Pre-Columbian human history in the Amazonia remains disputed

This month two contesting papers have been published on the question how pre-Columbian society in the Amazon looked like. One is from Piperno et al. in The Holocene and the other one is from Clement et al. in Proceedings of the Royal Society. Both are putting forward an alternative to the now-abandoned concept of a ‘virgin’ Amazon. Previously, is was believe the Amazon rainforest was a pristine untouched wilderness before European settlers came over. The discovery of so-called ADE (Amazonian Dark Earth), prehistoric geometric ditches and the preposition of certain plant concentrations being a relic of prehistoric management led researchers to the conclusion that the region has actually been relatively densely populated. In 2013, Stéphan Rostain wrote an interesting book on the topic called Islands in the rainforest.


Ditches of old settlements found in Acre state, Brazil (from Rostain, 2012).

Today, researchers are divided.

Clement et al. explain all archaeological sites as a connected system. Densely populated regions were found along the rivers, which also spread along smaller tributaries and locally in between rivers. They describe the region as a social-ecological mosaic landscape with production systems. The lack of more archaeological evidence in the dense forests is due to its large area and its remoteness, rather than the preposition nobody had lived there. Instead, they state the current findings actually proof these regions might as well be full of undiscovered man-made features.

On the other hand, Piperno et al. is trying to urge for caution in proposing wild hypotheses and stresses that the present archaeological findings are still open for interpretation and rather local, not at all wide-spread. They acknowledge a much higher population number before the arrival of Europeans and also propose large communities along the main rivers, but not much more. The press seemed to pick up more on the paper of Clement et al.

Archeological sites

Locations of pre-Columbian settlements (from Clement et al., 2015)

p.s. That same week, the press picked up on related news from the Amazon in genetics. The tribes living in the Amazon for millennia seem to be closely related to Australasian people (Australian and Papuan indigenous people). The discovery of Skoglund et al. is, just as the research of Piperno et al. and Clement et al., breaking with the well-established theories. Until now the roots of native Americans have been believed to come from Eurasians crossing the Bering street during the end of the Ice Age. These wanderers then moved south. The new research shows it might have been a little bit more complex back in the days. Who were / are the Amazonian tribes?

Reasoning Conservation: Prudence, Justice and the Good Life

This week I had the pleasure of attending a lecture by Uta Eser on the PopeWHY of nature conservation. It seems a stupid question in our field of research and is actually seldom questioned. Moreover, even the pope is fighting climate change nowadays! The story on climate change and extinction of species is well-known. The facts are known. However, there is often an implicit task in this story: an urging plea to do something about it. For action nevertheless, one needs to rationalize and justify why the facts are worth doing something about.

Uta Eser discussed that the rationality of protecting nature, biodiversity and traditional landscapes can be divided in three pillars: Prudence (Intelligence), Justice and the Good Life (Happiness).

Prudence has been mostly used and is referring to the existential need for nature; it serves us in the basic needs to survive. In communication, one often uses the picture of the guy sawing the branch on which it is sitting: you must be out of your mind to saw the very branch which is supporting you! The analogy holds for the sustenance and insurance of the human inhabitants of planet earth. One could think of the scientific approach on ecosystem services and its (monetary) value. However, we get into a pitfall: the collective WE does not always have the same values and wishes as the individual WE. The WE is becoming a generalization and its rhetoric is concealing important issues.Branch

Justice is the second pillar and one of these issues. It might help to redeem the pitfall of prudence. Justice is looking at who is sawing the branch and who will fall out of the tree when the branch is cut. It goes without saying that industrialized western countries are very active in handling the saw, mostly indirect. Our needs (USA is needing 4 planets, while India is needing 0.4 planet!) are being supplied by developing countries, where resources and cheap labour are available. Their branch is being sawed through (think of oil palm plantation, open pit mining and oil exploitation in the Amazon to name a few). In a broader spectrum one could also call upon human being within the chain of living species (biodiversity) or the future generation, who will not have much left over from planet earth. What is justifying us to exploit its resources in such a way? This justification is also used by the pope. However, justification gives us an obligation and people start to rethink the thesis and actually question whether we really need all this nature to survive as a species.

