Sunday, 17 August 2014

Fieldtrip to the Bolivian lowlands

In this post I am going to upload photos and short comments about the ongoing fieldtrip to Beni, Bolivia, of the MSc students from the Institute of Geography at Bern University. The students arrived in Trinidad the 11th of August and will leave on the 21st.

Day 1 - 11th of August. Visit to the Museum Kenneth Lee in Trinidad.

Day 2. Excursion to the Mamoré river

Leaving the port
Describing and sampling a paleosol sequence outcropping along the Mamoré River bank

Day 3. Visiting the Indigenous community of Bermeo
Before playing football...

...and, with a BFC like outfit, Bermeo won :-)
Day 4 and 5.Community of Ibiato, on a paleo levee-backswamp of the Grande River
Excavating and analyzing a transect of 5 soil profiles along a paleo Grande River lavee-backswamp catena.
. Day 6. Meeting with indigenous leaders and visiting experimental raised fields
Doña Berta Vejarano Congo, leader of the indigenous march against the construction of the road across the TIPNIS indigenous territory and natural reserve, and Pedro Nuny Caity give a talk about the political situation of the indigenous people in the Bolivian Lowlands under the government of Evo Morales
Visiting experimental raised fields built by Oxfam GB in a suburb of Trinidad, now managed and subsidised by Trinidad City Council 
Day 7 - Sunday, day off at Laguna Suarez, one of  the many rectangular and oriented lakes found in the Bolivian Amazon.
Laguna Suarez, about 5 km from Trinidad

Day 8 - In the the morning visit to the Estancia La Chachra, where we learned about the extensive cattle ranching that is practiced in the Beni. We also went on a little safari.
Selecting the cows by size and checking if they are healthy

A little safari along the road inside La Chacra

One of the many alligators living in La Chacra, in the ponds that were excavated to take the material used to build the road 
In the afternoon we went to visit on of the biggest pre-Columbian monumental mounds: El Cerrito
Our guide invited us to have toronjas (a kind of sweet grape fruit) on the way back from the mound
Day 9 - Visiting the indigenous community of San Miguel del Matire and the CIPCA cacao project
Olver Vaca from CIPCA explains to us how the cacao project works

Visiting the facilities in San Ignacio the Moxos where the indigenous cacao is processed
Day 10 - Last day - We went fishing in the Mamoré
Fishing from the boat with "lineada y anzuelo"
The fish we caught
Preparing the fish at the restaurant "La choza del Pescador"
And ready to eat!!

This is the end of the 10 day field trip in the Beni - Bolivia. I hope you enjoyed it! See you in Bern!!

Friday, 17 January 2014

“Predicting pre-Columbian anthropogenic soils in Amazonia” “Predicting pre-Columbian anthropogenic soils in Amazonia” is the title of a recent paper by McMichael et al. published in Proceeding of the Royal Society B. It is not open access but you can read the abstract here. In this paper McMichael et al. present a predictive model for the presence of Terra Preta in Amazonia.  The model predicts the likelihood of finding Terra Preta sites in any given spot within Amazonia.  In general, I liked the idea behind the paper. These models give us an objective basis for further research and discussions. It is thanks to this kind of work that we can go beyond subjective views about the extent of human impact in pre-Columbian Amazonia and start to formulate hypothesis that, through survey and measurement, can be later tested. The first important result of this paper is that, given the data available, we can now estimate that terra preta is likely to be found only in a 3.2% of the forested areas of Amazonia. This is far less than other previous estimates (Erickson, 2008).

