 I'm interested in looking at the environments that our species have merged in and evolved in in Africa and also then expanded into as it moved beyond Africa. In particular one of these that I've focused a lot of my work on is looking at when did humans start moving into tropical forests. These environments are particularly interesting from this point of view because in popular thoughts they're often associated with danger if we think of films such as The Jungle Book or Tarzan. Often there are dangerous animal threats, they're difficult to move through and there's also issues of high humidity that make it very hard to potentially hunt and gather resources in tropical forests. Answering the question when or did our species manage to move into these habitats is particularly interesting to look at how flexible our species is in adapting to different environments and indeed even anthropologists and archaeologists have assumed traditionally that tropical rainforest and tropical forests were not inhabited by our species until very recently. A second related question is that if tropical forests were occupied by our species earlier than we've assumed did our species also modify them at this point. Today tropical forests are some of the most endangered terrestrial environments on the planet after the polar ice caps. They're also crucial to the functioning of our climate system being responsible for the formation of rain clouds and the distribution of precipitation across much of the tropics. They're also crucial in the distribution of heat around the entire planet. Furthermore huge diversity in plants and animals means that they're actually responsible for significant proportions of the world's biological diversity. So trying to understand when our species first started having impacts on these environments, how those impacts have changed through time can potentially give us a significant perspective on how these environments might react to human pressures in the future and how we might come up with better conservation strategies and better ways of using them. So because archaeologists and anthropologists have traditionally neglected tropical forests as viable areas for humans to occupy, one of the first steps has really simply been to investigate them further. Archaeologists and anthropologists have often assumed that things like animal and plant remains that are so crucial to our understanding of what humans were doing at a given time in a given site in the past simply don't preserve because tropical forests often have various acidic soils, high rainfall and also hot humidity conditions that can really limit the preservation of remains such as bones and plant material. One of the first things we've been doing is investigating these environments more closely and trying to produce site sequences that really preserve these remains and allow us to get extra details as to what humans were doing. A second step related to that is we've also started to apply some biochemical techniques. A single site may just represent humans living in an area for a few weeks or a few months. Furthermore animals and plants preserved that site might just represent a single meal. So even if they provide evidence for the exploitation of tropical forest animals such as monkeys or plants such as toxic plants that grow on the forest floor that doesn't necessarily mean that humans are doing that for the whole year or indeed for most of their lives. One approach I've really tried to apply in this context is stabilized-type analysis of tooth enamel. This is applying looking at the biochemical composition of the really hard mineral parts of our teeth that contains information as to what we consume throughout the period of formation. This is helped by the fact that the stabilized-type composition of plants and animals that grow under dense forest canopies is very different to that of plants and animals living and growing in more open conditions. As a result we can use the stabilized-type analysis of human teeth to see how much of these different resources they were consuming and whether they were living there for a long period of time and relying on those environments for their resources. Once we've potentially established that humans are living in environment we're also interested in looking at whether they were modifying them. For this there is an emerging set of very high-tech techniques ranging from paleo-environmental coring of lakes to build up a regional picture of vegetation changes and how humans might be cutting down forests or altering forest structure and more recently is a very excited methodology called LIDAR where lasers are bombarded from an aerial vehicle such as a plane or a drone and these bounce back from the forest structure but also the ground and it allows us to strip away the forest and see what's actually lying beneath and look at earthworks and modifications that humans have made in areas that we usually couldn't normally survey as archaeologists. A review of the growing archaeological work in tropical forests revealed that our species actually entered these environments much earlier than previously considered. In Southeast Asia there are now suggestions that humans were living in rainforest environments 75,000 years ago. In Sri Lanka potentially as early as 45,000 years ago and definitely in other parts of Southeast Asia 45,000 years ago. Similarly even in these montane tropical forest environments of New Guinea which are very different to what we would think of as tropical rainforest being very cold in winter we also have evidence for human occupation 45,000 years ago. There are also now suggestions although these remain debated that our species may have occupied rainforests in Africa as early as 200,000 years ago. In terms of looking at human modifications to tropical forest the growing evidence from environmental records from lake cores looking at modern forest structure and looking for potential past human impacts on that structure as well as evidence from LIDAR and remote sensing methods with laser technology. We've been able to find that significant agricultural and urban societies existed in tropical forests in the past. In some cases this led to a sustainable existence that lasted over a course of millennia. In other cases it appears that this may have led to more degraded landscapes and eventual soil erosion that have left communities more vulnerable to climate change in the future potentially leading to the collapse of social mechanisms. But what is clear is that humans in all cases were very able to adapt to their local environment incorporating even new forms of living such as agriculture coming from outside tropical forests into existing ways of living and forest succession strategies and different forest ecologies. Finding humans in tropical forests at such an early date really contributes to our understanding of our species and its adaptive capabilities when it emerged in Africa and also when it expanded beyond Africa. Tropical forests are just one of a number of extreme environments including high altitude settings, the Arctic Circle and potentially also desert conditions that our species appears to have been able to adapt to in contrast to other hominins such as Neanderthals or homophoresiensis. So as a result finding humans in tropical forests and looking at how they've adapted to those environments potentially has implications for defining how we define our species and how our species is unique in an environmental context relative to other hominins. This has been further aided by observation through stabilized analysis that our species could not only use tropical forest environments but it could also specialize in tropical forest environments. Finally in terms of tropical forest modifications given that these environments are incredibly threatened in today's world and are heading towards major damage across many of the tropical continents it becomes significant to find out that actually humans have been living pursuing agriculture even pursuing urban life ways in tropical forests for millennia. So we have a rich data set not just a data set of humans living there but also how they affected the environment and how the environment responded to them living there that can potentially inform on predictions for future tropical forest damage as well as potential policies and ways we should be using tropical forest landscapes that have often been ignored. So I think we still only brush the surface of the relationship of our species with tropical forest environments and there certainly remains much more work to be done. Much of the Central African rainforest remains almost virtually unexplored by archaeologists and paleo anthropologists and is almost certainly home to the first examples of when our species interacted with these habitats. Furthermore stable isotope analysis remains to be applied not just to our species but also other hominins that potentially lived in these environments things like homo fluosiensis or the Hobbit or Homo erectus that both made it to tropical Southeast Asia are yet to be studied using stable isotope approaches and this could really test whether these hominins were also able to inhabit tropical forest environments or whether they entered different parts of this region or at times when this region was covered in more open grassland rather than tropical forest. In terms of looking at human past histories of human forest shaping and disturbance again this has often been focused on in very regional ways so there has now been a lot of work done in the Amazon but there has been less comparative work to other tropical forests and how different human agricultural strategies and urban settlements have contributed to environmental change and modern forest structure in other parts of the world. Furthermore if we are to use archaeology in a more than anecdotal way in a conservation or policy-making setting it's important to get to a stage where we can have data sets that we can actually model on a global scale so we can begin to compare today's statistics and today's records of how humans are modifying tropical forests to how humans have modified those environments and shape them in the past and so we can understand how the rate of change how the nature of the change has really changed through time and that can help us to inform how we interact with these environments today and how these environments might change in the future with different types of human activity.