamsflowing fromthe western highlandsfillan earlyLake Kivu. Erupting volcanoeswillform the VirungaMountains.

Splitting a ContinentAfricasGreat Rift Valley followsthe edgesof tectonic

platesthat merged more than abillion years ago. Now

the platesare separating, or rifting, along those seams.

The Arabian plate wasthe first to split off, starting 30 to

25 million yearsago. In another30 million years, riftingmay cleave the Somalian plate fromthe main continent

and detach the block called the Tanzaniacraton.

The Albertine ArkTheAlbertineRift cradlesmorethan 850speciesfound

nowhereelseincludingtherare mountaingorilla(about

780remain) andthe venomousGreatLakesbush viper.

There are familiarfacestoo: More than 50 percent

ofthecontinentsbirdspeciesandalmost40percentof

itsmammal specieslivehere. Theillustratedscenesat

bottomhighlightfour vitalAlbertineecosystems.

A MONTANE FOREST B ALPINE MOORLAND

The Great

C LAKE AND WETLAND D SAVANNA-FOREST MOSAIC

Covering the lowerslopes ofmountains and the high-landsflanking the valley, thisecosystemholds the riftsgreatest number of endemic species. Flamboyant birdsand chameleonsand 11 speciesofmonkeysshare theforest with the web-toed Ruwenzoriotter shrew, aboutafoot long, which catchescrabs and insectsin streams.

Ataltitudesabove10,000 feet,themisty RwenzoriMountainsandthe volcanicVirungachainshelterother-worldlyplantsheathersas tallastrees andtoweringlobelias.Thickfur warmsthetree hyrax,adistant relativeofthe elephant.Twoendangeredprimates,themountaingorillaandthe goldenmonkey,survivehere.

Papyrusis the sole perch ofthe red-breasted papyrusgonolek. Along with otherwetland vegetation, papyrusfrondsform supportive matsfor aquaticantelope calledsitatungas. The Congo clawlessotterfishes here andalso digs for giant earthworms in pockets of swampyforest clearingsscattered about the rift.

Two rainy seasonsayear bring abundant grassfor thesavannas grazing topi and Uganda kobprey for the toppredators,lions,and forscavengingvulturesand eagles.As elephants push over trees while feeding on branchesand leaves, grassland expands. Naturalfiresfrequentlysweep through, priming the savannaforregeneration.

DYNAMICS OF LIFE IN THE ALBERTINE RIFT

Rift Valley

Blue-headedsunbird

Ruwenzoriduiker

Shoebillstork

Hippopotamus Africanlion

Africanelephant

Mountaingorilla

Giantlobelia

Parrotimpatiens

Red hotpoker flower

Uganda giantcycad

Great Lakesbush viper

Extreme variation in altitude and

climate contributesto the Albertinesbiodiversity. This elevation profile ofhabitats, with theirtypicalplantsandanimals, tracesthe 82-mile-long crosssection marked on the map at farleft.

HEAVILY CULTIVATED AREA

Rwenzori Mountains

Alpine moorl and

Montane forest Montane forest

Lake and wetland

L a k e G e o r g e

UGANDADEMOCRATICREPUBLICOFTHE CONGO

Savanna-forest mosaic

THREATS Eveninprotectedareas, forestsare clearedforfarmland and fuel; goldmining isfouling streams.

THREATS The warmingtemperaturesof climatechange could shrink thisalready restricted habitat.

THREATS Overfishing istaxing lake stocks, andwetlandsare being drainedto expand farmland.

Nyiragongo

Goma

Lake Kivu

Rising magma

Fault

Lavabeds

Lavaoozesthrough fissuresin Earthscrust.

Westernescarpment

Volcaniccones

Easternescarpment

Streamsflowfromhighlandsinto an earlyLake Kivu.

Solidified layersofvolcanicrock

Arrowsindicaterelative motion oftectonicplates.

Lake sedimentsatoplayersofvolcanicrock

Faults

ENDEMIC (FOUNDNOWHEREELSE)

NOTENDEMIC

Ruwenzorituraco

Yellow-crestedhelmet shrike

LHoestsmonkey

Ruwenzoriotter shrew

Strange-nosedchameleon

Tree hyrax

Goldenmonkey

Mountain gorilla

Goliath heron

Sitatunga

Hippopotamus

African pygmygoose

Congoclawlessotter

Blue-headedcoucal

Lion

Uganda kob

Topi

Lappvultu

Giraffe

Elephant

Total species

8,668MAMMALS 385

BIRDS 1,074

REPTILES 177

AMPHIBIANS 143

FISH 480

PLANTS 6,409

Endemic

854MAMMALS 45

BIRDS 42

REPTILES 18

AMPHIBIANS 38

FISH 370

PLANTS 341

Threatened

175MAMMALS 36

BIRDS 25

REPTILES 2

AMPHIBIANS 15

FISH 24

PLANTS 73

Carbon dioxide bubblesup anddissolvesin the lakesdepths.

