A Research Framework for the Archaeology of Wales
All Wales – Environmental
22/12/2003
For the purposes of this paper environmental
archaeology will be considered in its broadest sense, encompassing both those
areas of research that are focused explicitly on archaeological issues, and in
which a human dimension is central, and those that are essentially
palaeoenvironmental but have implications for archaeology. An understanding of
past environments is important in order to assess the extent to which human
communities may have been constrained or have adapted to changing conditions
and the extent to which environmental conditions may be a result, directly or
indirectly, of human activity. Apart from providing the environmental context,
both on a regional and local scale, and indicating the interrelationship
between people and the environment, other information that can be obtained from
environmental studies includes evidence about palaeoeconomies and diet,
funerary and ritual practices, social organisation and
trade.
As in other areas of archaeology in recent
years there have been various publications, either arising from conferences or
by individual researchers, suggesting directions for future investigations in
environmental archaeology (e.g. Bayley 1998, Edwards and Sadler 1999, Howard
and Macklin 1999, Brown 1997, Bell 2001). This paper takes account of this work
and has been prepared by Astrid Caseldine in collaboration with Professor Mike
Walker, Professor Martin Bell, Dr John Crowther, Professor Frank Chambers,
Professor Mark Macklin, Professor John Allen and Dr Paul Hughes. The paper is
confined largely to environmental aspects of archaeological science, although
dating techniques are briefly considered because a good chronological framework
is as essential for palaeoenvironmental studies as it is for other areas of
archaeology, and lipid analysis is referred to as it clearly overlaps with
other aspects of palaeoeconomic research and diet. Human bone evidence is not
included apart from recent studies using stable isotope analysis, which are of
wider dietary, economic and environmental significance.
This paper follows the original remit that the
environmental evidence should be reviewed on a pan-Wales basis, but takes into
account the four regions, i.e. the northwest, the northeast, the southwest and
the southeast. Of necessity, given that all time periods are considered, only a
brief evaluation of the strengths and weaknesses of the existing data will be
presented here, but a full review of the environmental evidence will be given
in Environmental Archaeology in Wales 2nd edition (Caseldine in prep.).
Opportunities for future research opportunities are suggested, including
possible approaches. Threats are considered briefly and finally recommendations
and key priorities are outlined.
Environmental Data
This is very much dependent on there being the
necessary conditions for survival.
Pollen: Strengths and weaknesses
One of the strengths of palaeoenvironmental
studies, particularly pollen, is the ability to provide a record of continuity
and change in the landscape. In Wales the peaty acid soil conditions favour the
preservation of pollen and over 400 pollen sites have been
examined. A wealth of environmental evidence is available to the archaeologist,
at least in broad landscape terms, but a more detailed examination of the
evidence reveals that there are significant gaps in the distribution of the
sites and that the quality of the data is variable. The former reflects
not only the availability of suitable deposits but concentrations of sites
frequently reflect specific research projects and the work of individual
research students. Hence in north Wales there are clusters of sites in Snowdonia, Ardudwy
and western Rhinogau, Mynydd Hiraethog and the Berwyns, whilst further south
there are concentrations in the Cambrian Mountains and the lowlands to the
west. In south Wales concentrations of sites lie in the
Preseli area and the Black Mountain, Brecon Beacons and Abergavenny Black
Mountains. Certain individual site areas have, because of their high scientific
value, been the focus of repeated investigation, notably Tregaron Bog (Cors Caron) and Borth Bog (Cors Fochno). Along the coast, again there are
'hot spots' of research activity, most noticeably in the area of the Gwent
Levels of the Severn Estuary (Walker et al 1998; Bell et al
2000), but other areas where there has been some research, although of a less
intensive nature, include the coast of Pembrokeshire (Lewis 1992) and
north-west Wales (Bedlington 1994). Investigation of peat deposits associated
with riverine alluvial sediments has been very limited, but examples include
the Ilston valley (Saunders et al 1989) and Caldicot (Nayling and
Caseldine 1997).
The usefulness of a particular pollen diagram
to the archaeologist also depends on the length of time represented and the
number of levels counted which also vary considerably, again partly dependent
on the nature of the deposit and the research emphasis. Hence at Llanllwch Bog,
near Carmarthen, Thomas (1965) produced a diagram covering the Holocene, whilst
Donald (1987) concentrated on the Late-glacial Loch Lomond Stadial and
early Holocene and, more recently, Rosen (1998) has undertaken a detailed
investigation of the upper deposits concentrating on the last 500 years only.
Related to this is the question of an independent chronological control, with
around 25% of all pollen records in Wales having 3 or more radiocarbon dates
and the remainder having either none or only one or two dates; the result is
that landscape changes can be more accurately related to the archaeological
record in some areas than others. Hence in southeast Wales a well-dated
Late-glacial diagram is that from Llanilid (Walker and Harkness 1990; Walker et
al 2003), whilst the Holocene pollen sequence Site 1 at Goldcliff (Smith
and Morgan 1989) is particularly well-dated and at other sites in the
inter-tidal area and Gwent Levels there are a number of dated diagrams,
building up a good chronology for the area as a whole. Another area for which
there is excellent dating evidence is Waun-Fignen-Felen (Cloutman 1983) in the
Black Mountain Range. In mid-Wales Tregaron is also well dated with dates from
several sites within the bog. The earlier deposits at Nant Ffrancon (Hibbert and
Switsur 1976) in Snowdonia are well dated but the latest date is 4255±50 BP
(Q-907), limiting interpretation of the later changes in the record. At Llyn
Cororion (Watkins 1990), by contrast, in lowland Gwynedd dates range from c
9700 BP to 800 BP, providing a better chronological control in relation to
archaeological and historical events. Radiocarbon dating is unsuitable for
dating landscape changes within the last 300-400 years and the use of other
dating techniques, such as 210Pb and carbonaceous
particles, has only been applied in a few instances (Jones et al 1985,
Rosen 1998, Chambers et al 1999). Similarly, although tephra has been
identified at sites in the Cambrian Mountains, the use of tephrochronology as a
means of dating and correlating peat sequences in Wales has yet to be fully
developed (Buckley and Walker 2002).
