Climate and Environmental Change on Dartmoor: lessons from archaeology and palaeoecology

by Ralph Fyfe (Newsletter 31, pp11–17) – 7th November 2007.

Inaugural Research Lecture Climatic and Environmental Change on Dartmoor: Lessons from Archaeology and Palaeoecology’. Dr Ralph Fyfe

From Newsletter 31: November 2007

Around 90 people attended our inaugural Research Lecture on Th November

2007 at the University of Plymouth. Dr Ralph Fyfe, Senior Lecturer of the

University’s Department of Geography, gave an excellent presentation of his

paper ‘Climatic and Environmental Change on Dartmoor: Lessons from

Archaeology and Palaeoecology’. The Lecture was used to promote the

Society’s Research Fund and we are very grateful to the Dartmoor National

Park Authority for contributing £1 50 towards the cost of this event.

Dr Fyfe began by summarising the role of the environmental archaeologist,

which is [1] the analysis of environmental samples in association with cultural

landscapes or archaeological sites; and 121 the reconstruction of past

environmental conditions, landscapes, subsistence strategies and so on.

Unlike ‘mainstream’ archaeology, the work of the environmental archaeologist

involves very 4ittle excavation.

Ralph explained that his primary research interests are in the dynamic and

changing relationship between society and environment, in particular in prehistory,

and in particular, the balance between human impact on the environment, and the

impact of the environment on humans. H e has been carrying out research on

Dartmoor [Shovel Down Project, Cut Hill and Whitehorse Hill project, upland

peatland survey work] since 2003 and on other uplands [e.g. Exmoor, Preseli

Hills, Snowdonia’ since 1997.

Why study uplands [and Dartmoor in particular]?

Ralph said that there are three primary attractions for environmental

archaeologists in studying uplands. Today we consider these to be marginal

environments; they might therefore be more sensitive indicators of the

dynamic between nature and society. The archaeological landscapes of

uplands may typically be preserved better than in corresponding lowland

areas, and they are more likely to include, and preserve, high

potential environmental sequences in juxtaposition with archaeological sites

Of the uplands in the UK, Dartmoor offers a range of exciting opportunities.

The degree of preservation and visibility of the archaeology makes Dartmoor

one of the flagship prehistoric archaeological landscapes in the UK.

Dartmoor has a strong legacy of archaeological research ‘at least in some

periods and excavation which provides baseline archaeological models.

There is an abundance of potential palaeoecological and environmental

resources across the upland. It is a landscape which is perceived through

modern eyes as very marginal for agrarian activities. Dartmoor has a very

supportive National Park Authority!

 

However, there are pitfalls to working in upland areas• they may not be

“typical” places in prehistory…the main focus of activities may have been

elsewhere which may result in a biased or poor understanding of relationships

in the past if we only rely on these areas. The environmental sequences [i.e.

physical characteristics of the past environment that can be inferred from the

underlying soils] may be abundant, but their upland location may not make

them sensitive to subtle societal changes and re-organisation. Finally, they

are palimpsest landscapes [i.e. those on which the traces of earlier activity

have been destroyed by later activity]; this may be a curse as well as a

blessing. Ralph said that a prime example was the impact of what he called

the tiresome medieval tinners!

Ralph’s talk focused on four key themes:

[ I ] The notion of Dartmoor as marginal in the past;

121 The changing environment in prehistory;

131 The key periods of archaeological and landscape change between the

Mesolithic and the late Bronze Age; and

141 A discussion of nature/society balances through time.

Dartmoor and the “margin”

Modern margins are based on economic concerns [inputs vs. outputs in an

agrarian system] within a productionist system, but how much relevance does

this have to prehistory? The traditional archaeological view of upland

marginality is based on the population resource model. Uplands are physically

marginal for agriculture li.e• poor soils, unsuitable climatic conditions’ with

the ‘margins’ only exploited during population expansion ‘crises’. Dartmoor

is at the physical margins, having high average rainfall of between 1381 —

2584mm per year, only 1348 — 1500 hours of sunshine per year and between

97 and 114 days of ground frost per year INB all figures based on 30 year

averages, 1971 — 2000].

