13
Wetland habitats,their
resourcepotentialand
exploitation
A casestudy from the Humber wetlands
Mark Dinnin & Robert Van de Noort
AesrRAcr:The notion that wetlandsare amongthe most productive environmentsin the world is widely
quoted, but its relationship with the exploitation of wetland ecosystemsduring the prehistoric and
early historic period hasbeenthe subjectof few investigations.The currentpaper discussesthe primary
production of different wetland habitatsand its relationshipto the resourcepotential of thesehabitats
and their actual exploitation, using recent results from the Humber Wetlands Survey. It is arguedthat
during the early Holocene,wetland landscapeswere centralto the subsistenceeconomy and that a clear
associationexistsbetweenthe primary productivity of wetlandsand the intensity of exploitation. With
the rntroductionof agriculture,however,wetlandhabitatsbecomeincreasinglyperipheralto the economy.
Introduction
Wetlands, comprising a wide range of
landscapeswhich aresituatedin thetransitional
zone between terrestrial and aquatic
environments,are widely quoted as being
among the most biologically productive
ecosystemsin the world (e.9.Coles& Coles
1989;Williams 1990;Denny1995).However,
biological productivityvaries greatlybetween
the many habitats in this transitional zone,
which is not onlyreflectedin theirbiodiversity,
but also in the resourcepotential and diverse
exploitationof the rangeof wetlandlandscapes
in the past. This paper assessesbiological
productivity, resourcepotential and human
exploitation of vanouswetlandhabitatsduring
the Holocene.The resultsfrom the initial two
years of researchby the Humber Wetlands
Survey are usedto illustrate the relationship
betweenbiological productivityandexploited
resourcepotential in the Humber wetlands,
which contains a diverse range of wetland
environments.
The Humber wetlands are located in the
lowlands around the estuary of the River
Humber,in thenorth-eastofEngland(fig.13.1).
The River Humber emergesat the confluence
of the Rivers Ouse and Trent and drains
approximately one-fifth of the landmassof
England(Pethick1990).The lowlandsaround
the Humber are dissectedby higher, free-
draining groundson both the north and south
side of the estuary,leaving seven lowland
regionswithin the Humber wetlands,eachwith
their particular physiographiccharacteristics
(Van deNoort & Davies1993).
With the exceptionof the lakes,or meres,
in the region of Holdernessthe development
of the wetlands in the region is closely
associatedwith sea-levelrise during the LateglacialandHolocene,andthe region forms the
focus for various studies into marine
transgressions
andregressions(e.g.Gaunt&
Tooley 1973;Dinnin & Lillie 1995;cf. Parkes
1996).The developmentof wetlands during
t h e L a t e - g l a c i a la n d H o l o c e n e ,m a y b e
summarisedasfollows: afteran initialbraiding
of riversbeforec.10,000BP(Jones& Gaunt
I976), the wetlands in the region comprised
mainly rivers which followed well defined,
incisedcourses,plus the lakesin Holderness
which developedin depressionsin the morainic
landscapeleft by glacial and glaciofluvial
activity.From c.1800cal.BC(c.4000BP),
the
run-off of therivers was increasinglyimpeded
due to marine transgression,resulting in
overbankfloodingsandpaludification,andlarge
scale floodplain mire development.In the
Humberhead Levels region, in areas with
podzolic soils where drainagewas impeded,
theraisedmiresof ThorneandHatfield Moors
. l
:
't
s
t.
69
F
Dinnin & Van de Noort
developedfrom the mid-Holoceneonwards.
Wetland developmentcontinueduntil large
scaledrainageschemeswere introducedto the
region in the early seventeenthcentury
(Sheppard1956;Dinnin 1997a).
In view of the well-established
archaeologicalandenvironmentalpreservation
potentialof all wetlands,and the widespread
threatsto this resourcein the Humberwetlands,
particularlyby drainageandploughing,English
Heritagecommissionedthe HumberWetlands
Survey in 1994. The work is undertakenby
the Humber Wetlands Project, which is
currently based in the Centre for Wetland
Archaeologyat the University of Hull. The
work involves the systematicfield survey of
selected areas in each of the seven
physiographicregionsin the Humberwetlands.
The systematic survey includes integrated
programmes of archaeological and
research,aimed at the
palaeoenvironmental
remainswithin
identificationof archaeological
(Van
development
the contextofpast wetland
de Noort & Ett6 1995).Thus far, the survey
of three regions in the Humber wetlands,
70
Holderness,the HumberheadLevels,andthe
Ancholme and Lower Trent valleys, is
completedand the resultspublishedin three
monographs(Van deNoort & Ellis 1995;1997,
1998). The survey is programmedto be
completedby 2001.