Much of the pollen work has been undertaken
independently of any archaeological work and, in a number of cases,
consideration of the role of anthropogenic activity, if considered at all, is
secondary to the main aim of the research, although the results may have
significant value for archaeology, for example in sea-level studies. In recent
years there have been an increasing number of integrated pollen and
archaeological studies, frequently involving other lines of environmental
evidence as well, particularly from wetland sites such as Caldicot (Nayling and
Caseldine 1997) and Goldcliff (Bell et al 2000) in the Severn Estuary,
Abercynafon (Earwood and Caseldine forthcoming) in upland south Wales and
Prestatyn (Bell et al in prep.) in north Wales. Other examples of
integrated studies include the work of Barton et al (1995) at Waun-Fignen-Felen building on the
earlier work of Smith and Cloutman (1988), Nant Helen (Chambers et al
1990), Ardudwy (Chambers et al 1988) and Cefn Graeanog (Mason 1998),
Brenig (Lynch 1993), the Breiddin (Musson 1991), Carneddau (Walker 1993), and
Corn Du and Pen-y-fan (Chambersand Lageard 1998), but the number of
investigations involving archaeological excavation, on-site and off-site
palaeoenvironmental analyses are still comparatively few. Other weaknesses of
the data include a lack of high-resolution analyses, although there are
exceptions as in recent work at Tregaron (Hughes et al 2001). Much
palynological research is not readily accessible as it is in unpublished PhDs
or is in the 'grey literature' of unpublished reports prepared for developers as part of
the planning process.
In relation to the main archaeological periods
there are very few pre Late Devensian pollen sites. Studies of Late-glacial
sites number fewer than 30 with the greatest concentration in Snowdonia. In general they have provided evidence on climate and associated
vegetation changes, but indicators of climatic oscillations recorded in some
diagrams are not recorded in others, which suggests that either these events
were of such short duration that they did not affect the local plant
communities or insufficient resolution in pollen sampling. In addition not all
of the sites have produced a full Late-glacial record, e.g. Hendre-fach and
Dolau-duon (Donald 1987) in southwest Wales. Although dating control is poor
for many of the sites several of the pollen profiles have been closely dated, eg
Llanilid (Walker and Harkness 1990, Walker et al 2003, Nant Ffrancon
(Hibbert and Switsur 1976) and Llyn Gwernan (Lowe 1981, Lowe and Lowe 1989).
Possible evidence for human activity, notably fires, has received little
attention, although the anthropogenic significance of charcoal, particularly at
this time, is debatable.
A number of pollen records cover the early-mid
Holocene and much of the focus of investigations has been on the arrival and
expansion of vegetation species reflecting an ameliorating climate, which has
implications as far as the resources available for exploitation are concerned.
Sites where it is suggested Mesolithic environmental impact can be identified
are still relatively few and are mainly from upland areas, for example
Waun-Fignen-Felen (Smith and Cloutman
1988, Barton et al 1995) and Pen Rhiw-wen (Cloutman 1983). Before the
work by Lewis (1992) in west Wales and Bell and colleagues at Goldcliff (Bell et
al 2000) in the Severn Estuary investigation of coastal sequences was
largely focused on sea-level change rather than exploitation by Mesolithic
communities. Further work is currently in progress at Goldcliff East and
Redwick in the Severn Estuary and at Prestatyn (Bell et al in prep.) in
north Wales. Evidence of Mesolithic activity from inland lowland sites is
generally lacking with, for example, only tentative evidence from Llyn Mire
(Moore 1978).
A number of studies have been concerned with
blanket peat formation and the impact of human activity and have demonstrated
the variable date for peat initiation in Wales (Caseldine 1990, Chambers 1996).
Evidence from sites such as Waun-Fignen -Felen (Smith and Cloutman 1988)
demonstrates that
ombrogenous peats began to form as early as the Mesolithic, but
at other sites peat development began during the Neolithic and Bronze Age and
even later (Chambers 1981) The variation in dates for peat initiation suggests
that it cannot be accounted for by a purely climatic hypothesis and it is
considered that anthropogenic activity, as well as local site factors, is
likely to have been important.
Evidence for pre-elm decline cultivation is
scarce and there is the added problem of the uncertain identification of cereal
pollen. The evidence for small-scale Neolithic clearance is widespread but much
of the evidence is from the uplands rather than the lowlands and there is a
lack of evidence from the river valleys and from sites close to the main
concentrations of Neolithic tombs and other sites (e.g. Pembrokeshire, Gower,
Anglesey, etc.). Evidence for cereal cultivation is limited as is evidence from
archaeological sites. One problem is the probable under-representation of
cereal pollen in sites some distance from the activity, especially if it is
small-scale in a largely wooded landscape.
Pollen sequences from the Bronze Age suggest
increasing clearance activity but there appears to be some variation in the
extent and timing of the activity (Mighall and Chambers 1995, Caseldine et
al 2001). A predominantly pastoral economy is indicated but there is some
evidence for cereal cultivation, including the uplands, for example at Bryn y
Castell (Mighall and Chambers 1995) and the Berwyns (Bostock 1980) in north
Wales and the Brecon Beacons (Chambers 1982) and Nant Helen, Mynydd y Drum
(Chambers et al 2000) in south Wales. Although there have been studies
involving investigation of Bronze Age monuments and nearby peat deposits these
have been relatively few. Further palaeoenvironmental work is currently in
progress as part of the Cadw Funerary and Ritual Sites project to enhance our
understanding of the landscape context of these monuments. Apart from the
recent work at Cwmystwyth (Mighall and Chambers 1993, Mighall et al
2002), little is known about the impact of Bronze Age mining activity on the
surrounding landscape. Equally, until recently, pollen work in coastal areas
has concentrated on sea-level change rather than the environments available for
exploitation and their use.