Marginality as a concept is not, however, limited to the environment, and

other factors can cause marginality, or make an area more attractive. These

include the non-agrarian resource in the uplands; the dynamic nature of the

physical environment; cultural controls on margins [the locations of zones of

production and consumption]; the prevailing political and social constraints

on access to space; and variations in the importance of all of the above

through time!

 

Certain palaeoecological techniques can be applied to reconstruct

landscape and climatic change, and four main types have been applied on

Dartmoor: pollen analysis, proxy climate reconstruction (from testate

amoebae], charcoal analysis and fungal spore analysis. Pollen analysis is the

inspection, identification and counting of the pollen from different plant

species present in an environmental sample. Climate reconstruction is

usually undertaken from peatland systems using proxies of water table height

[e.g. zonation of microorganisms such as testate amoebae]. Each species has

a distinct ecological niche on bogs relating to water table height, which

reflects prevailing [summer] climatic conditions. If a reconstructed water

table is high, this indicates a cooler and wet [summer] climate. Conversely, a

low water table indicates a drier and warm [summer] climate. Charcoal

analysis is a proxy for environmental manipulation and land management

practices using fire. Fungal analysis is a novel technique in which analysis of

the presence of certain types of fungal spore can be used to indicate specific

land management -practices [e.g. finding Sporomiella in samples indicates

grazing].

Archaeological methods are used to reconstruct intensity of land use, and

evidence of occupation marking variations in the ‘high tide’ of settlement on

the upland. Typical methods include excavation [this is fairly limited on

Dartmoor with the clearest focus on the Bronze Age], surface survey

!opportunities for field walking tend to be limited owing to limited ploughing],

extrapolation from other uplands and lowland areas Ito date monument

types; this may not necessarily be representative] and landscape change

through on-site palaeoenvironmental analysis.

First monumental use of uplands

Excavation and recent reinterpretation of chronologies by archaeologists at

Cardiff University has shown that upland enclosure [and settlement?] in the

south west first took place at Heiman Tor [near Bodminl around 3845-3650

cal BC and at Cam Brea [near Redruthl at 3885-3505 cal BC. ‘Cal BC’ refers to

the fact that the radiocarbon dating has been calibrated according to the

variation of carbon 14 in the atmosphere at various times in the past.

Lowland enclosures occurred possibly a little later: Hembury [East Devon) at

3715-3575 cal BC and Raddon [Crediton] at 3670-3535 cal BC.

Monument construction also gives an indication of the use of uplands in

prehistory [although monuments only began to be built in North West Europe

in the Neolithic period]. The Cut Hill stone- row [Dartmoor) is one of the

earliest, with provisional dates of construction around 3700-3540 cal BC.

More broadly a recent review of the archaeology of the Neolithic in the

Southwest as a whole [by Josh Pollard, Bristol Universityl has suggested two

main phases of monument construction in the Southwest: 3650-3400 cal BC

and 2600-2200 cal BC.

 

On Dartmoor over 5,000 buildings have been recognised which broadly date

to later prehistory; some of these lie up to 550 metres above sea level. In the

same period, there was widespread establishment of field systems on the

upland. Andrew Fleming undertook extensive. survey of these Dartmoor field

systems in the 1970s and 1980s and developed a broad model for their use.

He suggests they were laid out between 1700 cal BC and lasted for around

300-400 years, with a subsequent abandonment of the upland until the mid-

late Iron Age.

 

Did the environment shape society?

Proxy climate work on Dartmoor is still limited, although recent work from Tor

Royal has developed a better understanding of the past climate. We can look

further to comparable work in upland Britain, which suggests that Neolithic

climates were varied, although evidence is still sparse for this period. The

Bronze Age climate is better understood: it is marked by various fluctuations:

drier summers were dominant around 1700 cal BC, 1200 cal BC and 900 cal

BC, with intervening periods wetter. When considering how this climatic

chronology fits with the archaeology, we do come up against problems,

mostly over how well we believe or understand the chronology of the

archaeology.