Primary productivity
Biological productivity is usuallydefinedin
termsof biodiversity (speciesrichness)or the
by anecosystem.
amountofbiomassgenerated
Biodiversity is often difficult to quantify and
is not necessarilydirectly linked to biomass
productivity. The latter can be divided into
primary and secondaryproductivity. Primary
productivity is the amount of organic matter
synthesisedby organismsfrom inorganic
sources,thusit usuallycompnsesmainly plant
material. In wetlands,for example,primary
producersincludemacrophyticplantsaswell
asbactena, algaeandplankton.The secondary
productivity of an ecosystemis the amountof
organicmattersynthesisedby organismsfrom
primary producersand their products.
Secondaryproducersincludeall herbivores,
Fig 13 l. A digital terrain/
elevation model of the
Humber wetlands, with
the regions of Holderness
(A) and the Humberhead
Levels (B) indicated.
DTM: DuncanWhyatt1996.
Dinnin & Van de Noort
2s00
3000
3500
e s t u a r i n ea n d b r a c k i s h
t e m p e r a t es w a m p & m a r s h
c u l t i v a t e dl a n d
Fig.I 3.2. The variation
in estimatesof net
primaryproductivity of
differentecosystems
(g/m']/yr)Source; Leith
1975citedin l(illiams
1990;Maltby 1986
Graph:Robert Van de
Noort 1996.
t r o p j c a lr a i n f o r e s t
r a i n g r e e nf o r e s t
s u m m e r g r e e nf o r e s t
warm temp mixed forest
t r o p i c a lg r a s s l a n d
t e m p e r a t el a k e & s t r e a m
borealforest
t e m p e r a l eg r a s s l a n d
tundra
@
M
W
eLF,.WLA
desert scrub
dry desert
tceoesert
all predators and detritivores that feed on
organic matter. Thus, secondaryproducers
rangefrom microscopicinvertebratesto more
complex 'higher order' animals,which in
wetlandsincludeall fish andwildfowl.
The primary productivity of an ecosystem
providesa measureof the amountof energy
availablein the lowestlevel of the food chain.
This energysupportsthe secondaryproducers
and consumershigher up the food chain.From
a human perspective the net primary
productivity of an ecosystemis critical in
determining the quantify of potential natural
resources.Primary producers,namelyplants,
are of direct value as food, construction
materialsand so forth. Althor-rghthervarc of
indirect value in providing grazrng for
exploitable secondaryresource
s (e.g. domestic
stockandwild game),,
greatest
the
food value
comesfrom the food websthatthe deadplants
support(Williams 1990).
The importance of characterisationof
primary productivity in ecosystems
characterisation
hasresultedin many attempts
to providequantitativeassessments
to enable
both inter and intra-ecosystem
comparisons.
Assessmentshave been based mainly on
sequential harvesting of vegetation,
measurementsof plant density/heightand
measuredrateof photosynthesis or respiration
(e.g.Bradbury& Grace1983).The former is
the most widely usedestimatetechniqueand
is expressedin termsof massof produceper
unit areaper unit of time. Producemassmay
be determinedasdry weight or ashedweight.
Although attemptshavebeenmadeto quantifli
secondaryproductivity, methodological
difficultieshaveusuallyrestrictedsuchstudies
to analysesof partrculartaxonomicor ecological
groups,usuallyinvertebratesor fish (e.g.Orth
et a|.1991;Petersen
et a\.1995).Themajority
of studiesprovideonly qualitativeassessments
of secondaryproductivity. The methodological
difficultiesandinconsistencies,
togetherwith
thevariability of edaphicconditionsexplainthe
broadrangeof estimatedprimary productivity
for different ecosystemscited in fig.13.2.
Nonetheless,they indicatethat wetlandsare
asproductiveor in somecasesmoreproductive
than many ecologically 'rich' terrestrial
ecosystems
(e.9.Whighamet al.I978;Maltby
1986).The high productivity of wetlandsis
generallyattributedto the plentiful supply of
nutrients, due to flushing with nutrient-rich
water, and low water stressfor most of the
year (Long & Mason 1983;Mitsch &
Gosselink1993).
Primaryproductivity in wetlandsis largely
controlledby the amountof nutnentsavailable
to primary producersover a period of time
(Thomson& Hamilton 1983).Furthermore,
the degree to which primary products are
convertedto forms useableby secondary
producersis a significant factor in determining
the nature and complexity of the food web.
Wetlandsare characterisedby the water table
usuallybeing aboveor closeto the surfaceof
the substrateinto which vegetationis rooted.
This generallyinhibits therateat which pnmary
and secondaryproducts are decomposed.
Where the rate of supply of dead material
derivedfrom primary and secondaryproducers
exceedsthe rate of decomposition,organic
materialmay accumulate(Bradbury & Grace
1983).The nutrients within undecomposed
organicmaterialareeffectivelyunavailableto
the food web until, for example,a lowering of
the water tablebrings them within the aerated
and bioturbatedzone.It is variationsin the
rateof nutrientavailabilitythat largelyexplain
the dif ferencesin primary productivity between
wetlandecosystems
which, in turn, determines
their resourcepotential.