Pollen records again suggest variation in
clearance activity during the later Bronze Age and Iron Age. Evidence from some
areas suggests substantial clearance occurred in the late Bronze Age and that
they remained largely open into the Iron Age, for example at Bryn y Castell
(Mighall and Chambers 1995) and Llyn Morwynion (Caseldine et al 2001),
whilst in other areas there is evidence for some woodland regeneration followed
by further clearance during the Iron Age or Romano-British period such as at
Cefn Gwernffrwd in mid-Wales (Chambers 1982) and in Ardudwy (Chambers et al
1988). Indeed one of the problems is that frequently radiocarbon dates are
fewer for later prehistory and, more particularly, historic periods with the
result that it is sometimes unclear whether, for example, changes should be
attributed to Roman influence or the changes had already occurred before that
period or in the post-Roman period. A predominantly pastoral environment is
suggested although there is also evidence of arable activity, for example at
Bryn y Castell (Mighall and Chambers 1995). Pollen evidence from archaeological
sites is largely from northwest and southwest Wales, apart from the Breiddin
hill fort in northeast Wales and the recent work at Goldcliff in southeast
Wales. Of the former two areas it is mainly sites in northwest Wales where
off-site as well as on-site analyses have been undertaken. Again it is only
recently that the exploitation of coastal wetlands has been investigated and
this has largely been confined to work in the Severn Estuary. The impact of iron working
has only specifically been investigated at a few sites, notably Bryn y Castell
(Mighall and Chambers 1997) and Crawcwellt (Chambers and Lageard 1993). The environmental context of Late Bronze Age/early Iron Age hoards has
received little attention apart from at Llyn Fawr and most recently at
Princetown (Jones et al 2003).
Apart from investigations in northwest Wales
and on the Gwent Levels in southeast Wales, pollen evidence from sites of
Romano-British date is relatively scarce and, as already mentioned, dating of
longer sequences is often poorer for this and for later periods so that inferences
about continuity and change and regional variations are restricted. The same
applies to early medieval and later sequences, although a post-Roman woodland
regeneration can be identified in a number of areas (Caseldine forthcoming).
Proxy climatic data are limited but there is some evidence for climatic
deterioration c 1400 BP, for example from the Migneint (Blackford and Chambers
1991). Although many diagrams cover the medieval period, comparatively little
pollen work has been undertaken on medieval archaeological sites with few
attempts to put either castles, rural, urban or ecclesiastical sites into a
broader landscape context. The usefulness of pollen and other studies in
interpreting medieval rural sites is demonstrated by the results from Cefn Graeanog
(Chambers 1982) and more recently from Ynys Ettws (Caseldine forthcoming) as
part of the Cadw Deserted Rural Settlement Project. In general the opportunity
has not been taken to test historically derived ideas against the
palaeoenvironmental record. A few palaeoenvironmental investigations have been
concerned with the impact of industrial activity (e.g. Rosen 1998, Rosen and
Dumayne-Peaty 2001), although such multi-proxy approaches are not without
problems.
Plant macrofossils: strengths and weaknesses
Because of the survival of charred material on
dry land sites a relatively large number of sites have yielded charred plant
remains but the quality of the evidence varies both from period to period and
spatially within Wales. The main contribution has been in providing
palaeoeconomic information, particularly about crop husbandry practices. The
main weakness has been the lack of sieving/flotation programmes to recover evidence. Substantial sieving programmes
have been carried out at only a handful of sites, for example, Llawhaden
(Williams and Mytum 1998) and Cefn Graeanog (Fasham et al 1998).
Furthermore, the absence of detailed chronostratigraphic control on some sites
means that interpretation of changes in crop husbandry is sometimes limited. In
addition in some cases samples have been taken but alack of funding,
particularly applicable to developer sites, has resulted in samples remaining
unprocessed, whilst in other cases analyses remain unpublished
Apart from hazelnut shells from a few sites,
little is known about the exploitation of other plant resources during the
Mesolithic period. This is at least partially a result of there being few
attempts to recover material by sieving programmes, although exceptions are
Prestatyn (Bell et al in prep.) and Goldcliff (Bell et al 2000).
The number of Neolithic sites from which plant macrofossil evidence has been
recovered is few and the assemblages are generally poor. Exceptions are the
middle Neolithic site at Plas Gogerddan (Caseldine 1992) and the Late Neolithic
Capel Eithin (Williams 1999) while the assemblage from Gwernvale (Caseldine in
prep.) is of particular note because of the remains being associated with a
settlement of early Neolithic date below a chambered tomb. The evidence from
southeast Wales for cultivars during this period is especially limited being
confined to emmer wheat and Celtic bean impressions from Ogmore on Sea (Webley
1969) and Ogmore (Hillman 1981), respectively. By the Bronze Age there are more
sites but the assemblages are still generally small, although again there are
exceptions with, for example, a relatively rich assemblage from the middle
Bronze Age site of Glanfeinion (Britnell et al 1997). Evidence from
northwest Wales is scarce while, in contrast to the previous period, there is
more from southeast Wales, including data from wetland sites. Evidence from the
Iron Age is similarly scarce and in some cases even scarcer than in the Bronze
Age particularly, for example, in southeast Wales. Even in southwest Wales, at
the Llawhaden group of enclosures (Williams and Mytum 1998), although there is
more Iron Age evidence than at most sites, there is still more Romano-British
than Iron Age evidence from Dan-y-coed. Uncertainty
of the date of contexts from late prehistoric through to the Romano-British
period is an added problem. The possible impact of the Romans on agricultural
production is difficult to assess when there is alack of evidence for what went
before. This is particularly the case in southeast Wales. Certainly there is
more evidence available for the Romano-British period but the database is still
limited, restricting inter-site comparisons and the identification of the
adoption or rejection of agricultural strategies and regional diversity. Early
medieval evidence is scarce with, at most, only one or two sites per regional
area. Hence the possible effect on farming of the withdrawal of the Romans is
difficult to assess. Although more information is available from medieval sites
and a range of types of site have been examined, again the conclusions that can
be drawn are much more limited when the evidence is considered by regional
area, or the relationship between different types of site, for example
castles/towns and their regional hinterlands, is examined. Very little evidence
is available from urban sites compared with England.
