ARBOLES: A trait-based Understanding of LATAM Forest Biodiversity and Resilience

Latin American forests cover a very large latitudinal and climate gradient extending from the tropics to Southern hemisphere high latitudes. The continent therefore hosts a large variety of forest types including the Amazon - the world's largest tropical forest - as well as the diverse Atlantic forests concentrated along the coast, temperate forests in Chile and Argentina as well as the cold rainforests of Valdivia and the Nothofagus forests of Patagonia. These forests are global epicentres of biological diversity and include several tropical and extra-tropical biodiversity hotspots. For example, the Amazon rainforest is home to ~10% of terrestrial plant and animal species and store a large fraction of global organic carbon. hotspots.

Some of these Latin American forests still cover a large fraction of their original (pre-colombian) extent: the Amazon still covers approximately 5 Million km2, which is 80% of its original area. However, others, such as the Atlantic forest, have nearly disappeared and are now heavily fragmented. Temperate forests have also shrunk, despite efforts to halt further reduction. However, economic development, population rises and the growth in global drivers of environmental change mean that all forests now face strong anthropogenic pressures. Locally stressors generally result from ongoing development, selective logging, the hunting of larger birds and mammals, over-exploitation of key forest resources such as valuable palm fruits, mining, and/or forest conversion for agricultural use. Global environmental drivers stem from the world's warming climate. Yet it is not clear how these local pressures and changing environmental conditions will alter the composition of Latin American forests, and whether there are thresholds between human impacts - such as the lack of dispersers in heavily fragmented forest landscapes or climate conditions exceeding limits of species tolerance - and the community level responses of forest plants.
We aim to investigate this, supporting the development of strategies that can preserve the diversity of these forests and their functioning. We achieve this by investigating the relationships between diversity and functioning of these forests; exploring whether there are thresholds in functioning resulting both from pressures of forest use and changing climate; by experimentally testing responses; and by generalizing predictive capability to large scales. ARBOLES aims to achieve these goals by integrating established forest inventory approaches with cutting-edge functional trait, genomics, experimental and remote sensing approaches.

Our approach involves combining forest plots with plant traits, which will enable us to characterize state and shifts over time in the face of local human disturbance and changing climate and atmospheric composition. We will focus on traits along the following axes: (i) life-history strategies measuring investment in structure (like wood density, leaf mass per area, maximum height), (ii) investment in productive organs (like leaf nutrients), (iii) investment in reproductive organs, (iv) tolerance to water stress and heat stress. The work is being conducted in collaboration with research groups in Argentina, Brazil, Chile and Peru - and will provide a first cross-continent assessment of how humans are influencing Latin American forests.

ARBOLES has clear societal applications. Results of our analyses will demonstrate which plant species groups are most impacted by global environmental change and by local disturbances. Furthermore, they will inform us about which plant attributes (traits) underpin ongoing changes in composition across LATAM forests. Our results will further highlight the relative impacts of different forms of disturbance (e.g. defaunation, logging) thus providing a basis for prioritising policy for conservation. Our experimental work (warming/drying) on key plant species used for restoration will provide a basis for restoration practitioners to select species which are more tolerant to climate change (climate-smart agriculture). Similar work conducted on taxa of important agricultural and forestry values will further yield insights into the sensitivity of these species to climate change. Finally, our remote sensing work will provide new large-scale insights into the resilience of LATAM forests to local and global change that are likely to have important development and conservation implications, providing regional policymakers with understanding of how vulnerable different forest types may be to local and global stressors.

ARBOLES team members span four LATAM countries (Argentina, Brazil, Chile, Peru). The project will enhance scientific capacity within LATAM countries by promoting clear opportunities for early-career scientists to be part a leading scientific team. The reach of the scientific capacity building we propose will be supported by the diverse range of research institutions involved beyond the funded partner countries (including project partner participation from Bolivia, Colombia and Venezuela). ARBOLES will fully supporting science-society links by engaging with government and non-government institutions involved in natural resource management or monitoring, such as the National Institute of Space Research(INPE) who oversee monitoring activities in Brazil, the Forestry Institute (INFOR) in Chile who have been undertaking forest inventories across the country, the Instituto Socioambiental (ISA) who coordinate community-based restoration in Mato Grosso and the Jardin Botánico de Missouri who are a scientific and education NGO based in Oxapampa in Peru. These linkages will ensure that our results have a clear path to policy impact.