However, I find the discussion of McMichael et al. a bit disappointing with regards to two points. The first is the meaning they give to the presence of terra preta; the second is the reasons they give to explain the absence terra preta outside of Brazil.
What is terra preta? Is it the result of permanent settlement where people cooked and dumped food remains for centuries, eventually causing the enrichment of the soil in with charcoal, phosphorous, organic matter and the rest of elements used to define terra preta? Or is it the result of soil management techniques aimed at improving fertility and agricultural potential? McMichael et al. seem to imply that terra preta is the latter: the result of soil fertility enhancement. They say: “The lack of terra pretas in western Amazonia may be because the Andean-derived soils of western Amazonia did not require nutrient enrichment… [the bold is mine]”. However, this kind of interpretation of terra preta being the result of Pre-Columbian agricultural intensification has been challenged by many authors. Neves & Petersen (2006) discovered that at the Hatahara occupation site (close to Manaus) pre-Columbians actually used terra preta to build burial mounds, which is a strange use for an agricultural soil that took centuries to form. Of course, we cannot exclude that pre-Columbians took advantage of the fertile terra preta for their gardens associated to their homes; in the same way that they could have taken advantage of the fertility of pre-existing middens (see Arroyo-Kalin, 2012 for a discussion on this).But this does not mean that people intentionally created terra preta for agriculture!
Recently, Glaser & Birck (2012) concluded their review about the state of the scientific knowledge about the properties and genesis of Anthropogenic Dark Earths in Central Amazonia saying: “there is no scientific evidence indicating that forgotten agricultural techniques for large scale soil fertility improvement are responsible for terra preta genesis”. 

This leads us to my second concern: what does it mean when no terra preta is found? Here, McMichael et al. suggest that the lack of terra preta indicates that people decided to produce food in some other way, due to cultural and/or environmental reasons. They say: “[In the Llanos de Moxos] instead of terra preta formation, large societies sustained themselves by using techniques such as fish weirs and raised-field agriculture”. But, is it cultivating little gardens that large societies sustained themselves? I think the answer is no. In fact, pre-Columbians living in terra preta sites performed agriculture in the surrounding area, eventually forming terra mulata sites. Terra mulata sites are far larger than terra preta ones. Terra mulata sites do not contain pottery and are far less fertile than terra preta ones, but still, they are richer in organic matter than the normal Amazonian oxisols (more on this here). It is terra mulata that formed because of ancient agricultural use, not terra preta.
The main problem we face when tackling the question of terra preta is its definition. The definition that is generally given to terra preta coincides with the description of the geochemistry of a midden (From Wikipedia: an old dump for domestic waste which may consist of animal bone, human excrement, botanical material, vermin, shells, sherds, lithics, and other artifacts and ecofacts associated with past human occupation) and there are middens everywhere in the world! As a consequence of this, terra preta sites are now appearing everywhere... We should also keep in mind that the whole terra preta concept is rooted in the context of the big surprise that the first researchers had when they found black organic sediments in the middle of Amazonian heavily weathered soils. In fact, terra preta is often defined (and mapped in the field) in relation to the surrounding soil (Fig. 1). In my view, there is not much that actually differentiates terra preta from other occupation horizons elsewhere. I have seen several places in the Bolivian Amazon that, because of the colour of the soil, concentrations of P, Ca, charcoal etc., would fit quite well into the definition of terra preta (see for example this). It is just that they are not called terra preta, yet :- ). It could be that the absence of terra preta sites outside Brazil is merely the result of researchers giving these kinds of soils/deposits different names in different regions, such as “middens” or “occupation horizons”.

Figure 1: oxisol left, terra preta right (from Wikipedia)
I think that the, otherwise excellent, paper by McMichael at al. could have benefited from incorporating into their model a database of terra mulata sites, instead of terra preta sites. Or, even better, if they had used a database of pre-columbian occupations, including the archaeological sites known outside of Brazil. This would have provided a more reliable tool for modelling pre-Columbian agriculture (if a terra mulata database had been used) or settlements patterns (if a database of archaeological sites had been used) within the Amazon basin; and for modelling pre-Columbian disturbance of the natural environment.