Dinnin & Van de Noort
Dominant soecies/classifi
cation
Mire (peat-producing) ecosystems
Oligotrophic
Calluna vulgaris blanket bog
Calluna vulgaris-Eriophorum vaginatum blanket bog
E riop horum-Sphagnum blanket bog
E riop horum-Sphagnum blanket bog
Non wooded raisedboe
Wooded raisedbog
Pinus-Sphagnumbog
String bog
Conifers/bryophytes
EricaceousShrubs/sedges/bryophytes
Ericaceousshrubs,/bryophytes
Ericaceousshrubs,bryophytes/conifers
Ericaceousshrubs/sedges
EricaceousShrubs/sedges/bryophytes
EricaceousShrubs/sedges/bryophyes
SaI ix I Car ex/bryophyte s
Sedgemeadow
Mesotrophic
Transition Pinus-Sphagnumbog
Transitionforestbos
Minerotrophic
Alnus & Fraxinus
A I isim,ap Iantago-aquatica
Carex spp.
Carex spp.
Glyceria maxima
Glyceria maxima
Nuphar spp.
Phragmites ausftalis
Phragmites austalis
SchoenopIectus I acustris
Scirpus lacustris
Typha spp.
Chamaedaphne-B etula rich fen
Swamp
Fen forest
Lotic ecosystems
All organic material
Periphyton
Benthic diatoms
Macrophyte plants (Ranunculusspp.)
Phytoplankton
Phytoplankton
Brackish and estuarine ecosvstems
Limonium
Salicornia
Saltmarsh
Zostera
Spartina
ina
Location
Northern England
Northern England
Scotland
Ireland
Western Europe
Westem Europe
Russia
Karelia,Russia
Manitoba,USA
West Siberia,Russia
Manitoba,USA
Manitoba,USA
Ireland
Central England
North Wales
Norway
N. Sweden& N. Norway
Russia
Michigan USA
Central Alberta Canada
N.W. Europe
New York StateUSA
SouthernEngland
Czechoslovakia
Midwest, USA
Denmark
Britain
Czechoslovakia
N.W. Europe
Michigan, USA
USSR
Minnesota
W. USA
W. USA
R. Lomme, W. Europe
R. Virion, W. Europe
R. Meuse,W. Europe
R. Loire, W. Europe
U.K.
N.W.Europe
N.W.Europe
Mid-Atlanticcoast,USA
N.W. Europe
Mid-Atlanticcoast,USA
Productivity (g m-' vear-')
177-272
364-768
741
316-341
400-500
340
260
440-600
523
210-450
482
399
338
438
857
3s9- 835
136-163
393
350
570-640
444
337-630
l 034-l 580
660-1237
900-4300
863-780
781-1400
55I -2500
I 600-5500
4600
956-2900
341
720-780
651
80-900*
t24-358*
140,r.
310*
490-550+
750'r'
1050
200-1000
800-I 200
r06-2040
572-4500
1760-4490
Fig 13.3. Estimatedprimary productivity of wetland ecosystems.Sources:Billen et al.l995; Botch & Masing 1983; Bradbury
&Grace 1983;Fisher 1995;Ladle&Westlake1995;Long&Mason 1983;Maltby1986;McLusl<y1977;Mitsch&Gosselink
1993; Oswood et al.l995; Reader 1978; Whigham et al.l978; I{illiams 1990. NB valuesfor lotic (river) ecosystemsarefor
primary productivity of spectfied organisms rather than net. * denotesproductivity given as ashed dry weight.
72
Dinnin & Van de Noort
Primary productivity
and resourcepotential
In general, primary productivity and plant
speciesdiversity in wetlandsincreaseswith
flowthrough conditions(Mitsch & Gosselink
1993). Thus, fens are more productive than
stagnantraisedmires, andnon-flowing or deep
water wetlands (e.g. deep lakes or forest
swamps)are lessproductive than flowing or
periodically inundatedwetlands(e.g. riversand
floodplainforest;fig.13.3).This is because
flowthrough provides a flush of nutrients,
episodic inundation reducesanaerobic
conditionsandresultsin increasedecological
heterogeneity (opt.cit.) . Thus, ombrotrophic
(rain-fed), oli gotrophic(nuhient-poor)raised
bog and blanket bog are among the least
productivetypesof wetlandbecausetheyhave
little allochthonousnutrientinput. Only a small
rangeof specialistplants,mainly Sphagnum
mosses,cantoleratethe high watertable,low
nutrient availability and low pH of these
environments.Thesefactors,togetherwith low
temperatures mean that the rate of
decompositionis typically exceededby net
primary productionof, for example,Sphagnum
mossesor ericaceousshrubs.This resultsin
peataccumulationwhich actsasa nutrientsink,
reducing nutrient availability to organisms
higher up the food chain. Consequently,a
relatively low biomassof invertebrate
herbivores and in particular vertebrate
herbivoresis found in temperateoligohophic
bogs. The few vertebrateherbivoresthat do
occur areableto utilise only a smallproportion
of the plant material (primary produce).The
dearth of vertebrate herbivores means that
carnivores are also scarce(Long & Mason
1983). The acidity of raised mire waters
precludesfish.