Faunal remains: strengths and weaknesses
As with plant remains, animal bone assemblages,
with the exception of assemblages from Palaeolithic
cave sites in Gower, South Pembrokeshire, the Wye Valley and northeast Wales,
are generally poor until the Romano-British period. In most cases bone has been
recovered by hand rather than sieving so that small mammal, bird and fish bone
are under-represented in the faunal record. Assemblages cannot always be accurately
assigned to specific periods. Relatively few of the earlier faunal studies
involved the quantitative assessment of the species represented, age and sex
data, and metrical analyses. Interpretations were therefore limited, whereas
more recent reports are much more informative.
Faunal
studies have made a major contribution to environmental reconstruction during
the Palaeolithic; the majority of evidence being from cave sites such as
Pontnewydd (Green 1984), Coygan (Currant and Jacobi 1997) and Paviland (Aldhouse-Green
2000). The main weakness is the uncertain provenance of the
remains from many of the caves, and this applies to later periods as well. Bone
assemblages for the Mesolithic through to the Iron Age are generally poor
because of the acid nature of the soils over much of Wales. Apart from caves,
the main source of bone evidence for the Mesolithic is coastal deposits where
preservation is good although evidence is sparse. The importance of sieving programmes is demonstrated by the recovery of fishbone from Goldcliff (Ingrem
2000). The discovery of animal footprints in the Severn Estuary provides an
additional source of evidence (Allen 1997). Further examination of the use of
animal resources in coastal environments during the Mesolithic and later is
currently in progress by Bell and colleagues. Evidence from the Neolithic is
scarce, particularly from southeast Wales, with poor assemblages. The same
applies to the Bronze Age with again small assemblages and little evidence from
some regions. Next to no evidence is available from northeast Wales whereas
slightly more evidence is available from southeast Wales than in the previous
period and where at inertial sites such as Redwick both bone and footprints
have been found and work is currently in progress. Several late Bronze Age
assemblages from wetland sites in the southeast region, notably Caldicot
(McCormick 1997), have enhanced the state of knowledge significantly. In
general Late Bronze Age/ Iron Age assemblages are relatively poor although an
increased size of the later Iron Age assemblages is recorded at some sites with
a major increase occurring in Romano-British times, e.g. Coygan Camp (Westley
1967). At Collfryn the reverse applies where a large Iron Age and smaller
Romano-British assemblage was recovered (Jones 1987). A substantially greater
amount of bone has been identified from Roman sites but much of this evidence
comes from only a few locations, notably Caerleon, Caerwent, Segontium, and Loughor and there is little evidence for the relationship
of these sites to the surrounding rural area and to native sites. As with the
plant macrofossil evidence only limited conclusions can be reached as far as
changes in agricultural practice and regional differences are concerned. The
only early medieval site to have yielded a large assemblage is Dinas Powys
(Gilchrist 1987), which limits any understanding of wider agricultural
practices. Larger assemblages have been recovered from medieval sites with
relatively good information available from castles and towns. However,
assemblages from ecclesiastical and rural sites are much scarcer and the
relationship between, for example, towns/castles and rural sites has received
little attention. Although post medieval assemblages can provide valuable
information about the development of modern breeds of livestock, in general
little consideration has been given to them.
Mollusca: strengths and weaknesses
Mollusc evidence is relatively limited because of the comparatively restricted
distribution of the generally calcareous contexts suitable forth survival of
terrestrial
molluscs in Wales, but there are abundant areas of
coastal deposits in which marine molluscs can be found.
Significant studies of non-marine Mollusca of Mesolithic date
include Cwm Nash in south Wales (Evans at al 1978) and Prestatyn in north Wales
(Bell et al in prep), while at Stackpole Warren land Mollusca associated
with Iron Age field systems and overlying dunes (Evans and Hyde 1990) and land
and freshwater assemblages from the late Bronze age site at Caldicot (Bell and
Johnson 1997) have been investigated. An early-Holocene freshwater assemblage
was obtained from Llangorse (Walker et al 1993). Marine molluscs are important as indicators of diet and most of the evidence is from
Roman or later sites and generally has involved identification with little
further analysis. The only certain middens of Mesolithic date
are from Prestatyn (Bell et al in prep) with a possible Mesolithic
midden at Nanna's Cave on Caldey (Lacaille and Grimes 1955). Investigation of
the growth lines of cockles at Prestatyn has produced evidence of seasonality
(Fancourt 1999). At Stackpole Warren middens date from the later Bronze Age
through to the medieval period (Cole 1990) and at Ty Mawr there is a detailed
study of a midden considered to date from the end of the first millennium BC
(Evans and Evans 1986). Marine Mollusca have also been used in amino acid
dating of Pleistocene deposits, especially in Gower (Henry 1984, Bowen et al
1985, Bowen 1999).
Stable isotope analyses: strengths and
weaknesses
A recent important development has been the
application of stable isotope analyses to human skeletons in Wales, thereby
providing information on diet and, in turn, issues of seasonality and
subsistence which are of particular value in earlier prehistory. Results
suggest the importance of marine resources in the diet of later Mesolithic
individuals from caves in south and north Wales (Schulting and Richards 2000),
whilst the evidence from human remains from an earlier Neolithic chambered
cairn in south Wales suggests there was minimal use of marine resources and
terrestrial animals were most important in the diet (Richards 1998, Schulting
and Richards 2000). Neolithic and Bronze Age skulls from the Severn Estuary
also suggest minimal use of marine resources whereas an Iron Age/early Roman
skull shows slightly more and a medieval skull indicates that around 40-50% of
dietary protein was from marine resources (Richards and Schulting 2000). The
main weakness is the limited application of this technique so far and the need
for analyses from a wider range of locations and in tandem with faunal and
botanical analyses. AMS dating is important to support this work. Stable
isotope analysis has also recently been used to correlate Late-glacial climatic
events at Llanilid (Walker et al 2003).