 McMichael CH, Palace MW, Bush MB, Braswell B, Hagen S, Neves EG, Silman MR, Tamanaha EK, & Czarnecki C (2014). Predicting pre-Columbian anthropogenic soils in Amazonia. Proceedings. Biological sciences / The Royal Society, 281 (1777) PMID: 24403329

Erickson, C.L. (2008). Amazonia: the historical ecology of a domesticated landscape In: H. Silverman, W.H. Isbell (Eds.), Handbook of South American archaeology. Springer, Berlin, pp. 157-183 DOI: 10.1007/978-0-387-74907-5_11

Neves, E.G., & Petersen, J.B. (2006). Political economy and pre-Columbian landscape transformations in Central Amazonia In: W. Balée & C.L. Ericksonl (Eds.),Time and complexity in historical ecology. Columbia University Press, New York, pp. 279-309

Arroyo-Kalin, M. (2012). Slash-burn-and-churn: Landscape history and crop cultivation in pre-Columbian Amazonia Quaternary International, 249, 4-18 DOI: 10.1016/j.quaint.2011.08.004

Glaser, B., & Birk, J.J. (2012). State of the scientific knowledge on properties and genesis of Anthropogenic Dark Earths in Central Amazonia (terra preta de Índio) Geochimica et Cosmochimica Acta, 82, 39-51 DOI: 10.1016/j.gca.2010.11.029

Tuesday, 3 September 2013

The rectangular and oriented lakes in the Bolivian Amazon are not tectonic, and now what?
Our latest paper has been published a few days ago in Geomorphology. The title is: "The origin of oriented lakes: Evidence from the Bolivian Amazon". Here goes a very short version of it.
The presence of hundreds of rectangular and oriented lakes is one of the most striking characteristics of the Llanos de Moxos landscape (Fig. 1). Many different mechanisms have been proposed for their formation, including subsidence resulting from the propagation of bedrock faults through the foreland sediments, scouring caused by large-scale flooding, paleo deflation combined with wind/wave action and human agency. Nevertheless, amid this diversity of hypothesis, the most commonly accepted cause of lake formation to date has been tectonics.
Figure 1. Landsat image of oriented and rectangular lakes in the Llanos de Moxos
Plafker’s tectonic model (Fig. 2) has never been tested. If faulting is involved, the displacement should be visible and measurable through sediment profiling. The only element needed is a stratigraphic marker that allows the measurement of the vertical displacement.
Figure 2. Tectonic model for lake formation (Plafker, 1967). According to Plafker, the lakes' rectangular shape results from the propagation of bedrock fractures through unconsolidated sediments.
Thanks to our recent discovery of a paleosol below mid-Holocene fluvial sediments in the south-eastern LM (Lombardo et al., 2012), where several lakes are found, it is now possible to test the tectonic hypothesis. If lakes were formed by local subsidence induced by bedrock faults, we should find the paleosol at a greater depth below the lake than in the area surrounding it. 

This is how we cored the lakes
Stratigraphic profiles from transects that cut across the borders of three lakes show otherwise (Fig. 3): the depth of the paleosol is the same. Hence, tectonics, as the mechanism behind the formation of the lakes, can be ruled out. The origin of the Moxos rectangular and oriented lakes is still very much unresolved. A more detailed discussion about the possible mechanisms behind the lakes' formation can be found in Lombardo & Veit (In Press)
Figure 3. Stratigraphic transects from the outside to the inside of the lakes. Dotted white lines define the lakes’ basins. The early to mid-Holocene paleosol acts as a stratigraphic marker (see Fig. 2). Cores 52, 63, 81, 170, 205 and 210 provide the reference depth of the paleosol outside the lakes; cores 77 and 204 have been performed in areas of the original lakes’ basins that have been infilled; cores 78, 169, 171 and 209_b come from inside the lakes. Continuous black lines reconstruct the original lake bottom (previous to lacustrine infilling); dashed black lines connect the paleosol. Source of digital images: Google earth.
Lombardo, U., May, J.-H., & Veit, H. (2012). Mid- to late-Holocene fluvial activity behind pre-Columbian social complexity in the southwestern Amazon basin The Holocene DOI: 10.1177/0959683612437872
Lombardo, U., & Veit, H. (2013). The origin of oriented lakes: Evidence from the Bolivian Amazon Geomorphology DOI: 10.1016/j.geomorph.2013.08.029
Plafker, G. (1964). Oriented Lakes and Lineaments of Northeastern Bolivia Geological Society of America Bulletin DOI: 10.1130/0016-7606(1964)75[503:OLALON]2.0.CO;2

