Monday, July 18, 2011

Losing the Family Farm: A Case of Human Population Collapse in the Irish Neolithic

It is said that Ireland skipped the industrial revolution and instead, after its moment of prosperity in the 1990s, went directly to post-industrial decline.  Similarly, Ireland for the most part missed the Paleolithic, that stage in which humans settled down to the ecological business of living on this planet with their full suite of evolutionary gifts, and skipped straight to the Neolithic – the period associated with the origin of farming.  Indeed, most of the substantial early settlement action in Ireland was by farmers of the Neolithic. Since there is significant disdain in environmental literature for agriculture, privileging instead the salad days of Paleolithic hunter-gathering times (“the original affluent society”) it would seem that Ireland missed out on the all the glorious action. 

My posts in the coming weeks will primarily be concerned with interrogating this disdain of many environmental writers for agriculture.  I start, though, by reviewing a case study in early Irish agriculture archeology, the Céide Fields, an early Irish agricultural settlement.  The fields are now covered by mountain blanket bog which grew up over the fields around the time that farming was abandoned.  Since the extensive field system of the Céide Fields were forsaken after a few hundred years of apparently continuous activity the question of whether this was the result of climate change or as a result of environmental modification imposed by farming has been raised.  Did it simply get too dry for farming, or did productivity crash and the human population crash with it?  If one of the complaints against agriculture is that it results in disastrous environmental modifications to the point where feedbacks ultimately result in declines in the human population, it will be instructive to see if this Irish case study provides evidence for the unsustainablity of early farming.  Why, if this case is not completely atypical, did agriculture ultimately supplant hunter-gather ways?  That is, if the evidence is that agriculture does not pay out its dividends easily, why has it almost universally adopted?  This question is made all the more pointed when laid alongside the re-evaluation of the hunter-gather mode of existence that has been proposed over the last couple of generations.  Thus, since early agriculture was more tenuous, hunter-gatherer life less arduous, how come the farmers won out?

Modern Homo sapiens has been around for 200,000 years or so, and adopted agriculture starting about 10,000 years ago.  To tell the human story as we do by moving quickly along to the story of civilization, an epiphenomenon of the agricultural revolution, is like recounting the adventures of one’s day by meticulously describing how you brushed your teeth.  In Ireland however, it is agriculture pretty much all the way.  Although, there is evidence of Paleolithic flint tools at some sites in Ireland, it is generally agreed that Ireland was not settled until after the Ice Age, approximately 8000 BC, by Mesolithic hunter-gatherers (throughout this post I retain the dating used by the principle sources I use).  There is a substantial body of work on Mesolithic peoples in Ireland, but these populations were tiny and Mesolithic sites are limited in their geographical distribution.  For instance at Mount Sandel, an early Mesolithic settlement and the earliest archeological site of significance in Ireland, the settlement is not very extensive.  The site is on eastern side of the River Bann near Coleraine in Northern Ireland and consists of several circular huts, with evidence of a considerable amount of flint working.  Although this is the most treasured of the Irish Mesolithic sites, it may have supported fewer than 15 people. [1] Because Mesolithic technology and culture is not a big factor in Ireland most of the interactions between the environment and people of Ireland have been during the Neolithic – farmers from the beginning.  This makes Ireland a compelling place to examine the implications of early agriculture on the land, and in turn for studying the peoples who depended upon these early agricultural environments.

A substantial influx of people, their livestock and their crops arrived in Ireland in the early Neolithic starting approximately 4000 BC.  The animals they brought included cattle, sheep (or goats), and pigs (though these may have been wild ones).  Dogs and cats are also associated with the Irish Neolithic, though dogs are found at older pre-agricultural sites.  Laurence Flanagan reasons that the national herd was required to be of considerable size for it to remain genetically viable. [2]  This raises the question of transportation – that’s a lot of people and their livestock required for colonization in the early years of the Neolithic.  He envisions them coming over in umiak vessels (timber framed and skin covered boats), traveling from Britain rather than from continental Europe.  Varieties of wheat and barley are also found at several Neolithic sites.  Thus these farmers lived on crops as well as livestock.  Planting of these cereal crops and tending animals required the clearing of the primeval forest. In addition ploughs were used to prepare the soil.  The changes in life-style and ecology associated with the Neolithic required therefore a new set of technologies (better axes, ploughs initially with stone blades, pottery) and the landscapes of Ireland were modified where these new methods were employed.

Associated with several Neolithic sites in Ireland is evidence of substantial field systems including the very substantial ones found near Ballycastle in Co Mayo in the West of Ireland.  These are known as the Céide Fields and although relatively little of this system has been exposed they are known to extend over several square kilometers beneath the mountain blanket bog.  The story of the discovery of the Céide Fields is a charming one.  Piles of stones were noticed in the bog by a local schoolteacher Patrick Caulfield in the 1930 as he cut turf for his fire.  Noticing that they were at the base of the turf bank and appeared to be deliberate in design he assumed correctly that they were archeological finds. The fields were later excavated and studied in detail by his son Séamus who studied archeology in college many years later.