Insects, mites etc: strengths and weaknesses
Comparatively few investigations of insects and
mites have been undertaken in Wales but they have provided valuable
information, not only about the environment and land use, but also about the
use of buildings/structures. The paucity of studies is at least partly
restricted by the availability of suitable waterlogged contexts but coastal
peat deposits, for example, are widespread and offer potential for further work.
Investigations of changes in Late-glacial
climate and environment include work at Glanllynnau (Coope and Brophy 1972) in
northwest Wales and Llanilid (Walker et al 2003) in southeast Wales.
Work directly associated with archaeological investigations in southeast Wales,
for example, includes that at inter-tidal sites in the Severn Estuary ranging
in date from the Mesolithic to the Iron Age (Smith et al 2000) and
palaeochannel deposits at the late Bronze Age Caldicot (Osborne 1997),
whilst studies in the northeast Wales archaeological region include those at
the Breiddin hill fort (Smith 1991) and, further south in the Brecon Beacons,
the upland Neolithic wetland site at Abercynafon (Panagiotakopulu forthcoming)
and Corn Du and Pen-y-fan Bronze age cairns,(Robinson 1998), in southwest Wales
the late Iron age site at Penycoed (Girling 1985) and Whitland Roman
road(Caseldine et al 1997) and in northwest Wales analysis of a peat
sample (Osborne 1987) from near the Neolithic site of Trefignath.
Charcoal and wood studies; strengths and
weaknesses
Charcoal has been identified from a large
number of sites, providing some information about the woodland resources
available, but there have been few detailed studies, except that from Cefn
Graeanog (Thompson 1998), of intra-site distributions. There has been a major
development of wood studies during the last decade but most of this has taken
place only around the Severn Estuary. Work has included analysis of the
submerged forest environments as well as analysis of wood from structures
ranging from Bronze Age trackways to medieval boats. Similarly, there has been a
significant increase in dendro-chronological dating in Wales in the last
decade. There are relatively few prehistoric archaeological sites in England
and Wales, which have produced dendrochronological dates, but dates have now
been obtained from the Neolithic upland site of Abercynafon (Nayling
forthcoming), the Bronze Age site at Caldicot (Hillam 1997) and from Bronze and
Iron Age sites at Goldcliff (Hillam 2000). Further work is in progress,
particularly in relation to Mesolithic submerged forests, in the Sever Estuary.
Dates from Roman sites include Caerleon (Hillam 1993) in southeast Wales and
Prestatyn (Morgan 1989) in northeast Wales. A number of medieval buildings have
now been dated by dendrochronology. However, the main weakness remains the
limited application of this technique on prehistoric sites and the need to
extend the dendrochronological record for Wales.
Soils: strengths and weaknesses
Apart from the investigation of buried
palaeosols at a number of sites, other soil studies have been more limited but
have included phosphate, magnetic susceptibility and soil micromorphological
analyses. Phosphate analysis has been undertaken on several sites of Neolithic
and Bronze Age date to confirm the presence of burials and cremations.
Phosphate analysis, either alone or with magnetic susceptibility measurements,
has also been used to identify activity areas such as at the lithic scatters
site at Boncyn Ddolin north Wales (Crowther 2001), or to determine the use of
buildings, phases of activity or land use at several sites ranging in date from
the later prehistoric through to medieval times, such as Moel y Gerddi and
Erw-wen (Conway 1988), Llawhaden (Crowther 1998) and Cefn Drum (Kissock 2000).
Redistribution of phosphorus has been examined in cave sediments from the lower Palaeolithic site of Pontnewydd (Jenkins 1997). Soil micromorphology has been
comparatively little used but has included work on soils from the Hiraethog
Moors (Lascelles 1995), the Mesolithic soil and organic layers from Iron Age
buildings and palaeochannel fills at Goldcliff (Macphail and Cruise 2000a,
2000b), and cave sediments from Pontnewydd (Jenkins 1997).
Geoarchaeological studies/geomorphology and
sediments; strengths and weaknesses
The most thorough investigation of sedimentary
sequences in relation to archaeological remains has taken place in the Severn
Estuary (Allen 1987,2000, Allen and Rae 1987), but the investigation of coastal
alluvial sequences elsewhere has largely focused on sea-level changes and
crustal movement. Recent studies in the Severn Estuary have included the
examination of the silts for the presence of tidal laminations and groupings of
laminations into bands in order to help identify horizons of unusually large
rates of annual accumulation (Allen and Haslett 2002). These rapidly
accumulated sediments are very favourable for the preservation of evidence such as
animal footprint-tracks. High-resolution grain-size analyses of tidal silts
complement for aminiferal analysis and provide good evidence on rates and
senses of sea-level change.
The alluvial archaeology of non-tidal rivers in
Wales has been considerably under-researched in comparison to other parts of
the UK. Only a handful of sites has been investigated in relation to
archaeology including the Ilston Valley (Saunders et al 1989), Rheidol
Valley (Macklin and Lewin 1986, Vyrnwy (Lewin 1992), Dyfi (Johnstone et al
2002), Welshpool (Taylor and Lewin 1996), Buttington (Macklin et al
2002) and Caldicot (Taylor 1997), but at the last-named there was also a tidal
influence. A number of other studies of river systems including the upper
Severn, Teifi, Dee, Dyfi, Twyi and Rheidol, independent of archaeological
investigation, are currently in progress by Macklin and colleagues and have
implications for archaeology but there needs to be closer co-operation between
archaeologists and geomorphologists and sedimentologists.
