Collaborative Research: BEE: Impacts of abiotic environment, pathogen resistance and Pre-Columbian human management on Neotropical canopy palm abundances

In tropical rainforests, local abundances of closely related tree species can vary by several orders of magnitude, providing a compelling context in which to revisit a core theme in ecology: why is it that some species are extremely common, while others are rare? This project seeks to answer this question in South American canopy palm trees, a diverse group that includes several geographically widespread species that vary in degree of usefulness to humans and in patterns of abundance.

The research seeks to quantify the relative and combined influences of ecological, evolutionary, and anthropogenic processes on palm abundances. The research is expected to advance scientific knowledge by integrating perspectives from separate disciplines to achieve a more synthetic understanding of how human, ecological, and evolutionary impacts interact to shape biotic systems.

The project has important societal and economic implications because palms provide food, income, and material for basic needs for millions of humans around the globe. Educational films and teaching modules produced during the project are expected to be used by thousands of high school and college students in the United States. Graduate and undergraduate students, post-doctoral fellows, and high school teachers will receive training.

The research employs a multi-scale sampling design to link local ecological and microevolutionary processes to landscape patterns of abundance to test two major hypotheses: 1) that effective defenses via resistance genes (R genes) give common species the ability to escape negative density dependence, and 2) that human management over the past several millennia has promoted the abundances of useful species. This is achieved by combining contemporary genomic analysis and aerial imaging and machine learning capable of identifying and mapping individual canopy trees over vast areas.

Regular censuses provide information on survival of adults and seedlings of focal species in relation to local abundances, and a nursery experiment will further explore relationships between R gene diversity and seedling survival. The project also tests potential impacts of Pre-Columbian humans on contemporary tree populations using paleo-ecological sampling of soil cores, including charcoal and phytolith sampling, while accounting for abiotic environment.

This approach is expected to shed light on the relative and combined impacts of negative density dependence, abiotic environment, and Pre-Columbian human management, all thought to influence abundance in some way but typically treated in isolation.

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.