The relatively low productivity and
specificdiversityof oligotrophicbogsmeans
that they canprovideonly a limited numberof
specialisednatural resourcesexploited by
humans.TheseincludeCalluna vulgaris,used
for bedding or dyeing,,edible fruits of
Vaccinium oxycoccus or Myrica gale for
flavouring. Eriophorum-Calluna bog
vegetationmay provide a useful resourcefor
gr azingstock where availability of othermore
nutritious vegetation is limited (Caseldine
1988).It is pertinentto note that in northern
and central Europe a traditional method for
bringing raisedbogs into cultivation was to
loosen the upper layer of peat and then burn
thedry material.Theresultingreleaseof stored
nutrientswas sufficient for meagrecerealcrops
or grassfor grazingto be grown for up to 7-10
years,after which exhaustionnecessitateda
30 year fallow period(Heathwaiteet al.I993).
In contrast,minerotrophic (nutrient-rich)
fens have a high productivity (fig.13.3) and
receive nutrient supplies from groundwater
and,inriver floodplain situations,floodwater.
Although peataccumulationmay removesome
nutrientsfrom the ecosystem,nutrient supply
rateis usuallysufficientto ensurehighprimary
productivity.It is only when peataccumulation
resultsin decreasedgroundwaterinfluencethat
oligotrophicbog may developautogenically
from minerotrophicfen (Godwin 1975).The
primary productivity in minerotrophic fensis
oftencomparableor in excessof that observed
in adjacent agricultural land (e.g. Long &
Mason 1983).Nutrient flushing andmoderate
to high pH enablesthe developmentof complex
secondaryproducercommunitiesthat usually
include fish as well as wildfowl. In general,
the deeperthe water andmore openthe system
is to large rivers or lakes,the more abundant
thevanetyof fish (Mitsch & Gosselink1993).
Floodplain fensareparticularly productiveand
biodiversebecausethey form structurally
complex ecotonesbetween dryland and
riverine ecological units (opt.cil). Thus,
although a particular plant speciessuch as
Phragmites may dominate a swamp, higher
orderanimalssuchasbirds areableto utilise a
rangeof habitatswithin the wetland-dryland
ecotone(Long & Mason 1983).
Similarly,riparian(river and stream-side)
habitats are particularly species-richand
biologically productive(fig.13.3).This is
becausepulse flooding provides water for
growth, a supply of nutrients and favourable
soil aerationconditions(Long & Mason 1983;
Mitsch & Gosselink1993).Although estimation
of primary productivity in riparianecosystems
is particularly difficult (e.g. becauseof
anthropogenicmodifications),the'River
ContinuumConcept'dictatesthat in general,
the number andtype of primary and secondary
producersand productivity tends to increase
downstreamand with increasedstreamorder,
and this is supportedby empirical evidence
(see Cushing et al.I995 and references
therein).This is becausethere is a general
increasein river surfaceareafree from shading
andincreasednutrientsupply rnadownstream
direction, leading to, for example, both
73
Dinnin & Van de Noort
increasedfish productivity and diversity
(Cumminset a|.1995;Fisher 1995;Mackay
1995).The corollary of this is of coursean
increasedquantity and diversity of natural
resourcesfor humanexploitation.
The downstreamtrend in increased
productivity extendsinto estuaries,which are
among the most productive ecosystemson
earth(fig. 13.3).Saltwateror brackishwetlands
subjectto frequent tidal action are generally
moreproductivethan lessfrequentlyinundated
areas(Mitsch & Gosselink1993).The regular
influx of nutrient rich detrital mud supportsa
vast quantity of primary producers.Although
relatively little of this may actually be
consumeddirectly by animals,decayingplant
fragmentsform a substantialproportionof the
detrital mud that supportsextremely large and
complex foods webs (Mclusky 1977).The
high primary productivity of saltmarshesis
mirroredby secondaryproductivity,including
annelids,molluscs,crabs,shrimpsand fish,
supportingprodigiousnumbersof higher order
feeders,namely wildfowl which may reach
densitiesof 216 birds per km2 comparedto
only threeover openwater (Williams 1990).
Whigham et al. ( 1978) suggestthat freshwater
tidal wetlands, i.e. the lower reachesof tidal
rivers,may be evenmore productivebecause
theybenefit from nutrientreplenishmentfrom
tidal flushingwhile avoidingsalinestress.
The foregoingdiscussionindicatesnot only
thatpnmaryproduchvitymay be usedto idenhfy
vanationsbetweenthe ecologrcalproductivityof
different wetland ecosystems,but also that it
providesa measureof their resourcepotential.