Since that time Séamus Caulfield and others have been involved in detailed studies of the site. The excavated portions of the field system have walls running parallel to the relief of the land.  These longer walls that run continuously for some distance are then subdivided into smaller fields.  Primarily their purpose was for managing and grazing livestock, although there is also evidence of wheat production.  The warmer climate that existed at that time would have ensured almost year-around cattle foraging. [3] At the site as well are enclosures and “megalithic” tombs. Though the dating of the site has apparently been difficult, farming is associated with the site from 3700 BC till 3200 BC.   Based upon the supposed extent of the system up to 250 families may have been supported at this site.  Gabriel Cooney in discussing the system in his wonderful Landscapes of Neolithic Ireland says that the Céide Fields embodies “a new landscape perspective”.  He is pointing out, one assumes, the novelty of the wall system and the manner in which these walls organized the mobility of people living the landscape.  

Why were these ingenious and novel field systems abandoned?  Was it a result of unintentional mismanagement, or a consequence of climate change?  A contributor on Wikipedia speculated “that the removal of the tree canopy helped cause this change”, and goes on to argue that the tree removal led to the creation of an iron pan, that resulted in the encroachment of blanket bog.  Quite correctly, another contributor calls for support for these speculations. 

Fortunately, Michael O’Connell and Karen Molloy from the Department of Botany at National University, Galway investigated the dynamics of woodland and farming during the Neolithic drawing upon the pollen diagrams constructed for the Céide Fields and other locations in mid-western parts of Ireland.[4]  Such diagrams are constructed from sample cores, usually taken from the bog, which allow the investigator to reconstruct the vegetation history of a region.  The period of intensive farming at the Céide Fields coincided, of course, with the deforestation of the region – tree pollen is reduced in the record. The period in which this farming occurred predated the somewhat synchronous Elm-decline occurring at other sites in Britain and Ireland, a tree die-back that seemed to have been the result of tree pathology rather than the axe.  O’Connell and Molloy agree that “the circumstance and factors that gave rise to the rather sudden cessation of farming and the elaborate field system are of particular interest.”  The evidence from the pollen record points to a “decrease in the precipitation/evapotranspiration rates” (to you and me this means it got drier).  However, they concluded that this alteration in the climate “need not be considered as a cause of the abandonment of the field system.”  So what did?  On this point these authors remain silent.

Lucy Verrill from Edinburgh University and her colleague Richard Tipping from University of Sterling have recently reconsidered the evidence of the impact of Neolithtic farming on the landscape and environment.[5]  The pollen deposits that they examined from Balderg Beg, Co Mayo (close to the Céide Fields) indicated that peat accumulated from 5590 to 5330 BP (approx 3580 - 3320 BC!) and was “probably triggered by farming activities”.  Their soil analyses showed significant soil erosion and they claim that this may have been “a causal factor in the local cessation of agriculture”.  Thus, although climatic factors clearly contributed, soil quality may have been the overriding proximate factor leading to the abandonment of the field system. 

Ultimately early farming in Ireland must be placed in its economic context.  Although in the analysis of Verrill and Tipping, farming in Ireland at that time showed a “maturity and confidence” missing elsewhere in the British Isles, nonetheless, early farming was sensitive both to the vagaries of the North Atlantic climate combined with the fragility of the environment in the face of agricultural disturbances.  Climate change and soil erosion together resulted in a several hundred year decline of farming in the region.  We do not, of course, know the fate of the farmers and their families but it is quite clear that as the landscape changed to bog, a significant population could no longer be sustained in that region.

The Céide Field provides an example of the marginal nature of farming in northwest Europe in the Neolithic.  The case study, though not quite as dramatic as some other reversals that Jared Diamond presents in his volume Collapse, still serves to underscore the notion that agriculture which can, temporarily at least, support or indeed contribute to the swelling of the human population can also make life very precarious for that population.  Observations such as these contribute to questions about why agriculture was adopted in the Neolithic.  It cannot clearly be because farming was an unambiguous success.  The situation, as we shall review, was more complicated than this. 

[1] Laurence Flanagan (1998). Ancient Ireland: Life before the Celts. Palgrave-MacMillan, London. 233 pages
[2] Flanagan, 32
[3] Gabriel Cooney (2000). Landscapes of Neolithic Ireland, Routledge
[4] O’Connell, M. and Molloy, K. (2001). Farming and woodland dynamics in Ireland during the Neolithic. Biology and Environment (Proc R Ir Acad , Ser B), 101, 99-128.
[5] Verrill, L and Tipping R (2010) Use and abandonment of a Neolithic field system at Belderrig, Co. Mayo, Ireland: Evidence for economic marginality.  The Holocene 20(7) 1011-1021.

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