It’s actually quite clear what a settlement is, isn’t it? The Neolithic period is defined precisely by sedentary lifestyles and agriculture. So when an archaeological site yields the remains of houses, a whole series of assumptions spring to mind: the people were farmers. They were settled. Linked to this are further, often unconscious thoughts. For example, that a farmer would not lightly abandon his fields, and that this applies to all farmers in a village. Consequently, we assume the existence of stable communities over extended periods. The first shock came in the 1990s, when dendrochronology began to show that settlements on lakeshores and in the moors were often very short-lived. Some settlements lasted only 15 years, others as few as eight. Only recently have voices within the research community grown louder, suggesting that our understanding of settlements is too heavily influenced by the Middle Ages and that prehistoric reality may have looked different. More and more settlements are being discovered that do not fit the image of a farming village. Be it because there is no good arable land in the vicinity; be it because there was only room for a single house on a sandbank; be it because the finds point to specialised hunting, fishing or textile production, but provide no convincing evidence of traditional farming. There is therefore much to suggest that some sites were used only for specific seasonal activities, such as fishing at certain times of the year during fish migrations.

The ‘Küsnacht-Immensee Dorfplatz’ village square site in the canton of Schwyz is an interesting new case because it is situated on the shortest and most efficient land route between the waterways of Lake Zug and Lake Lucerne. The finds consist predominantly of the remains of the production of semi-finished products for stone axes made from serpentinite. This is a green stone found only in the Alps, but it was a popular raw material for stone axes throughout the wider Alpine foothills. One of the few economic routes from the quarries to the end users runs precisely via Immensee. And yet the settlement did not specialise in the production of axes, as the remains and tools associated with the final production stage from these semi-finished products are far too rare. Such finds have been made in other settlements. Thus, only semi-finished products were produced in Immensee and transported onwards, which leads us to the question of whether the Late Neolithic economic system was already characterised by such a division of labour that a community could sustain itself on it in the long term. The alternative would be that people only came to Immensee occasionally – for example, to set off for the quarries and, on the return journey, to process the quarried stones into semi-finished products in order to reduce the weight of the load. In that case, the question arises as to whether any farming was carried out locally at all, or whether crops were brought along as provisions. If herds were kept locally, were only a few animals brought along as provisions? All of this leads us to ask more far-reaching questions: Was it actually a single community that used this site? Or was it a meeting place for people from different communities who shared the same goal? Did the people here merely exchange serpentinite, or did they also settle other matters – such as disputes?

Immensee could represent an entirely new category of archaeological site. We therefore wish to investigate whether humans reshaped the environment in the same deliberate way as we have reconstructed in Zurich, or whether we can identify a new type of human–environment relationship. We aim to reconstruct what was produced and consumed locally. We want to know whether people, animals and supplies came from further afield. In this way, we are examining a hitherto misunderstood aspect of the Neolithic period in greater detail, in order to better answer one of the seemingly simplest questions: what, in fact, is a settlement?

In archaeology and heritage conservation, the only constant is change. Technological development continues to accelerate and is having an impact on processes – including in heritage conservation. At the same time, the academic landscape is changing. Last but not least, the questions being asked in archaeological research are also changing. Whereas, for example, in the 1980s we were still wondering what farming was like in the era of the pile-dwelling settlements, this is now quite well understood for the Late Neolithic. However, there are still gaps in our knowledge regarding most other periods. 

All this suggests that, in the future, we will not be able to operate according to today’s (or yesterday’s) ‘best practice’ if we wish to make the best use of scarce resources. Anyone who has ever found themselves in a situation where new technologies would be helpful or even essential for a specific project knows that by then it is too late to try to integrate them into the processes. This must be done well in advance.

So when we ask ourselves what the future of underwater heritage conservation might look like, we need to answer a series of questions:

• Which issues are relevant now and are likely to be relevant in the near future?
• Which methods provide data that is important for these questions?
• What kind of samples are needed, and in what quantities?

In an ideal world, one could use a boat and a sediment sonar (or another geophysical device) to create a 3D model of the archaeological layers beneath the lakeshore and map the locations of the houses based on the signatures of the building clay. After sampling the pile field, one could date the layers and buildings using dendrochronology. And then comes the key part: using a sediment drill, one could extract targeted and minimally invasive samples of the archaeological layers from the individual buildings. The monument would remain intact – and yet, without an excavation, one could provide university researchers with precisely the samples they need to generate a large quantity of relevant data. This would be the ideal combination of fulfilling the heritage conservation mandate – creating an archive of monuments – whilst exercising maximum restraint and cost-effectiveness.

This ideal scenario is by no means unrealistic. In underwater archaeology, data from minimally invasive drilling is already available at many sites, providing a good basis for 3D models. There are also projects aimed at further developing geophysical detection and modelling of strata – even if there is still much to be developed in this area. Dendrochronology is, in any case, a standard application. What is still missing is a thorough review of current analytical methods: 

In recent years, sediment genetics has made great strides. But it has never before been applied to organically preserved cultural layers. What new insights can it contribute to the range of bioarchaeological disciplines? Does it raise new questions? For example, regarding the population genetics of the inhabitants of lakeside settlements where human remains are so scarce? How much sample material is required for this? How must it be collected, packaged and stored in order to realise its potential? Where do the various disciplines complement each other most effectively? These questions naturally arise all the more when one considers rescue excavations, where large quantities of sample material can be recovered. What does optimal cooperation between the various disciplines look like? What does this mean for future best practice in heritage conservation?

If we want to be prepared for future challenges, we must develop the necessary methods now. The DeciLak project is dedicated precisely to this methodological development within the field of interdisciplinary bioarchaeology. That is why, additionally to the WEAVE funding, it is also supported by the Zurich Cantonal Archaeology Department and the Schwyz Office for Culture.

• Were the Neolithic lakeshore communities in the northern alpine foreland as autarchic and sedentary as traditional models suggest? Or were they highly mobile in the course of a year engaging in different seasonal economic activities in different places? In other words: Was the Lakeside Neolithic a low-level food production economy in the sense of Bruce Smith (2001)? 
• Who lived in the houses in the lakeshore settlements and how far can we get in identifying the inhabitants genetically?
• Who lived in the houses in the lakeshore settlements and how far can we get in identifying the inhabitants genetically?
• How can underwater monument preservation in the middle 21st century reconcile the needs of monument preservation and relevant research?