Diatoms, foraminifera, ostracod, testate
amoebae: strengths and weaknesses
These analyses have been less frequently used
in Wales and mostly in palaeoenvironmental reconstructions that have been
undertaken independently of archaeological studies, notably in investigations
of sea-level change. However, with the increase in archaeological work in and
around the Severn Estuary some of these fossils are now being routinely
examined from archaeological sites. Diatom analysis has been more widely
applied than either foraminifera or ostracod analyses, which generally have
been under used. Similarly, there have been few studies in Wales using testate amoebae either as sea-level indicators, for example in the Taf estuary (Roe et
al 2002), or as palaeohydrological and palaeoclimatic indicators, for
example at Figyn-blaen-brefi (Buckley 2000).
Lipid analysis: strengths and weaknesses
Complementing plant macrofossil and faunal
analyses from sites, organic residue analysis provides additional information
about dietary habits. This technique has so far been used on relatively few
sites, for example the Walton Basin (Dudd and Evershed 1999).
Dating: strengths and weaknesses
One of the strengths of radiocarbon dating is
its wide applicability and the possibility of dating both on-site and off-site
events to enable correlations to be made. The development of AMS dating, which
allows very small samples of material (including single entities) to be dated,
the refinement of calibration curves by which14C dates can be converted to calendar years, and the application of a
range of statistical methods (e.g. Bayesian analysis) have significantly
strengthened its use. However, as has already been mentioned a large number of
pollen diagrams in Wales are either undated or are poorly dated. There are also
relatively few instances where off-site peat cores and nearby archaeological
sites have been independently dated to enable correlation. Chronological
control on sites is also often poor which results in limited interpretation of
crop husbandry and other agricultural/economic changes. Single entity dating of
charred plant remains from archaeological sites should improve this and help to
provide a better chronological framework for sites.
The main strength of dendrochronology is the
provision of ages in calendar years and, as has been discussed above, the main
weaknesses are that mastercurves for the prehistoric period are still being
developed and that in Wales very few prehistoric sites have been dated using
this technique.
Other techniques which have been used to
varying degrees in Wales include 210Pb
which is used to date very recent sediments, thermoluminescene used to date
mineral grains and burnt flint, optically stimulated luminescence used to date
sands, e.g. Aeolian sediments, Uranium-series used to date cave sediments, and
cosmogenic nuclides (based on isotopes as a result of cosmic radiation) used to
date deglaciation. Relative ages have been obtained from amino-acid
racemisation on marinemolluscs, while tephra analysis may eventually provide a
basis for correlation of peat deposits. This technique has recently transformed
palaeoecological research in the north of Ireland.
Research Opportunities
The strengths and weaknesses of the individual
data sets have been briefly summarised and opportunities for research will now be
considered on athematic basis. Some of the research opportunities identified
here are specifically archaeological issues whilst others are, in essence,
palaeoenvironmental but are of relevance to archaeological issues. Suggestions
as to how these research questions maybe approached are also included.
Environmental resource exploitation and
agricultural change: the development of agriculture and changing agricultural
practices
1. Any Palaeolithic site with environmental evidence requires exhaustive investigation,
even when there is no direct evidence of human presence. Such work needs to be
closely linked with Quaternary research on non-archaeological sites. The
relative paucity of interglacial deposits means that they should receive a high
priority.
An interdisciplinary approach is required,
including detailed work on geomorphology, sedimentary sequences and all
associated biota to provide a basis for environmental reconstruction and to
enable landscape and predictive modelling.
2. Although
there have been a few studies concerned with the possible influence of
Mesolithic communities on the environment the evidence is scarce. These have
largely been in the uplands with only recently work on coastal landscapes. The
way in which Mesolithic communities may have been using different landscapes is
imperfectly understood and both the question of seasonality and the nature of
the Mesolithic economy require further exploration.
There is a need for the investigation of sites
in a range of landscapes. Studies should focus on sites where the lithic and palaeoenvironmental evidence can be closely correlated. Buried land
surfaces beneath reservoir edges, former shorelines of natural lakes,
inter-tidal submerged surfaces and riverside sites, especially ecotonal sites,
offer opportunities for investigation. High resolution pollen analyses, plant
macrofossil analyses, charcoal and wood studies, faunal and insect analyses,
supported by an adequate dating programme, including dendrochronology if possible,
should be undertaken. Stable isotope analyses of human skeletons should also be
undertaken whenever suitable material is found.
3. The
evidence covering the Mesolithic-Neolithic transition is scarce. A few pollen
records exhibit pre-elm decline ‘cereal-type’ pollen. When did cereal cultivation
begin in Wales during the Mesolithic-Neolithic transition? Early Neolithic
‘clearance' episodes generally appear to be small scale. To what extent do they
represent opportunistic exploitation of naturally occurring clearings, ie to
what extent are early Neolithic economic strategies a development of late
Mesolithic intensification of wild plant food husbandry (cf Brown 1997)? At
what point did purposive clearance occur? When did animal husbandry begin in
Wales?
Pollen records with pre-elm decline 'cereal-type'
pollen need to be dated but, because of the uncertainty of 'cereal-type’
pollen, recovery and dating of charred plant remains from securely stratified
contexts is vital. Pollen analysis from small sites, for example the edge of
palaeochannels in river valleys, is required. Coastal wetland sites of
Mesolithic-Neolithic date may provide the evidence for the beginnings of animal
husbandry. Excavation of Mesolithic-Neolithic sites with sampling, sieving and
analysis of environmental evidence is needed. Stable isotope analyses of human
skeletons indicate changes in the use of resources and further studies should
be undertaken.
4. Occasional
'cereal-type' pollen grains and charred grain, generally in low amounts,
indicate some cereal cultivation during the Neolithic and earlier Bronze Age,
but what was the extent and spatial location of crop growing during this
period? What was the relative importance of arable/pastoralism?
Pollen studies in different landscape zones,
including small sites, river-edge and wetland/dryland edge sites in the
lowlands are required. Pollen sites with different pollen source catchments
within an area need to be investigated. Sampling and sieving programmes to recover charred grain need to be carried out during excavations.