Saturday, 31 August 2013

Amazing media response to our latest paper in PloS ONE

Our paper “Early and Middle Holocene Hunter-Gatherer Occupations in Western Amazonia: The Hidden Shell Middens” has been published less that 3 days ago in PLoS ONE. It was included in the press release of PLoS ONE and, once the embargo expired, we produced two other press releases (see previous post).
I am amazed by the interest that media from all around the world have shown! Till now I have counted more than 50 articles from USA, Spain, Germany, Brazil, Bolivia, Russia, Australia etc. Plus, several people posted about our research in their blogs.
Samples from the internet press of the last 2 days:

A blog post I liked:

Thursday, 29 August 2013

The Hidden Shell Middens - Press releases

Here two media releases, one in English written by Kat and the another in Spanish written by José, about our latest paper "Early and Middle Holocene Hunter-Gatherer Occupations in Western Amazonia: The Hidden Shell Middens" published in PLoS ONE the 28th of August 2013.

Traces of the earliest inhabitants of Bolivian Amazonia hidden in plain sight
The enigmatic ‘forest islands’ set amidst the grasslands of Bolivian Amazonia have yielded the earliest evidence of human habitation in the region.   Previously thought to be relict landforms cut away by shifting rivers, or long-term bird rookeries or termite mounds, these piles of freshwater snails, animal bones and charcoal are now known to have been built up over millennia, starting from at least 10,400 years ago, by ancient hunter-gatherers. 
Using novel approaches drawn from archaeology, geomorphology and geochemistry, an international team of researchers, led by Dr. Umberto Lombardo of the University of Bern, has conducted detailed excavations of a large mound known locally as Isla del Tesoro (Treasure Island).  Distinctive chemical signatures of human presence were recorded at high levels throughout the mound sediments, and studies of the animal bones and shells indicate they are the remains of ancient human meals.  Isla del Tesoro tells us that from over 10,000 years ago, hunter-gatherers were moving across the grasslands hunting a variety of mammals, catching fish and birds, and gathering large quantities of freshwater snails.
 Over time, the refuse of these hunting and gathering forays built up forming mounds which sat elevated above the floodplain.  These refuse or ‘midden’ mounds in turn provided a habitat for local plants and animals, transforming them into the forest islands so recognisable in the landscape today.  It is highly likely that many more midden mounds lie buried beneath the metres of silts under the current savannah.
Regularly flooded savannah landscapes such as those surrounding Isla del Tesoro have long been thought to be an inhospitable environment for early hunter gatherers.   The densities of animal prey are lower and less predictable than in coastal areas, near stable watercourses or in forested areas where early South American archaeological sites are typically found.  Lombardo and colleagues’ work at Isla de Tesoro tells us that early South Americans moved across a wider variety of landscapes than previously thought, and adapted their ways of life to cope in these challenging environments.
Paper details
Lombardo, Umberto1, Katherine Szabó2, Jose M. Capriles3, Jan-Hendrik May2, Wulf Amelung4, Rainer Hutterer5, Eva Lehndorff4, Anna Plotzki1, Heinz Veit1. 2013.  Early and middle Holocene hunter-gatherer occupations in Western Amazonia: the hidden shell middens. PLOS ONE.  Online from 28th August, 5.00pm (EDT)

1 University of Bern, Switzerland
2 University of Wollongong, Australia
3 University of Pittsburgh, USA
4 University of Bonn, Germany