Lavaflowfrom2002 eruption

Acacia tree

Cand

Papyrus

Giant lobelia

Papyrusgonolek

Giantheather

Disa stairsii

orchid

Giantgroundsel

12,500 ft

15,000 ft

10,000 ft

7,500 ft

5,000 ft

SOMALIANPLATE

SOMALIANPLATE

NUBIAN(AFRICAN)

PLATE

TANZANIACRATON

ARABIAN PLATE

Madagascar

Madagascar

TANZANIACRATON

NUBIAN(AFRICAN)

PLATE

ARABIAN PLATE

EasternRift

EthiopianRift

WesternRift

(Albertine)

INDIAN

OCEAN

GulfofA

den

RedSea

AFRICA

Realms of the AlbertineFromLake Albert through Lake Tanganyika, the 920-mile-long rift

holdsfourecosystemsvitalto itsbiodiversity.Withfertile volcanic

soiland amplerain,it alsosupportsone ofAfricasdensesthuman

populations,mainlysubsistencefarmers.Wildlifeconservationhere

also looksto healwoundsof war:Conflictsover land, resources,

and powerhave killed millionsof people in the past two decades.

AN

SNAT. PARK

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Speciesnumbers,fromtheWildlifeConservationSociety,arebestestimatesasof2011andconsideredtobeminimums.

ALBERTINERIFT ECOSYSTEMS

Westernescarpment

A

B

C

D

A

B

C

D

N

Areashownin Lake Kivugeology diagrams(right top)

30 MILLIONYEARS

FROM NOW

TODAY

Three volcanoesremain active. Nyiragongoerupted in 1977 and 2002, taking lives anddisplacing hundredsof thousandsofpeople.Moltenrock beneath1,600-foot-deepLakeKivureleasescarbon dioxide, which getstrappedin the lake. Ifan earthquake or eruption freedthe gas, along with trapped methane, thedeath tollwould be catastrophic.

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POPUL TIONDENSTYPOPULATIONDENSITYPeople persq km sq mPeople persq km(sq mi)50 (130)

100 (260)

200 (520)

500 (1,300)

1,000 (2,600)

DESIGN: JUAN VELASCO TEXT:SHELLEY SPERRYART:ALDO CHIAPPE WILDLIFE,GARY HINCKS GEOLOGYRESEARCH:BARBARA L.WYCKOFF PRODUCTION: SANDI OWATVEROTNUZZO CONSULTANTS: ALEXANDRIA L. GUTH, MICHIGAN TECHNOLOGICAL UNIVERSITY;ANDREW J. PLUMPTRE, WILDLIFE CONSERVATION SOCIETY;JOHN BATES AND VELIZAR SIMEONOVSKI, FIELD MUSEUM; HENK BEENTJE,ROYAL BOTANIC GARDENS, KEW; JULIAN KERBIS, ROOSEVELT UNIVERSITY; JOS SNOEKS, ROYAL MUSEUM FOR CENTRAL AFRICAMAPS:ROSEMARY P.DALEY,DEBBIE GIBBONS,JULIE A.IBINSON,JAMES E.MCCLELLAND,JR.MAP DATA: TERRESTRIAL ECOREGIONS GISDATABASE,WORLD WILDLIFE FUND;SRTM DATA,INTERNATIONAL CENTRE FOR TROPICAL AGRICULTURE;NASAEARTH OBSERVATORY;MODIS/TERRA VEGETATION CONTINUOUS FIELDS,NASA;UMD GLOBAL LAND COVER CLASSIFICATION,UNIVERSITY OF MARYLAND;OAK

RIDGE NATIONAL LABORATORY LANDSCAN2009/UTBATTELLETECTONIC MAPS: STANISLAW MAZUR,GETECH;AFAR RIFT CONSORTIUM,UNIVERSITY OF LEEDS DATA

MORE ON NATIONAL GEOGRAPHIC MAPS AND ITS PRODUCTS AT NATGEOMAPS.COM OR CALL 18009621643

COPYRIGHT 2011 NATIONAL GEOGRAPHIC SOCIETY, WASHINGTON, D.C. PRINTED SEPTEMBER 2011

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The elevationprofile offourecosystems(rightcenter)followsthis82-mile-longcrosssection.

THREATENED ORVULNERABLE

ENDANGERED

SPECIESKEY

Magma

Bottego 15,418 ft

Musanze(Ruhengeri)

UGANDA

RWANDA

Rubavu(Gisenyi)

UGANDADEM.REP.OFTHECONGO

DEM

.

REP

.OFTH

ECONGO

RWANDA

7SEVEN BILLION S PECIAL S ERIES

0 mi 100

0 km 100

A Montaneforest

B Alpinemoorland

C Lake andwetland

D Savanna-forestmosaic