5. The
development of field systems during the 2nd and 1st millennia BC and the
associated palaeoenvironmental evidence has received comparatively little
attention and requires further investigation.
Archaeological investigations should be
accompanied by palaeoenvironmental analyses, including pollen/ mollusc studies, soil micromorphology, phosphate analysis and radiocarbon
dates.
6. Changes
in clearance activity are recorded during the Bronze Age. A number of pollen
records show extensive clearance during the later Bronze Age and Iron Age and
charred cereals suggest a change from emmer to spelt but when did the latter
change occur and are there regional differences? What was the relative
importance of arable farming compared to pastoralism?
Are there regional and subregional differences in farming regimes during this
period?
On-site and off-site analyses (pollen, plant
macrofossils, animal bone), sieving and dating programmes are
needed to allow inter-site comparisons and to determine the date of changes in agricultural activity.
7. A greater amount of
plant macrofossil and animal bone evidence has been recovered from sites dating
from the Romano-British period in Wales but insufficient to say clearly what
impact the Romans had on agricultural production, the extent to which new
agricultural strategies were adopted and whether regional differences are
discernible. Pollen diagrams are frequently inadequately dated as are the
archaeological contexts of the macrofossil evidence from Iron
Age/Romano-British sites.
As for the previous period, on-site and
off-site analyses (pollen, plant macrofossils, animal bone), sieving and dating
programmes, are needed to allow inter-site comparisons and to determine the
date of changes in agricultural activity.
8. In contrast to the
preceding and the following periods, evidence is scarce for the early medieval
period. Continuity and change and the nature of the early medieval economy have
hardly begun to be explored.
Integrated archaeological/ palaeoenvironmental
studies (on-site and off-site) supported by adequate radiocarbon dating
programmes are required.
9. Plant macrofossil
and faunal evidence is more plentiful for the medieval period but further
investigations are required to determine regional differences in animal and
crop husbandry and to allow inter-site comparisons, for example the
relationship between castles and towns and their rural hinterland. Relatively
little information has been recovered from ecclesiastical sites, e.g. granges,
or rural sites. What was the effect of markets elsewhere in Britain?
Combined archaeological, documentary,
palaeoenvironmental, archaeobotanical and archaeozoological studies are
required.
10. The examination of
environmental evidence from deserted medieval rural settlements has been very
limited, but such evidence can help to determine whether they were permanently
or seasonally occupied farms. Similarly, upland cultivation during medieval
times and later has not been fully investigated.
Archaeological survey and excavation combined
with palaeoenvironmental and documentary studies, including place-name
evidence, and supported by radiocarbon and/or other dating techniques is
needed.
11. Relatively
limited work has been undertaken on urban sites. Work on urban sites needs to
be targeted at certain areas. One area that would deserve attention is urban
waterfronts, which offer considerable environmental potential.
Environmental analyses supported by sieving
programmes, as appropriate, are required.
12. Although
recent work at sites in the Sever Estuary has increased our knowledge of
woodland management, the importance of woodland management in prehistory has
yet to be fully explored.
Investigations should include on-site and
off-site pollen, plant macrofossil and insect analyses, wood studies and
dendrochronology.
13. One
of the most significant developments in Wales during the last decade has been
the development of wetland archaeology. Wetland sites offer a much greater
potential for the investigation of resource exploitation and agricultural
activity either in the surrounding wetland or on the adjacent dryland.
Wetland sites should be thoroughly investigated
and a full range of palaeoenvironmental techniques should be
employed. Investigations should include radiometric dating and, if possible,
dendrochronology.
14. Further work is
required on the involvement of human agency in upland peat formation and needs
to be related to archaeological evidence in the area.
Pollen and soil studies, including soil
micromorphology, supported by radiocarbon dates are required.
Funerary and Ritual
1. There
have been relatively few investigations specifically concerned with the
environmental conditions at and surrounding funerary and ritual monuments. The
visibility of prehistoric burial and ritual monuments in the Welsh landscape
requires further investigation and this is currently in progress as part of the
Funerary and Ritual Sites project.
On-site and off-site palaeoenvironmental
investigations are required, supported by radiocarbon dates combined with
archaeological survey and excavation.
2. The
role that plant and animal remains may have played in burial and ritual
practices both in prehistory and later periods in Wales has received
comparatively little attention and requires further investigation.
Animal bone, plant macrofossil and pollen
studies need to be undertaken along with archaeological excavation.
3. The deposition of
Late Bronze Age/Iron Age metalwork hoards in wetland contexts is well
established. However, the investigation of the environmental context of such
hoards in Wales has been limited.
The excavation of such sites should include
palaeoenvironmental studies (pollen, insect, plant macrofossil and animal)
supported by an adequate radiocarbon dating programme.
Mining activity and industrialization
1. There
have been very few integrated archaeological/ palaeoenvironmental studies
concerned with the impact of Bronze Age copper mining in Wales and further
investigations are required.
On-site and off-site studies should include
pollen, wood/charcoal, plant macrofossils, insect, sedimentalogical, and
geochemical analyses.
2. Recent studies have
given some indication of the impact of iron working on the landscape but this
could be explored further.
Pollen, wood/charcoal, plant macrofossil,
insect, sedimentological, and geochemical analyses should be included.
3. There have been
very few studies concerned with identifying the impact of industrialisation on
the surrounding environment. Although there has been some investigation of the
impact of
industrialisation in the Lower Swansea Valley (Rosen and
Dumayne-Peaty 2001), there is scope for further work on the impact of
processing sulphide ores as part of the copper-smelting industry. The possible
impact of coal mining in South Wales on valley alluviation remains largely
unexplored. Similarly, only some exploratory work has been done on the loss of
coal dust into the tidal environment at the exporting ports and there is much
more to be learned.
Pollen, soil, sedimentological and geochemical
analyses supported by appropriate dating techniques should be undertaken.