Analysis of environmental conditions at monuments and landscapes in the

Neolithic period at the Cut Hill Stone Row [above 600 metres above sea level]

on northern Dartmoor has shown the following:-

 

The graphs below show the percentages of five vegetation types found in the

peat at various depths land hence periods in the past] at Cut Hill. The vertical

[left hand] axis represents the depth of the peat (range 0 to 190cml, which is

a proxy for time period, as the peat has been gradually laid down over past

millennia. The horizontal !top’ axis represents the amount of species pollen

as a percentage of the whole sample. (Editor’s note: as the horizontal scales

are rather hard to read, the scale range is stated below each vegetation type].

In the period from which the peat under one stone of the row has been

dated, the results have been fine-tuned. The estimated date of peat under the

sampled stone of the row is between 3700 and 3540 cal BC, represented by

the heavy horizontal line.

 

Did society shape the environment?

A range of sites and studies have demonstrated the ability of people to

modify their environment. There is clear evidence from the later Mesolithic

period of the use of fire on the high uplands (around Black Ridge, northern

Dartmoor! between 5700 and 4300 cal BC. Other uplands in the region also

demonstrate the use of fire in the later Mesolithic (Bodmin Moor] and the

early to middle Neolithic [Exmoor and Dartmoor around 3600 cal BCI.

Management of upland areas would have been carried out for specific

purposes and exemplifies the domestication of nature for gain.

 

Neolithic monuments demonstrate the ability and motivation of the

population to exploit all parts of their environment, and the range of these

monuments was not constrained by environmental conditions. The Neolithic

groups would also have ‘inherited’ landscapes which had already been

controlled and managed by Mesolithic populations. They were not moving

into ‘wildwood’ contexts, although woodland did of course persist in places.

It is not possible to differentiate seasonal from permanent occupation, but a

total lack of regeneration of higher vegetation or scrub indicated persistent

use of places and spaces through the period.

It is generally accepted that Bronze Age field systems were occupied in

periods of favourable climatic conditions and abandoned during poorer

conditions. However, we are increasingly realising that the climate during the

Bronze Age was complex, and not as simple as it has previously been

thought, with more than one ‘favourable’ climatic period, and more than one

‘decline’ in the climate. If we accept the limited chronology for the

archaeology, then the period of abandonment does coincide with a climatic

deterioration; however, why didn’t earlier periods of climatic downturn

similarly impact on society, and why didn’t other more favourable periods

result in recolonisation? Clearly blaming climate is too simple a model!

 

The balance of society/environment through prehistory

The relationship between society and environment is dynamic both in space

and time. In the Mesolithic and Neolithic land into the early Bronze Age]

communities were probably buffered from environmental changes through a

number of adaptive strategies. They could time their movements around the

landscape to the seasons…a shorter summer may not even have been

noticed by groups. These groups were more than capable of controlling and

manipulating their local environments, and exploited the full range of the

landscape. It is debatable whether they even recognised a difference between

uplands and lowlands.

 

More specialised economies in later prehistory, and the investment in sub-

division of the landscape may have made society more sensitive to

 

environmental changes, but wider social, political and economic events may

have been as important, or more important, than climatic changes in

exploitation and use of Dartmoor in prehistory. A key lesson to learn from

the past is that uplands [especially, but not uniquely, Dartmoor] played a key

role in society throughout prehistory. They continue to do so!

Acknowledgements and collaborators

Ralph would like to acknowledge a range of sponsors for his work, including

the British Academy, Dartmoor National Park Authority, English Heritage,

 

Exmoor National Park Authority and the Leverhulme Trust. A range of co-

workers and collaborators have contributed to the academic and practical

 

At the end of Ralph’s lecture he was warmly thanked by Dr Tom Greeves for a

fine presentation, and this was enthusiastically endorsed by the audience.

The Research Lecture raised £294.52 for the Society’s Research Fund.

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