 My name is Javier with PEDET and I am a PhD student in Amazonia and Archeobotany at the CASES Research Group in the University of Pumpeu-Fabra here in Barcelona. And I'm going to briefly present the project we are carrying out in the Yanos de Mojos, southwestern Amazonia. The increasing discovery of numerous pre-Columbian settlements in the Amazonia has led archaeologists of the Lowland Neotropics to question how ancient societies adopted to this biome and what was the impact on the landscapes resulting from their activities. Archeological evidence for complex agricultural societies has been found in many areas of the Amazon basin. The large amount of heterogeneity of the archaeological remains such as earthworks in southwestern Amazonia or the famous anthropogenic dark earths along the coasts of major Brazilian rivers constitute a testimony of the cultural diversity that characterized the Amazonia and the level of landscape transformations carried out by generations of people. Indeed for some researchers this is the reason why Amazonia should be considered as a domesticated landscape. The Yanos de Mojos where we are investigating is located in the Lowlands of Bolivia. It's a huge food savanna of circa 150,000 square kilometers where patches of river in the valley forest appear interspersed. The Yanos has an impressive archaeological landscape characterized by the great variety of earthworks such as monumental mounds, race fields, canals, coastways. All of them made by pre-Columbian late olosin agrarian societies that greatly modified their landscapes. For example recently it has been calculated that in the Yanos there are about 550 square kilometers of race fields and now we know that they were used to cultivate maize and many of them. However the presence of pre-Columbian populations in this territory leads back to early olosin times. Another type of earthworks is widely scattered across the Yanos. Those race patches of forest that you can see in this picture which are used as a circular are called forest islands. There are hundreds in the Yanos and the excavation of one of them revealed that it is a prehistoric artificial mound made by early to mid olosin hunter-gatherers and then it was reoccupied by agricultural populations of late olosin. This excavation was carried out at Isla del Tesoro. It showed a first occupation which spans from about 10,500 years to 4,000 years before present. The people who inhabited this area at this time were hunter-gatherers that made a shell midden obviously by the consumption of snails although they also for example hunted mammals or catch fish. Then the site was abandoned and it was reoccupied approximately until the arrival of the Europeans to South America by a group or groups that apparently were no longer involved in hunting and gathering activities and that otherwise were producing cell pottery, reason why we interpreted them as agricultural groups. Well this finding stimulated new questions about forest islands. How many of them are of actual anthropic origin? What is their general chronology? Which way do societies that build them? And how did they subsist? This is why we decided to visit another area of the Yanos where forest islands are also present to do a survey and an archaeological excavation. We choose the Barbazul Nature Reserve where we within 100 hectares there are 24 forest islands and hundreds of pre-Columbian red fields sometimes found in association with some of the islands. We visited 19 of these 24 forest islands and all of them have high concentrations of organic rich sediments, wood charcoals, burnt earths and pottery so all of them are anthropogenic. Then we excavated one of those islands locally known as Islamanechi. It's a huge settlement located next to a paleo channel and has raised fields in its surrounding. There we also identified two main phases. The oldest one is from early Olesin at around 10,000 years before present and it's a layer of extremely compact burnt earths with large presence of charcoals. Although the occupation was of really short duration, unfortunately we did not find any other evidence to help us understand what kind of occupation it was. Then there is an Iatus of about 5,000 years after the first phase and the site was occupied during 2,000 years between circa 5,000 years and 3,000 years before present. This layer corresponds to an occupation of people who produced pottery and cultivated squash and maize as shown by the phytolith analysis I created out from sediments. It's interesting because unlike Isla del Tesoro, Islamanechi is not a shell midden and on the other hand the ceramic phase is much longer with the early Olesin phase, while the early Olesin phase is much shorter. Moreover, while Islamanechi is surrounded by raised fields, Isla del Tesoro doesn't. As we have seen in First Islands, we're home of hunter gatherer and agriculturalist populations in the Bolivian Amazon during the Olesin. All results show that these sediments were made by different groups that exploited different resources at different places and chronologies. So First Islands are long term archives of human occupations key to better comprehend the degree of land use that Southwestern Amazonia has supported during several thousands of years as a result of the economic and cultural activities carried out by the pre-Columbian Indians. What they present is the result of preliminary investigations but further research on Forest Islands is required to fully reconstruct land use practices in this particular region of Amazonia. We need to confirm for example how many Forest Islands are anthropogenic if some of them are natural and given the dissimilarity of the two islands investigated that they show you. We also need to delve into what kind of subsistence strategies were practices by the inhabitants of the islands or which of these sites were built and are occupied at the same or different times. Thank you very much for your attention.