1,4 1 1 2Colin Courtney-Mustaphi *, Rob Marchant , Esther Githumbi , Veronica Muiruri ,2 2 3,1 4 4Stephen Rucina , Rebecca Muthoni , Suzi Richer , Paul Lane , Anna Shoemaker

1 University of York Institute for Tropical Ecosystems, UK2 National Museums of Kenya, Nairobi, Kenya3 Dept. of Archaeology, University of York, UK

4 Dept. of Archaeology and Ancient History, University of Uppsala, Sweden* Email: colin.courtney-mustaphi@york.ac.uk

Wetland vegetation dynamics in the semi-arid Amboseli landscape of southern Kenya

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Depth (cm)

ESAM2c

ESAM2b

ESAM2a

ESAM1

Podocarpus

0 20

Juniperus

0 20

Celtis

0 20

Croton

0 20

Olea

0 20

Schefflera

0 20

Acacia

0 20

Balanites

0 20

Capparis

0 20

Commiphora

0 50

Cordia

0 50

Terminalia

0 20

Acanthaceae

0 50

Acalypha

0 20

Aloe

0 50

Apocynaceae

0 20

Asteraceae

0 100

Amara/chenop

0 20

Brassicaceae

0 20

Cadaba

0 20

Cucurbitaceae

0 50

Impatiens

0 20

Indigofera

0 50

Justicia

0 50

Liliaceae

0 20

Rhus

0 20

Rumex

0 50

Salvadora

0 50

Tapura

0 20

Umbelliferae

0 100

Urticaceae

0 20

Poaceae>60µm

0 100

Poaceae

Pinus

0 50

Nymphaea

0 100

Cyperaceae

0 100

Typha

0 2000

Charco

al>1

25µm

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400

cal yr BP

AFROMONTANE WOODLAND SHRUB/GRASSLAND AQUATIC

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% terrestrial pollen sum % aquatic sum -3No. cm

sumof

squares

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40 60 80 100

Cyp

erac

eae

0 10 20

Typha

0 1

Ludw

igia

0 5

Hyd

roco

tyle

0 2

Polyg

onum

Pavon

ia

0 10 20

Com

mel

ina

0 2

Justicia

Cuc

urbita

ceae

0 15

Poace

ae

0 15

Aster

acea

e

0 10 20

Amar

a/Che

no

0 10 20

Solan

um

Acant

hace

ae

0 1

Syzyg

ium

Borag

inac

eae

0 10

Tribulus

0 3

Eupho

rbia

0 8

Acacia

0 10

Com

mip

hora

0 4

Cap

parid

acea

e

0 10

Mae

sa

Acalyp

ha

Ipom

oea

Poute

ria

Phylant

hus

0 3

Mal

vace

a

Ole

aJu

nipe

rus

Podoc

arpu

s

Artem

isia

Stoeb

e

Ericac

eae

Aquatics Herbaceous Semi-arid savannah Semi-arid Shrubland-Woodland Montante forest Ericaceous

Introduction

Methods

Results and discussion

Amboseli, near the Kenya-Tanzania border, is a relatively flat landscape, punctuated by volcanic cone fields and intermittent palustrine wetlands (Figs1-3).Water is primarily sourced from orographic precipitation on Mt Kilimanjaro that sustains the swamps (Fig4).Since the 1980s, the swamps have been increasingly converted to agriculture, except those in the National Park (Fig3).The wetlands are a critical link for wildlife and pastoralist corridors between national parks.Recent changes to precipitation on Mt Kilimanjaro and the impacts of occasional drought are a major threat to socio-ecological resilience.

Amboseli basin

Mt Kilimanjaro

Chyulu H

ills

Tsavo

NP

Enkongu

Namelok

Ormakau

Esambu

Kimana

Amboseli National Park

Fig1: Location in Africa Fig2: Amboseli region, international border in red.

KenyaTanzania

Fig3: Intermittent wetlands fed by springs and river channels.

Geo-h

ydro

clim

atic

pro

cess

es

Isolatedconvective precipitation

Orographic precipitationEvapotranspiration

Lithosphere

Biosphere

Atmosphere

Groundwater

SurfaceSprings

KilimanjaroAmboseli Plains

Lower M

ontane

Upper M

ontaneAlpine

Saturated zone

Phreatic zone

Vadose zone

Volcanic cones

Water table

Large volcanic cones

La

nd

sca

pe

fe

atu

res

Ch

an

ne

l

Sw

am

p

Sw

am

pfo

rest

Sava

nnah

Dryla

nd

Volcaniccones

Pool

Ephemeral

Endorh

eic b

asin

Rip

aria

n

fore

st

Mo

un

tain

Rech

arg

e z

one

Fig4: Mt Kilimanjaro, the orographic water tower.

Cyperaceae wetlandCyperaceae wetland Wetlands and surrounding moist soils Savannah Semi-arid scrub and woodland Arid scrub and volcanic ejecta

Water channeling Walled spring source areas Intensive agriculture

Land c

ove

rLand u

ses

To examine long-term variability of the wetlands, we cored multiple sites using a Russian corer, and radiocarbon dated the stratigraphies.Pollen analysis and macrocharcoal has been completed on 5 sites.

All coring sites dated <5000 cal yr BP, suggesting that their sediments have been accumulating since to termination of the African Humid Period.Pollen data show that woody compositions near the swamps varies spatially and temporally, evidence of the heterogeneity and complexity of the landscape.Archaeological evidence in the area suggests extensive hunter-gatherer livelihoods until the recent and unprecendented land use changes.

Esambu pollen record

Enkongu pollen record

Ongoing work continues to analyse the pollen and charcoal data alongsidearchaeological survey and pits acrossAmboseli.