There is a general pattern of increased
productivity and species-richness
progressing
from oligotrophic interior wetlands towards
npanan-riverine margins, and from lower to
higher order streamsculminatingin estuarine
ecosystemsat the interface between the
freshwaterandmarineenvironment.In termsof
primary productivity andspeciesrichness in the
Humber wetlands, prior to their large scale
drainage(which can increasespeciesrichness,
for exampleasattestedfor theraisedbogsin the
HumberheadLevels),the richestareaswerethe
Humber estuary and the lower reachesof the
main rivers (e.g. Hull, Trent and Ancholme),
while the oligotrophic mires could be
characterisedas the poorest.For the present
discussion,theproductivity andspeciesrichness
ofthe wetlandsin the regionsof Holdernessand
the HumberheadLevels can be ranked, from
low to high, asthus:
74
- oligotrophicecosystems(raisedbogs)in the
HumberheadLevels
- isolatedopen water ecosystems(lakes or
meres)in Holderness
- open water ecosystems(lakes or meres)
connected
to largernversystemsin Holdemess
- minerotrophicecosystems
in river floodplains
in the HumberheadLevels
- riparian ecosystemsin the Humberhead
Levels
- b r a c k i s h o r e s t u a r i n ee c o s y s t e m si n
Holderness.
Resourcepotential and exploitation
The assessmentof the exploitation of the
resourcepotentialofthe wetlandsin theregions
of Holdernessandthe HumberheadLevelsis
largely basedon the distribution of flint and
pottery scattersfound during survey, aerial
photographic analysis and ten small-scale
excavationsundertakenbetween 1994 and
1996aspart of the Humber WetlandsSurvey
(Van de Noort & Ellis 1995;1997).Although
it is imperativeto stressthat not all sitesand
finds arerelatedto exploitationfor reasonsof
subsistence,
the largenumberof find locations
(>1100) which form the basis of this
assessmentundoubtedly reflects general
patternsof occupationand exploitation.The
surveyundertakessystematicfield walking in
'mapviews'
each4x5 km in size,andcentred
on a wetland.Therefore,not only the wetlands
but also extensiveparts of the surrounding
'drylands'
in an identicalmanner,
areassessed
while the integrated coring programme
identifiesareasof buriedlandscapes.
Summarising the main results in
chronological order, three flint scatters
including pieces diagnostic for the Early
Mesolithic were found in the Humberhead
Levels on slightly elevatedlocations
immediatelyadjacentto nvers, while a fourth
site,datedto this periodby radiocarbonassay
of a singlealderpeg,was found in oneof the
most extensivemere-complexeswhich is
connectedto the River Hull, in Holderness
(Head et al.l995a;1997a). No finds or find
scattersdatedto the Early Mesolithic were
found elsewhere.Sitesand finds datedto the
LateMesolithicandEarlyNeolithicperiodwere
found in similar contextsin both regions,but
also in southernHoldernesswhere brackish
wetlandsdevelopedin the lowlands adjacent
to the Humber estuaryaround 3800 cal.BC
(c.5000BP),a development
closelyassociated
-\
'I
i
Dinnin & Van de Noort
to sea-levelrise (Dinnin& Lillie 1995;Head
et al.\995a; 1995b; 1997a;1997b).Based
solelyon flint assemblage
characteristics
from
the HumberheadLevels, it has been argued
that thesesitesreflectpossibleseasonalrather
than permanentoccupation(Head 1997).The
very close spatialassociationof finds, finr;
scattersand sitesof the earlierHolocenewiti
nutrientrich wetlands(rivers,Iakes connecter
to rivers and brackish/estuarinewetlands,
suggestsa specialisedexploitationof thesc:
habitats,most likely focusedon fishing and
hunting of wild fowl. The completeabsence
of sitesof this period at and aroundnutrient
poor wetlandssuggestthat for specialised
wetlandexploitationdunngtheMesolithicand
Early Neolithic, only the richest wetlands
sufficed.
In the laterNeolithicandEarly BronzeAge
the distancebetweenarchaeological
sitesand
their nearestwetlandincreased(Head 1997).
Findsdatedto thisperiodhavebeendiscovered
on the floodplainsof all therivers andadjacent
to the brackish wetlands in southern
Holderness.Low concentrationsof artefactual
materialwerealsofoundnearall meres,both
isolatedandconnectedto largerriver systems,
in Holderness(Headet a|.1995).The spatial
associationbetweensitesof this period and
the wetlands is still clear, but the distance
varies.This is partly dueto widespreadwetiand
developmentin the HumberheadLevels as a
consequence
of the continuedsea-levelrise.
Wetland developmentwas causedthrough
paludificationandoverbankflooding alongside
the rivers,which madethe mostnutrientrich
wetlands(i.e. therivers andtheir minerotrophic
floodplainmires)poorly accessible
asa result
of the developmentof mesotrophicfen and
mire on the floodplainmargins.However,the
importanceof agricultureincreaseddunngthis
period, and the reducedinterestin wetlands
andtheir resourcemay well be a reflectionof
the changingmode of subsistence.