5 Alexander Koenig Zoological Museum, Bonn, Germany

Conchales ocultos revelan milenaria presencia humana en la Amazonia boliviana

Un equipo internacional de investigadores, dirigido por el Dr. Umberto Lombardo, de la Universidad de Berna – Suiza y que incluye al arqueólogo boliviano, Dr. José M. Capriles, acaba de publicar en la revista científica de acceso abierto PLoS ONE, un estudio que documenta la existencia de asentamientos humanos en la Amazonía boliviana desde al menos 10.400 años atrás. En esta región se atribuía la ausencia de ocupaciones pre-agrícolas a condiciones ambientales desfavorables. Sin embargo, esta investigación multidisciplinaria combinó información de arqueología, geomorfología y geoquímica, para identificar restos de asentamientos de cazadores-recolectores en islas de bosque” o “islas de monte” en los Llanos de Moxos del Departamento del Beni. Los autores de la investigación informan que tres de estas islas son conchales o montículos formados por conchas (además de huesos, tierra quemada y carbón) desechados por grupos de cazadores-recolectores móviles. Análisis de radiocarbono indican que estos grupos se establecieron en la región a principios del Holoceno, es decir, hace aproximadamente 10.400 años y que mantuvieron su modo de subsistencia varios milenos. Las islas de bosque estudiadas parecen haber sido abandonadas hace aproximadamente 4000 años atrás para luego ser reocupadas poco antes de la conquista española por las sociedades agrícolas que construyeron las lomas y camellones del Beni. Esta investigación permite confirmar que la Amazonía boliviana estuvo poblada por seres humanos mucho más antes de lo imaginado y que sus pobladores fueron agentes activos en la formación del paisaje.


Umberto Lombardo, Katherine Szabo, José M. Capriles, Jan-Hendrik May, Wulf Amelung, Rainer Hutterer, Eva Lehndorff, Anna Plotzki & Heinz Veit. 2013. Early and Middle Holocene Hunter-Gatherer Occupations in Western Amazonia: The Hidden Shell Middens. PLoS ONE Vol. 8, No. 8, pp. 1-14. E72746.

Esta publicación es resultado del “Proyecto de Investigación Arqueológica: Ocupación Humana, Paisajes Antrópicos y Cambio Medioambiental durante el Holoceno en los Llanos de Moxos – Amazonía Boliviana” que cuenta con el apoyo del Viceministerio de Interculturalidad del Estado Plurinacional de Bolivia, la Gobernación del Departamento del Beni, la Fundación Nacional de Ciencias Suiza y otras institucionales internacionales y nacionales.

Monday, 7 January 2013

The diffusion of unsuccessful innovations: the myth of raised field agriculture
Pre-Columbian raised field agriculture is an extremely interesting topic that we have discussed in this blog before, here, here and here. We call raised fields “any prepared land involving the transfer and elevation of soil above the natural surface of the earth in order to improve cultivating conditions” (Denevan and Turner, 1974). Raised fields have received a lot of attention in studies related to pre-Columbian demography. They have been considered key in allowing dense populations of complex societies to inhabit seasonally flooded regions of South America in pre-Columbian times. Beyond their academic interest, raised field agriculture has also become popular among rural development workers and aid agencies working with small farmers in South America. For more than 30 years now, some archaeologists and NGOs have favoured the “re-introduction” of this pre-Columbian agricultural technique among modern day farmers. In their view, raised fields (which are considered analogous to the Chinampa system in Mexico) represent a promising pro-poor agricultural innovation which is more productive and sustainable than traditional agriculture (which, in the neo tropics is, basically, slash and burn).
A few days ago, Philippe C. Baveye published on-line a thorough debunk of such proposals  (Baveye in press) . It is a comment to a paper by Renard et al (Renard et al., 2012) where the authors advocate for the adoption of raised fields agriculture among modern farmers. The main points that Baveye puts forwards are: 1) There is no evidence that raised fields have supported dense populations in the past; 2) the pre-Columbian Chinampa system is unique. Therefore, it cannot be assumed that the productivity of the South-American raised fields, which are very different from the Mexican Chinampas, was comparable to that of the Chinampas; and 3) the purpose of raised fields was limited to water management:  soil drainage and/or irrigation. We reach very similar conclusions in (Lombardo et al., 2011). It is important to highlight that none of the projects designed to reintroduce raised field agriculture among small farmers in Bolivia and Peru have ever worked (actually, I am not aware of any successful rehabilitation anywhere in the Americas). Local farmers have no idea or knowledge about this ancient practice: this kind of indigenous knowledge was lost hundreds of years ago when the Spaniards got to America. Therefore, besides the technical problems described above, another reason behind this large scale failure is that raised field agriculture has been entirely “invented” by archaeologists and NGOs: the latest example I know of raised field rehabilitation project failures comes from an Oxfam project in the Beni - Bolivian Lowlands. The picture below shows the current state of the raised fields built by Oxfam in 2009, amid an important media coverage and support (for example, see this BBC article).

