Human impacts on vegetation in the Mesolithic and the value of slow science

Hunter gatherer fisher communities may have caused significant changes in vegetation composition in forests 8000 years ago, but we need to look at changing the structure of the academic jungle to encourage young researchers and facilitate efficient science.

After reading the title you must be asking yourself how this article could possibly go from pre-agricultural societies to critically evaluating contemporary academic culture, but bear with me.

Investigations led by researchers at the Graduate School for Human Development in Landscapes at the University of Kiel have revealed that environmental impacts on northern European forests by pre-agricultural societies are visible in the geological record.

Evidence from archaeological excavations and vegetation reconstruction in southern Norway indicate that the introduction of Nøstvet axes had a significant impact on forest composition.

The investigations were conducted as part of an archaeological survey prior to highway construction in the Bamble municipality south of Oslo. The region was under the Scandinavian Ice Sheet until about 12500 years ago (10500 BC), which compressed the land below what is now the North Sea. As the ice sheet retreated due to climatic warming signalling the end of the Last Glacial Maximum, the land gradually rebounded, emerging from the sea in a process known as isostatic uplift.

Archaeological evidence from Bamble indicates that humans migrated into the region as new land emerged, and predominantly inhabited the coastal zone. The survey excavated 30 Mesolithic sites in the area, dating between 8700-4000 BC.

Mesolithic sites in the region are often located on the shoreline to provide access to marine (fish, marine mammals, shellfish, seaweed), and terrestrial (freshwater, wood for fuel and construction etc.) resources.

No sites are recorded in the immediate vicinity of the lake as it was outside of the purview of the archaeological survey, and the researchers admit that this may introduce some bias into their results.

Poor preservation of organic remains on the archaeological sites increased the importance of environmental data reconstructed from sediments of Lake Skogstjern to provide indications of human-environmental interactions.

The section of the lake sediment sequence dating to the Mesolithic was sampled at 1-2cm intervals to produce a high resolution (temporal) of vegetation change. High resolution records are essential when attempting to decipher potentially subtle, short term, vegetation disturbance and change.

Often, achieving such high resolution is difficult due to issues with radiocarbon dating lake sediments and the the impact of bioturbation (mixing of sediment on the lake bottom due to faunal activity. In the case of Lake Skogstjern, fine laminations (layers) in the sediment suggested that bioturbation was minimal and allowed high resolution sampling.

Of course, time and cost also come into account when aiming to achieve high resolution. Palynology (pollen analysis) in particular can be extremely time consuming, with hours dedicated to preparation of samples in the lab, and identification and counting under the microscope.

Having previously worked on attempting to reconstruct human-environment interaction from lake sediments I could only have prayed for the opportunity to achieve such high resolution.

So now, on to those results.

The pollen evidence suggests that during the Mesolithic the region was dominated by dense, semi deciduous forest consisting initially of birch and hazel, with elements of oak, pine, elm, and lime. In the immediate vicinity of the lake alder grew in abundance.

The pollen record is also conspicuous for a multitude of short, sharp changes in the proportion of forest trees, as well as the near continuous presence of herbs and shrubs indicating forest clearances.

The researchers argue that while the presence of light demanding herbs and shrubs can be explained by the natural occurrences of forest openings, they can equally be explained by artificial, human induced forest opening.

Furthermore, the recurrent, short term, reductions in forest tree proportions in conjunction with concomitant increases in open canopy plants suggest an active human manipulation of the forest composition.

The active production of forest openings, by burning or tree cutdown, by Mesolithic communities have been suggested to assist hunting of large game, and to facilitate the growth of specific plants for use as building materials or tool production.

The presence of charcoal dust particles in the sediments suggest that fire was a fairly common occurrence in the area. While ascribing causality to these fires is not possible, the authors do note that fires are rare in hazel and birch dominated forest.

Maximum proportions of hazel pollen coincidental with high charcoal abundance is thus suggested to indicate burning to encourage hazel growth.

What is most interesting is the distinct shift in forest composition that sees distinct increases in oak, lime, and ash, coincides with evidence for the production of Nøstvet axes in the area in the late Mesolithic around 5600 BC.

These axes are commonly found in coastal areas, or in proximity of large water bodies, leading to the interpretation of these axes as a specialised woodworking tool for the production of dugout canoes.

Lime, a soft, light, easily workable wood, is particularly favoured for the production of dugout canoes and wooden tools.

The authors argue that the association between the emergence of Nøstvet axes and increased proportion of lime in the pollen record indicate a link between vegetation composition change and technological change in the local population.

As is usually the case in human-environmental interactions, ascribing causality in the relationship is difficult. Did increased proportions of lime in the landscape prompt the development of Nøstvet axes?, or did the development of new technologies, result in the increase in lime for human exploitation?

The Mesolithic in northern Europe sees significant changes in vegetation composition, with deciduous trees (oak, ash, lime, elm) replacing pine and birch dominated forest.

It is likely impossible to determine the exact human role in these changes. But the role of human activities in a feedback encompassing climatic warming and post glacial isostatic uplift, is likely.

One thing that leapt out at me while reading this paper is that research of this nature is becoming rarer and rarer.

It is careful and considered, avoids making sweeping conclusions, and rather suggests how the results can guide further research. But, what is most apparent in the sheer amount of time and effort invested in the project. A lot of research today tends to favour quick results, sweeping conclusions and a low effort:publication ratio.

I don’t really blame researchers for doing this, as it’s a game that needs to be played. Both funding organisations, and universities prefer extensively published researchers.

Now, this all goes towards a larger issue in all sciences, how is the quality of research, and researchers, measured?

Often, it seems that the quality of a researcher seems to be measured by how many publications she/he has produced and the prestige of the journals in which they are published.

To me, such generalistic indices are not only inadequate to measure the quality of research, but place certain fields, which often require long, extensive, and intensive periods of data gathering before publications are produced, at a distinct disadvantage.

Young and aspiring researchers are also becoming more and more disenfranchised with academia as they are forced to undertake high output research, rather than research they are actually passionate about, in order to gain future funding and establish themselves in the field.

As a result a lot of research output now produced is increasingly targeted at improving publication records rather than contributing to the advancement of the field or society.

This culture, in which research increasingly resembles a self affirming assembly line has also resulted in the proliferation of ‘predatory journals’ which are entirely antithetical to the scientific process.

So how then can the quality of scientific research be measured? Perhaps an index of the efficiency of use of research funds can be introduced? Or an index of the level of effort and ingenuity applied in the research?

What is clear, is that capitalist, competitive, derivative, output based indices of research quality are inadequate, and inversely affect the efficiency of the scientific process.

Too often aspiring researchers are forced to compromise their ideals, using public funds to produce publications to advance their careers, rather than the field their passionate about.

To encourage young researchers, and to ensure the quality of scientific research as competition for funds continues to increase, the association of the quality of the researcher with the amount of publications she/he produces needs to stop.

Some of my sentiments are mirrored somewhat by the Slow Science movement, which I found in researching this article. According to their website, the society based in Berlin (I know, where else?) emphasises the need for scientists to take their time. Their manifesto quotes, ‘Society should give scientists the time they need, but more importantly, scientists must take their time.’

I agree. Scientists need to be given the time, and opportunity, to think. And not to produce publications on an assembly line.