The new
associationof sites with the nutrient poor
wetlands,in particularthe isolatedlakes in
H o l d e r n e s s ,m a y r e f l e c t t h e i n c r e a s e d
importance of year-roundwater supply in a
pastoral-dominated
economy.
From the Middle BronzeAge onwards,and
particularly during the Late Bronze Age and
Early Iron Age, very few archaeological
sites
appear in or near the wetlands of the
HumberheadLevelsandHolderness.A short
trackwayof Late BronzeAge date,discovered
on ThorneMoors (one of the raisedmires in
the HumberheadLevels) during peatextraction
in the 1970s,is the main exception(Buckland
& Kenward 1973),but this may have been
built to allow accessto nearbydryland areas
rather than for wetland exploitation (Dinnin
1997b).However,high densitiesof artefactual
materialandaerialphotographicevidencefor
humanactivity in this period havebeenfound
on the higher, free draining soils surrounding
the wetlandsin the Humber lowlands.This
illustratestheemphasison farming,withpollen
analysissuggestingthe increasedimportance
of arablerather than pasture(Smith 1985;
Taylor 1995).
In the HumberheadLc:.zels,but not in
Holderness,this picture changesagarnafter
the Roman conquestof the area.Throughout
thisregionwe seeRomansettlementsappeanng
in the later third and fourth centuries AD
(fig.13.4).The distributionof sitesof this date
appearslargely unrelatedto the wetlandsin
generalor to specifictypes of wetlands,and
no associationexists betweenthis phaseof
settlementandbiological productivity of the
wetlands.Rather it appearsthat a temporary
sea-levelregression providedopportunitiesfor
agriculturalexpansioninto the wetland areas,
and Roman settlementappearsto have taken
place in the HumberheadLevels even on
humified peat. The existenceof an urban
economy and increased demand for
agriculturalproductsmay alsohaveprovided
additionalfactorsin the possibly short-term
but widespreadexploitationof the lowlands
aroundthe Humber.
No archaeological
finds of Early Medieval
date can be related to the wetlands of
Holdernessor the HumberheadLevels.In the
thirteenthand fourteenthcenturies.however.
it appearsthat previously unoccupiedareas
within theHumberheadLevelswereinhabited,
with farms and grangessurroundedby moats
(Fenwick 1997).The late and post Medieval
exploitationof wetlandsis recordedin written
sources,and the l Tth century decoyson the
raisedmires of the HumberheadLevels and
on the marginsof otherwetlandsillustratethe
exploitationof wildfowl. However,by thisdate,
the role of the wetlandsin the economywas
not more than marginal,and the majority of
wetlandswere drained from the early 17th
centuryonwards,to provide arableland.
75
F
Dinnin & Van de Noort
Conclusion
Wetlands are amongst the most productive
environmentsin the world, and although the
generalvalidity of this statementis correct,
the detailedexaminationofthe environmental
history of the wetlands and the identification
of archaeologicalsites associatedwith the
wetlandsin the regionsof Holdernessandthe
HumberheadLevels have identified important
highlightsandexceptionsto their significance
andexploitationin the past.Theseincludean
awarenessthat the differenttypesof wetlands
in the region were attributeddifferent values
in different archaeologicalperiods. The
changing modes of subsistence and
environmentaldevelopmentof the wetlands
during the Holocene, in particular as a
of sea-levelchange,appearto
consequence
form the most important elements in this
changingperceptionof the Humberwetlands.
Fig.l3.4. An aerial photograph of the late Roman settlementat Scaftworthin the ldlefloodplain, Humberhead
Levels. RCHME Crown C.opyright.Photo Derek Riley 1976-
76
Dinnin & Van de Noort
References
Billen, G., Dechamps,
H., Garnier,J.,BoetP.,Meybeck,
M. & Servais,P. 1995: Atlantic river systemsof
Europe(France,Belgium,the Netherlands).In: C.E.
Cushing,K.W. Cummins& G.W. Minshall (eds)River
and stream ecosystems,Ecosystemsof the world
22, 389418. Oxford: Elsevier.
Botch,M.S. & Masing,V.V. 1983:Mire ecosystems
in
the U.S.S.R.In: A.J.P. Gore (ed.) Mires; swamp,
bog, fen and moor; regional studies, Ecosystems
of theworld 48, 95-152.Oxford:Elsevier.
Bradbury,I.K. & Grace,J. 1983:Primaryproductionin
wetlands.In: A.J.P. Preece(ed.): Mires; swemp,
bog,fen and moor, Ecosystemsof the world 44,
285-310. Oxford: Elsevier.
Brown, A.V. &Matthews, W,J. 1995:Streamecosystems
ofthe westernUnited States.In: C.E. Cushing,K.W.
Cummins & G.W. Minshall (eds)River and stream
ecosystems,Ecosystemsof the world 22, 89-116.