Climate Change: The influence of climate on
human communities
Most palaeoenvironmental studies of climate
change in Wales have been carried out independently of any archaeological
investigation and the implications for archaeology in terms of settlement
patterns, exploitation and agricultural activity have generally been a
secondary consideration. The main exception is the Palaeolithic period where the reconstruction of past climatic conditions,
particularly through faunal analyses, has been central to the investigations.
1. Further
investigations are required to determine the complexity of climate change
during the Late
glacial in Wales.
Investigation of sites with a full Late glacial
sequence using a multi-proxy approach including good dating control is
required.
2. There
have been relatively few studies in Wales, compared with some other parts of
Britain, that have used peat deposits, specifically the plant macrofossil and
testate amoebae records, as proxy climatic indicators. Specific areas for
future research include investigation of the palaeoenvironmental evidence for a
general worsening of climate in the later Bronze Age, a 'deterioration' in
climate c400-600 AD and the implications for human communities at these
times. Is there any evidence for a 'Little Ice Age' in the palaeoenvironmental
record?
Proxy climatic studies using bog surface
wetness combined with good chronostratigraphic dating control are required.
Alluviation in non-tidal river valleys
Until recently there has been very limited work
on the history of alluviation in river valleys in Wales compared with other
parts of Britain and the alluvial archaeology of non-tidal river valleys in
Wales has been considerably under-researched. There are two main aspects to
this work, i.e. locational and palaeoenvironmental, both of which have
implications for archaeology.
1. How has river
development in Wales been influenced by late Pleistocene and earlier glaciations
and what are the implications for the archaeological record (Macklin 1999)?
2. What have been the
effects of channel and floodplain development during the Holocene on the
archaeological record (Macklin 1999)? How have they affected settlement and
land use as well as the preservation and visibility of the alluvial
archaeological record?
3. What
is the relationship between river alluviation and erosion episodes and climate
and land-use change (Macklin 1999)? To what extent can phases of intensified
river activity in Wales be linked to wetter and/or cooler periods of climate?
When did valley floor deforestation occur?
4. What impact did
extreme flood events during the Holocene have on settlement and ritual
practices/ landscapes in river valleys?
5. What are the
taphonomic factors that influence artefact movement and preservation in river
systems?
A multidisciplinary approach should be adopted
to elucidate the history and dynamics of human settlement in river valleys.
Geomorphological survey should normally precede archaeological survey of river
valleys. Data collected need to be compatible and of the appropriate
spatio-temporal scale for evaluating cause-and-effect relationships, and
representative reaches over an entire basin need to be examined (cf. Macklin
and Lewin 2003).
Coastal alluviation and sea-level change
Most studies have been concerned with sea-level
rise per se and have been undertaken independently of any archaeological
investigations. There are a number of research questions that are essentially
palaeoenvironmental but are of relevance to archaeology
1. To what extent are
the transgressive and regressive episodes of sea-level tendency in Wales coeval
from site to site, and region to region (Bell 2001) and how has this affected
exploitation of coastal areas in different parts of Wales at different times?
2. What are the factors
driving transgressive and regressive episodes locally as well as regionally and
to what extent have long-term processes and catastrophic events determined the
pattern of coastal environmental change (Bell 2001)?
3. What was the
character of the pre-inundation Mesolithic environment and the role of human
agency (Bell 2001)?
4 The besanding of
settlements is well known but more precise chronologies need to be established
for dunes in Wales.
5. The investigation of
boats and waterfronts would provide information about the transport of goods.
Multidisciplinary studies are required. A full
range of palaeoenvironmental analyses including sediment, diatoms,
foraminifera, rhizopods, pollen, plant macrofossils, beetles and animal bones
need to be applied to study changing environmental conditions. These
investigations need to be underpinned by high-precision radiocarbon dating and
dendrochronological dating. Investigation of well-stratified Mesolithic sites,
especially midden sites, is of high priority.
Threats
The range of threats is similar to that for
other aspects of archaeology and includes drainage of wetland sites, sand and
gravel extraction, liming of sites, afforestation of uplands, road and
industrial developments, natural coastal erosion, and erosion caused by leisure
and recreational pressures.
Another problem, if not a threat, is the often
limited resources available on developer funded sites which result in under-funding,
if indeed any funding, of environmental work. This is perhaps most apparent in
urban areas where sampling is either not undertaken or, if samples are
recovered, they are not analysed resulting in a loss of evidence.
Recommendations for the future and key general
priorities
A Welsh environmental archaeology database
already exists but this could be upgraded and extended to include human bone
data, radiocarbon lists and more detailed palaeoenvironmental data, for
example, additional pollen site data indicating the time period covered could
be included. This needs to be more closely integrated with other databases such
as the NMR and SMRs and the recently produced Holocene alluvial database
produced by Macklin and Lewin for Wales, Scotland and England.
The recording of the environmental potential of
sites should be standard practice during archaeological survey work, as it is
now on Cadw projects, for example the Funerary and Rituals Sites project.
There should be closer interdisciplinary collaboration,
particularly between archaeologists and earth scientists.
Environmental archaeologists/earth scientists
should be involved in the planning and field stages of projects, especially
where fellow scientists can benefit from the time-depth perspective provided by
archaeological sites (Bell 2001).
Of high priority is the need for more
integrated studies involving excavation and survey combined with on-site and
off-site analyses.
Similarly, multi-proxy approaches need to be
used to provide more comprehensive environmental reconstructions and, where the
sources of evidence are in agreement, to increase the level of confidence
regarding the interpretation.
Finally, it is essential that
palaeoenvironmental work, whether on-site or off-site, is supported by an
adequate radiometric dating programme. Sieving programmes of occupation horizons are
vital not only to recover palaeoeconomic evidence but also to recover material
for dating, especially 'single-entity' dating, i.e. AMS dates from single
pieces of wood, bone or seeds.
Paper prepared by A. Caseldine (University of Wales Lampeter)
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