At this point the third pillar comes in: Happiness for All. This appeals to our subjective reasoning of feeling good and comfortable. As the Club of Rome stated in 1972, the crux is not whether human species can survive, but whether its existence will be worthwhile. By protecting nature we provide a better life, improving our relation to ourselves, human kind and earth, involving values, ethics and happiness.

More reading?
Eser, Nuereuther, Seyfang and Muller (2013): Prudence, Justice, and the Good Life. A typology of ethical reasoning in selected European biodiversity strategies

Environment, Climate, Humans, Change….

January was cold and grey in Germany. Despite it gave me a bit of fire to dare and challenge some thinking on global changes. Hopefully inspirational… Trying to maybe put the world as we know it into perspective.

Our ancestors in the Ice Age
A few weekends ago, I visited the LVR (Landschaftsverband Rheinland) museum in Bonn, which is currently showing an exhibition on humans living during the final countdown of the last Glacial Maximum, some 15,000 years ago. It gave an amazing picture on the totally different world in Western Europe, compared to what we are used to in the 21st century. Our current forested and agricultural land was a vast savannah, with gigantic animals roaming it.  The human population was less than 10,000 souls and thus had enough food. We wandered around over the floor of the North Sea, where enormous paleo-rivers bursted bewildered over the landscape. However, climate change forced the sea level to rise dramatically, increasing temperatures and rainfall (the 6 degrees lower temperatures fixed much of the available moisture in ice caps). The climate change process made the Europe suitable for forests and thriving plant communities. People gradually became the architects of their surrounding landscape.

Human architects…
A few days later I went to a lecture on the effects of climate change, organised by the Frankfurter Geographische Gesellschaft. My supervisor, Prof. Hickler spoke on the effects related to biodiversity and ecosystems. The IPCC report on the devastating amounts of carbon and other pollutants pushed into the atmosphere was one part. Another part was on the physical effect of human being on the landscape. It reminded me of a recent study, stating that Europe nowadays has more forest than a century ago. In Europe, massive deforestation occurred a few centuries ago, when instead of oil, wood was used as fuel. The landscape was being exhausted and clearcut, something which is happening currently in some tropical countries. The whole ecosystem changed dramatically and large mammals disappeared.

Tropical forests in the climate change century
The two stories came together while reading a somewhat outdated textbook, titled ‘Tropical Forest in Transition’, edited by Johann Goldammer in 1992. This book makes clear that the stable status of tropical rainforest is a fairytale. We want to believe the large Amazon forest has always existed the way we know it nowadays. This is simply not the truth. Climatic changes were not restricted to the Northern latitudes. Incursions of drier savannah landscapes in the transitional forest of the Amazon happened regular and rainforests got a patchy occurrence. Refugia of tropical species surely existed during the ice ages and from here the rainforest developed to its large extent. These refugia could have existed in secluded river catchment, compared to the subtropical forests we find today. Rainforests always existed, but altered. They had to survive paleo-Indians setting fire and huge paleo-El Nino events roaring around the region. The rainforest resided.

The visit to the LVR-Museum, the lecture of the FGG and the insights from Goldammer let me to the following:

  • In the past, climate change has drastically altered the landscape in Northern latitudes, changing a savannah with mega-fauna into a forest without mega-fauna.
  • In the past, humans have drastically altered the landscape in Northern latitudes, deforesting an enormous area, resulting in a destruction of ecosystems.
  • Although tropical forests seem to be relatively stable, it is also subject to frequent environmental changes, showing stages of a more open and patchy landscapes.
  • Currently, we push such large amounts of carbon into the atmosphere that the temperature rises more than the ice age fluctuation.
  • Currently, we are deforesting large extents of forest, similar (and more) to the deforestation in the Northern latitude.
  • Therefore, we can expect alterations in the tropical regions. We probably see ecosystems, which are common today, pushed into refugia, while others take over. This might force us to change our living standards and think once again carefully about system earth we live on.


The geological temperature fluctuations according to the wikipedia site for ‘Geologic Temperature Trend’ (Glen Fergus)