In 2011 raised fields were also built in the northern Beni.You see the state of the fields during the summer 2012 (photo below).

Hopefully, Baveye’s comment will contribute to make researchers more cautious before proposing the ‘reintroduction’ of raised field agriculture in rural communities.

Baveye, Philippe C. (2013). Comment on “Ecological engineers ahead of their time: The functioning of pre-Columbian raised-field agriculture and its potential contributions to sustainability today” by Dephine Renard et al Ecological Engineering

Denevan, W. M., and Turner, B. L., 1974, Forms, functions and associations of raised fields in the old world tropics: Journal of tropical geography, v. 39, p. 24-33.

Lombardo, U., Canal-Beeby, E., Fehr, S., & Veit, H. (2011). Raised fields in the Bolivian Amazonia: a prehistoric green revolution or a flood risk mitigation strategy? Journal of Archaeological Science, 38 (3), 502-512 DOI: 10.1016/j.jas.2010.09.022

Renard, D., Iriarte, J., Birk, J., Rostain, S., Glaser, B., & McKey, D. (2012). Ecological engineers ahead of their time: The functioning of pre-Columbian raised-field agriculture and its potential contributions to sustainability today Ecological Engineering, 45, 30-44 DOI: 10.1016/j.ecoleng.2011.03.007

Wednesday, 19 December 2012

Trinidad 2013?

The Llanos de Moxos, in the Bolivian Amazon, are a fascinating site. Full of archaeological remains, striking and diverse tropical fauna and flora and many indigenous cultures. The Llanos covers about 150.000 km2 of seasonally flooded savannah. For many years it has been largely neglected by the scientific community, only a handful of researchers have worked in the area. Fortunately, things are now beginning to change. In the last half a decade several new researchers (including myself) have decided to study this fascinating region. As far as I know, there are now several ongoing research projects in the LM. I list here those that come to mind:

A few weeks ago, whilst reading a post on John Walker’s blog, I thought it would be great if we could all meet next summer in Trinidad,Beni. Actually, Last year I already talked about organising some kind of meeting among the ‘Moxos researchers’ with Marcos Michel, currently Director of la Direccion General de Patrimonio Cultural of the Bolivian Government, and with other people from the Governación del Beni, and all seemed very keen with the idea. It would be great to share some of our work and experiences among ourselves, but also among local researchers and interested parties. There are plenty of Benianos who are passionate about the  past of the LM and some areperforming their own research (such as Ricardo Bottega in Trinidad or Jaime Bocchetti in Santa Ana de Yacuma). It could be really interesting to engage in an exchange of ideas and experiences between “cientificos gringos” and Bolivianos!
If you like the idea and want to get involved you could do 2 things: 1) if you know of other ongoing projects in the Llanos de Moxos you could send the link of this page to those involved and send me their names (so that I can add them to the list). 2) Let me know when would be the best time for you to have the meeting in Trinidad, considering that it would have to be during the dry season (June-October). Keep in mind that there is a conference on Amazonian archaeology in Ecuador from the 7 to 14 of September, so we should avoid overlapping. Although I am not entirely sure if the conference has been confirmed.
Cheers, and I hope to see you in Trinidad next summer!