Oxford: Elsevier.
Buckland,P.C. & Kenward,H.K. 1973:ThorneMoor,
the palaeoecologicalimplications of a Late Bronze
Age site.Nature24I ,405.
Caseldine,A. 1988:A wetlandresource:the evidence
for environmentalexploitationin the SomersetLevels
during the prehistoricperiod. In: P. Murphy & C.
French (eds) The exp Ioi tati on of wetl ands, 239 -265.
British ArchaeologicalReportsB I 86.
Cataneo,A., Salmoiraghi,G. &Gazzera, S. 1995:The
rivers of ltaly. In: C.E. Cushing,K.W. Cummins&
G.W. Minshall (eds)River and stream ecosystems,
Ecosystemsof the world 22.389-418. Oxford:
Coles, B. & Coles, J. 1989: People of the wetlands.
Bogs, bodies and lake-dwellers.London: Thames
andHudson.
Cummins,K.W., Cushing,C.E.& G.W. Minshall 1995:
Introduction:an overview of streamecosystems.
In:
C.E.Cushing,K.W. Cummins& G.W. Minshall(eds)
River and stream ecosystems,Ecosystemsof the
world 22,1-8.Oxford:Elsevier.
Cushing,C.E.,Cummins,K.W. & G.W. Minshall (eds)
1995:River and streamecosystems,
Ecosystemsof
the world 22. Oxford: Elsevier.
Denny, P. 1995: Benefits and priorities for wetland
c o n s e r v a t i o n :t h e c a s e f o r n a t i o n a l w e t l a n d
conservationstrategies.
In: M.Cox, V. Straker& D.
Taylor (eds) LYetlands.Archaeology and nature
conservatio n, 249-274. London: HMSO.
Dinnin, M. 1997a: The drainagehistory of the
HumberheadLevels.In: Van deNoort. R. & Ellis. S.
(eds)1997,l9-30.
Dinnin, M. 1997b:The palaeoenvironmental
surveyof
West,Thome andHatfield Moors. In: Van deNoort,
R. & Ellis,S. (eds)1997,157-189.
Dinnin, M. & Lillie, M. 1995:Thepalaeoenvironmental
surveyof southemHoldernessandevidencefor sealevel change.In: Van de Noort, R. & Ellis, S. (eds)
1995.87-t20.
Fenwick, H. 1997:The wetlandpotentialof Medieval
settlementsin the HumberheadLevels.In: Van de
Noort, R. & Ellis, S. (eds)1997,429-438.
Fisher,S.G. 1995: Streamecosystemsof the Western
United States.In: C.E. Cushing,K.W. Cummins&
G.W. Minshall (eds)River and streamecosystems,
Ecosvstems
of theworld 22.61-87. Oxford: Elsevier.
Gaunt,G.D. & Tooley,M.J. I 973: Evidencefor Flandrian
sea-levelchangesin the Humberestuaryandadjacent
areas.Bulletin of the Geological Survey of Great
Britain 48,25-41.
Godwin, H. 1975: The history of the British flora.
Cambridge:CambridgeUniversity Press.
Head, R. 1997:The use of lithics in the Humberhead
Levelsin prehistory.In: Van de Noort, R. & Ellis, S.
( e d s )1 9 9 7 , 3 8 3 - 3 9 5 .
Head,R., Fenwick,H., Van de Noort, R., Dinnin, M. &
Lillie, M. 1995a:The meresand coastalsurvey.In:
Van de Noort, R. & Ellis, S. (eds)1995,I 63-239.
Head,R., Fenwick,H., Van de Noort, R., Dinnin, M. &
Lillie, M. 1995b:The surveyof southemHolderness.
In: Van de Noort,R. & Ellis, S. (eds)1995,241-310.
Head,R., Fenwick,H., Chapman,H., Van de Noort, R.,
& Lillie, M. 1997a The archaeologicalsurveyofthe
Rivers Aire, Went, former Turnbridge Dike (Don
north branch) and the Hampole Beck. In: Van de
Noort,R. & Ellis, S. (eds)1997,229-264.
Head,R., Fenwick,H., Chapman,H., Van de Noort, R.
& Dinnin, M. 1997b:The archaeologicalsurveyof
the Riversldle, Torne andOld River Don. In: Van de
Noort, R. & Ellis, S. (eds)1997,267-367.
Heathwaite,A.L.Gottlich, K. & Cooke,J. (eds)1993:
Mires; processes,exploitation and conservation.
Chichester:Wiley.
Jones,R.L. & Gaunt,G.D 1976:A datedLateDevensian
organicdepositat Cawood,near Selby.Naturalist,
H u l l 9 3 9 ,l 2 l - 1 2 4 .
ladle, M. & Westlake,D.F. I 995:River andstreamecosystems
of GreatBritain.In: C.E.Ctshing,K. W. Cunmins & G.W.
Minshall (ds) River and gream ecosystems,
Ecosystems
oftheworld 22,343-388.Oxford:Elsevier.
