Can tropical Montane forest Acclimate to high temperature? Montane-Acclim

Tropical forests play a critical role in global water, carbon and nutrient cycles, and currently absorb billions of tonnes of carbon, thus reducing rates of climate change. For this reason, computer models that are used to predict future climate change and the impacts of climate on plants and ecosystems, need to be able to represent tropical forest very well. In fact, the response of tropical forests to changes in temperature is one of the greatest uncertainties in climate change prediction. However, currently, scientists do not understand how these forests will respond to increasing temperatures. This is worrying because temperatures are increasing faster today than in the past, forcing forests to respond to unprecedented rates of warming. Critically, the lack of seasonal changes in temperature may mean that trees growing in these regions have a reduced capacity to deal with rapid climate change compared with more temperate and high-latitude species. If this is the case, then global warming may represent a considerable threat to these forests, the amazing amounts of biodiversity that they contain, and their role in reducing current rates of climate change. However, this suggestion is yet to be tested formally.

The lack of understanding is even more worrying for tropical forest growing in mountains, as in these areas temperatures are increasing faster than in the lowlands. For example, scientists studying Andean forest in Colombia and Peru have observed that some tree species native to high elevations are dying out while others are moving to higher elevations. These scientists have suggested that these observations may be explained by the fact that trees are already seeing the impacts of climate change and are not able to withstand current temperatures. However, this explanation remains controversial and has not been tested formally. The major goal of this project is to determine if tropical Andean species can tolerate current temperatures and adjust to withstand the higher temperatures expected for the future. To answer this question, we will plant trees from high elevations in the Colombian Andes in their home environment but also at two lower elevations where temperatures are 5oC and 9oC higher, respectively. Our trees will be all planted in common soils and will have access to plenty of water, eliminating potential differences in water and nutrient access. We will monitor photosynthesis, respiration and growth at the three locations in other to understand how they respond to temperature. Compared to other experiments, our study is unique as it will: i) be the first to investigate the ability of large 3 - 4m tall trees planted in a common soil to respond to long-term (3 year) changes in temperature, ii) investigate a much greater number of species than all other field studies on this subject, and iii) measure a more complete set of key physiological and growth responses than in any other experiment.

The measurements taken will be used to the derive mathematical equations that can represent the response of these tree montane species to elevated temperatures. Furthermore, to predict the response of tropical forest everywhere in the world to higher temperatures, we need data from high and low elevations in as many locations as possible. Scientists around the world are now starting to collect some of these measurements in forests from Costa Rica, Puerto Rico, Panama, Brazil, Peru, Rwanda and Australia. Although, no one of these investigations is as detailed as our study, by teaming up with all these groups we can use their data to test and extrapolate our equations across all tropics globally. We will then introduce these mathematical equations into a computer model to predict future behavior of the tropical forest under warming conditions. The outcome will represent a step change in our ability to accurately predict how this critically important biome will respond to global warming.

Who will benefit from the proposed research and how
Our project is of relevance to the IPCC community & international climate change policy, local stakeholders, conservation bodies,local policy makers, NGO's, educational institutions and the general public.

IPCC, IPBES & international climate change policy Future climate model projections form the basis of Working Group One and reducing uncertainty in climate projections is core to development of the Earth System Model (ESM) used in IPCC reports. This project will provide information on temperature responses of tropical forests, a key uncertainty in current ESM projections. Future projections from our project, with improved representation of thermal tolerance in JULES (the land surface model of the UK ESM) are thus highly relevant to future IPCC reports. IPCC reports influence climate policy, therefore our results indirectly impact on International climate change policy. The Intergovernmental Platform on Biodiversity & Ecosystem Services (IPBES) will also benefit from the results of this project as we will provide key information on the range of sensitivities to high temperatures for Andean tree species which can inform basis for future biodiversity of the region.

Local stakeholders, policymakers and NGO's
The Andean mountains provide key ecosystem services to a large portion of Colombian society living in the highlands such as freshwater for drinking and hydroelectricity production. Therefore, the main stakeholders in this project are the hydroelectricity generators ISAGEN, EPM, ENGESA, URRA & CHIVOR; and EPM, the regional energy and water supplier. Two local regional governmental institutions, CORNARE and CORANTIOQUIA, are responsible for local environmental policy and regulations. Their remit includes forest conservation, environmental licenses and permits, reforestation, improved models of climate change predictions for Colombia, tools to assess risks & threats of climate change to ecosystem services, wood production and biodiversity, and tools to design climate change adaptation and mitigation strategies. Conservation and biodiversity is also within the remit of some local and international NGO's with offices in Colombia. They will benefit from the information we will provide on which forest native species are least and most vulnerable to warming to inform their planning for reforestation, adaptation and mitigation. Additionally, our project will ultimately improve predictions of climate change, which will also inform policy and promote societal adaptation in high altitude tropical regions in the Andes.

Local capacity building
Educational institutions and more specifically the future generation of researches in Colombia will benefit from learning the methodologies used in this project. In order to plan adaptation and mitigation to climate change it is vital first to assess the impacts and threats to ecosystems services and therefore society. Through our project we will build the capacity needed to do this through working with the next generation of scientists (Master to PhD level). They will benefit from learning new methods and techniques to assess climate change impacts on Andean forest in countries like Colombia of low-intermediate income, which is central to the adaptation to climate change agenda.

The general public in Colombia
Overall, climate change will have a direct impact on the population who depend on the drinking water and electricity generated with water from the Andean mountains of Colombia.Since 80% of land has been deforested in the Colombian Andes, conservation of the remaining forest is of paramount importance, e.g. for freshwater and biodiversity. The general public including school children living close to the forest, the local indigenous community, landowners and farmers will benefit from our impact activities by gaining better understanding of the importance of conserving the forest.