This project will examine the long-term resilience of Colombian forest ecosystems to environmental and climatic changes and improve understanding of the future implications of forest degradation for Colombian society. We focus on forests that are not pristine in that they are used by local communities and are affected by logging and fire. This fills a research gap in understanding how forests, which may be regarded as biologically 'degraded', have undergone changes in biodiversity, in ecosystem services, and in how they participate in local and global cycles of carbon and energy. The project will achieve this by building a network of permanent ecological monitoring plots across gradients of forest environment and degradation to allow evaluation of biodiversity and measurement of processes such as current and historical effects of fire, and carbon storage and changing climate.This data will be integrated with socio-cultural research, focusing on existing cultures of biodiversity conservation. This understanding is essential if the scientific evidence is to be integrated into long-term management plans and policy, as forest degradation in Colombia is strongly associated with changes to the fabric of social life, including the effects of sustained conflict. Participatory research and interviews will also allow the views and perceptions of key stakeholders, especially local communities, to influence our research priorities and outputs from the beginning. This transdisciplinary work is critical to the implementation of international frameworks for biodiversity conservation aimed at reversing the effects of forest degradation. As Colombia emerges from decades of conflict, substantial changes are already occurring in land use, for example in the cultivation of areas that were previously inaccessible due to security issues. Our results will be scalable beyond the focus of Boyaca and Cundinamarca to the Colombian national scale and across the tropics. Tropical forest degradation affects an estimated 500 million ha globally and is an increasingly important driver in the global carbon cycle. However, in Colombia there is little information about change and recovery from degradation; over what time-scales changes occur; what are the major socio-environmental drivers of change; and to which baseline should forests be restored. Due to this high uncertainty, degradation is poorly quantified by climate policy such as Reduced Emissions from Deforestation and Degradation (REDD+) with the result that global CO2 emissions-cuts scenarios may not be sufficiently ambitious and local projects may not benefit from carbon payment schemes. We propose an innovative transdisciplinary methodology that will bring local knowledge, livelihood strategies and priorities into dialogue with multiple biophysical data sources, in order to evaluate change. We will supplement our existing plot data with new field, socio-environmental, and long-term ecological data to create a unique long-term network of degraded forest plots across Boyaca and Cundinamarca, covering variation in types and degrees of degradation (e.g. logged, logged+burned). We will, further, use these data with remote sensing approaches to evaluate the spatiotemporal variation in forests and assess drivers of change across the region to inform policy, conservation, and management. The project will provide critical information to improve climate and vegetation models that can help to assess whether forests and forest associated agriculture (e.g., coffee, cacao) will be resilient in the face of future climatic changes. This information will be used to inform policy recommendations and transformation pathways co-designed with a suite of stakeholders. In summary, this project can transform understanding of the controls on forest biodiversity and ecosystem service, determine ecosystem resilience to climate and disturbance, and support socio-environmental planning for sustainable resource use.

Understanding the human journey of global colonisation is the history of modern humanity and the development of the diverse characteristics of peoples and cultures around the world. This five-year interdisciplinary project will investigate the peopling of South America, the last continental terra incognita (other than Antarctica) to be colonised by humans, constituting a virtually unprecedented migration of modern humans across richly diverse, empty landscapes during the Late Pleistocene-Early Holocene transition. Situated at the geographical gateway to the continent, the project will investigate one of the most momentous demographic dispersals of our species into the diverse environments of north-western South America, encompassing coasts, savannahs and lowland, Sub Andean and Andean tropical forests. This process took place amidst one of the most significant climatic, environmental, and subsistence regime shifts in human history, which contributed to the extinction of megafauna, plant domestication, and today’s remarkable diversity of indigenous South American groups. Despite its geographical importance and a wealth of archaeological and palaeoecological data across its diverse environments, north-western South America has only been given cursory consideration to understand processes of human dispersion. This project will redress this imbalance by applying an innovative interdisciplinary approach that integrates state-of-art archaeology, archaeobotany, zooarchaeology, palaeoclimatology, palaeoecology, ancient environmental DNA and isotope studies. The results will provide a global comparative perspective to the study of Late Pleistocene human colonisations, hunter-gatherer adaptations, the demise of megafauna and the beginning of plant cultivation and domestication. The results of the project have broader implications not only for archaeology but also for geography, palaeoclimate, palaeoecology, and molecular biology.

Tropical forests are biodiversity hotspots and important biological conservation regions. They deliver key ecosystem services such as carbon sequestration and storage, and water for electricity generation via hydropower (a large source of electricity in many tropical countries) and freshwater provision, serving the needs of millions of people and fast-growing populations in these regions. However, tropical regions have experienced the largest recent increases in heat extremes over the globe, with ongoing warming predicted to exceed the bounds of historic climate variability in the next two decades. This climate change has potentially large but poorly understood consequences for tropical forests. Recent findings suggest that these critical forests appear at substantial risk, in terms of their vulnerability and exposure to warming and its extremes. For example, extreme temperatures in lowland forest reduces tree growth and carbon storage. Furthermore, in the tropical Andes, recent warming has been associated with increased mortality of species in the warm extreme of their thermal ranges, triggering a compositional change towards warm-adapted species across all elevations. The mechanisms underpinning reduced tree growth and species compositional changes remain largely unknown. To predict species composition changes and their implications for forest function and ecosystem services, a mechanistically-informed understanding of the physiological strategies employed by thermally resilient and susceptible species is needed. At our unique warming experiments along elevation gradients in the tropics in the Colombian Andes and in Rwanda in the Albertine Ridge we obtain a range of responses to the warming treatment: some species have died, some have shown reduced growth, while others have increased their growth. Importantly, and contrary to some expectations, plant physiological responses to average site temperatures cannot predict growth patterns. Rather, preliminary evidence suggests that tree growth and survival in the North Andean region and in our experiments in Colombia and Rwanda, is related to species abilities to deal with heat stress. Multiple mechanisms may be involved in determining the ability of species to cope with heat stress, but their relative roles in different settings is unknown. In Rwanda, preliminary data suggest that the most successful species thermoregulate, cooling their leaves via high rates of evapotranspiration to cope with extreme temperature, while species that have shown reduced growth with warming reach very high leaf temperatures (ie they cannot thermoregulate). In contrast, in Colombia, the most successful species are those that emit isoprene to ameliorate heat stress suggesting enhanced thermotolerance may be a key mechanism. Overall, our results demonstrate an urgent need to understand how different tropical tree species cope with extreme rather than average temperatures. Using our experiments in Colombia and Rwanda, this project will deliver new mechanistic understanding of heat stress physiology for tropical forests and possible links to plant growth responses to warming which will inform how we understand and predict composition changes along elevation and climate gradients. We will use a holistic combination of measurements not done before in any ecosystem- thermoregulation, thermal tolerance thresholds, in situ isoprene emissions, and their thermal plasticity- to evaluate tree heat stress strategies. We will combine our experimental data with mechanistic modelling to generalise our results to other ecosystems and with data from Andean trees to determine the extent to which the new understanding of species-level heat stress strategies can explain compositional changes in Andean forest tree species. Our project will support better prediction of future biodiversity shifts and forest function, tropical forest restoration and conservation.