Long,S.P.& Mason,C.F. I983: Saltmarshecologt.New
York: Chapman& Hall.
Mackay, R.J. 1995: River and streamecosystemsof
Canada.In: C.E. Cushing,K.W. Cummins& G.W.
Minshall (eds) Riuer and stream ecosystems,
Ecosystems
of theworld 22, 33-60. Oxford: El sevier.
Maltby, E. 1986: I(aterlogged wealth; why waste the
world's wetplaces? London: Earthscan.
Mitsch, W.J. & J.G. Gosselink 1993: Wetlands.2nd
edition.New York: Van NostrandReinhold.
Mclusky, D.S. 1977:Theestuarineecosystem.
London:
Blackie.
Orth,R.J.,Heck, K.L. & Diaz, R.J. l99l: Littoral and
intertidal systemsin the mid-Atlantic coast of the
United States.In: A.C. Mathieson& P.H. Nienhuis
(eds)Intertidal and littoral ecosystems,Ecosystems
ofthe world 24,193-214.Oxford: Elsevier.
Oswood,M.W.,lrons,J.G.& Milner,A.M. 1995:River
and streamecosystemsof Alaska. In: C.E. Cushing,
K.W. Cummins & G.W. Minshall (eds)River and
stream ecosystems,Ecosystemsof the world 22,932.Oxford:Elsevier.
Parkes,A. 1996: Holocene evolution of the Humber
estuary:a Land-Ocean-Evolution-Perspective-Study
(LOEPS). ln: Second Annual Report Humber
WetlandsSurvey(1995-96), 17-19.Hull: Humber
WetlandsProject,University of Hull.
Petersen,
R.C.,Gislason,G.M. & Vought,L.B.-M. 1995:
Riversofthe Nordic countries.In: C.E. Cushing,K.W.
Cummins& G.W. Minshall (eds)River and stream
ecosystems,
Ecosystemsof the world 22,295-342.
Oxford: Elsevier.
77
Dinnin & Van de Noort
Pethick,J.S. 1990:The Humber Estuary.In S. Ellis &
D.R Crowther (eds)Humber Perspectives:a region
throughtheages,54-70.Hull: Hull UniversityPress.
Reader,R.J. 1978:Primary productionin northernbog
marshes.In: R.E. Good, D.F. Whigham & R.L.
Simpson (eds) Freshwater wetlands: ecological
processes and managementpotential, 53-62.
London:AcademicPress.
Sheppard,J.A. 1956: The draining of the marshlands
of East Yorkshire.PhD thesis,University of Hull.
Smith, B.M. I 985: A palaeoecological study of raised
mires in the Humberhead Levels. PhD thesis.
Universityof Wales.
In: A.J.P.
Speigh!M.C.D.& Blackith,R.E. I 983:Theanirnals.
Preece 1983: Mires; swamp, bog, fen and moor,
Ecoqystems
ofthe world 4A,349-365.Oxford:Elsevier.
Taylor, D. 1995:New pollen datafrom the Keyingham
valley,southernHolderness.In: Van deNoort, R. &
Ellis,S.(eds)1995,121-127.
Thompson,K. & Hamilton, A.C. 1983: Peatlandsand
swampsof the African continent.In A.J.P.Gore(ed.)
Mires: swamp, bog, fen and moor: regional
studies.Ecosystemsof the world 48, 331-313.
Oxford: Elsevier.
78
Van de Noort, R. & Davies,P. 1993:Wetlandheritage.An
of the Humber wetlands.
archaeologicalassessment
Hull: HumberWetlandsProjectUniversityofHull.
Van deNoort, R. & Ellis, S. (eds)1995:Wetlandheritage
of Holderness. An archaeological survey. Hull:
HumberWetlandsProject,Universityof Hull.
Van deNoort,R. & Ellis, S.(eds)1997:lktland heritageof
the HumberheadLevels.An archaeological survey.
Hull: HumberWetlandsProjectUniversityofHull.
heritage
Van deNoort, R. & Ellis, S. (eds)1998:Ll/etland
of the Ancholme and Lower Trent valleys. Hull:
HumberWetlandsProject,Universityof Hull.
Van de Noort, R. & Ett6,J. 1995:The HumberWetlands
Survey: background,objectivesandmethodology.In :
Van de Noort, R. & Ellis, S. (eds)1995,l-7 .
Whigham,D.F., McComerick,J., Good, R.E. & R.L.
Simpson 1978:Biomassand primary productionin
freshwatertidalwetlandsofthe Middle Atlantic Coast.
In R.E. Good,D.F. Whigham & R.L. Simpson(eds)
Freshwater wetlands: ecological processes and
managementpotential,2-20. l,ondon:AcademicPress.
Williams, M. 1990: Understandingwetlands.In M.
Williams (ed.) Wetlands,a threatenedlandscape,
1-41. Oxford: Blackwell.