NSF Award
2409468
Global changes are causing significant shifts in ecosystems worldwide by increasing environmental stress. Species that can withstand these changes are likely to thrive, while those less adaptable may decline. However, it is challenging to link strategies of individual species to community-level responses to global changes. This project explores the vertical layers of forests to test the role of competition and tolerance in community assembly. Abiotic stressors including temperature (3-6°C higher in the canopy), dryness, and microclimate variability increase from the forest floor to the canopy, all within just 20-30 meters of height. This project evaluates how differences in life history strategies, such as tolerance to stress, interactions with other species, and the capacity to colonize new habitats, play a role in community assembly and responses to environmental change. Additionally, this project will develop a curriculum module for secondary school students that aims to foster student involvement in science including the development of educational materials about the value of microbial diversity in nature. The project will develop a novel molecular tool and database for characterizing microbial taxa and traits across the life history strategies, which will be made widely accessible to scientists and practitioners. Finally, the project will support early career scientists by providing professional development and mentorship opportunities for a doctoral student, a research technician, and three seasonal field research assistants.<br/><br/>This research will develop a model system – the vertical dimension of forests – to systematically test community assembly and life history tradeoffs of microbial communities across the vertical gradient in a Panamanian tropical rainforest. This will include (1) a multi-omic characterization of the functional and taxonomic diversity of soil communities along the vertical gradient, (2) an assessment of the communities dispersing via air, water, and detritus across the gradient, (3) a reciprocal transplant experiment to test abiotic and biotic controls of community assembly, and (4) a lab-based incubation to specifically evaluate the roles of heat and water stress in shaping community assembly. Finally, the project will (5) synthesize the results using a causal inference modeling approach to explicitly test the role of the competitiveness-to-tolerance tradeoff in shaping community assembly in response to abiotic stress. This project will make significant advances in our understanding of how abiotic stress influences community assembly. Most importantly, this work will test whether a tradeoff between tolerance and competitiveness determines the outcomes of community assembly across a gradient of abiotic stress. Beyond tolerance and competitiveness, the results from this work will provide the first detailed information about trends in dispersal along the vertical gradient and how they vary among different pathways of dispersal. This study will characterize the vertical dimension of microbial diversity in forest soils for the first time, providing insight into this major understudied dimension of global diversity and establishing a model system for testing principles of community assembly.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
