Nathan Swenson

Functional perspectives on temperate and tropical forest structure and dynamics: from traits to transcriptomes

Abstract
A significant portion of our planet's biodiversity is held within temperate, subtropical and tropical forests. This biodiversity plays a key role in regulating Earth's climate while providing crucial ecosystem services for our exploding human population. Despite this importance, the processes that produce and maintain levels of biodiversity within and across forested ecosystems remain poorly understood. This lack of understanding not only applies to diverse tropical forests, but also less diverse subtropical and temperate forests. Further, the insights we have about biodiversity in forested ecosystems primarily concern the distribution and dynamics of species diversity. We know far less about the processes regulating the functional diversity in forests that is likely to be more closely related to ecosystem function and services and more informative regarding the drivers of forest structure and dynamics. Indeed, ecologists are increasingly demonstrating that functional diversity is often a superior predictor of ecosystem function and community dynamics than species diversity. Despite these successes, there are existing limitations to this line of research, which depends on the measurement of a handful of easily measured phenotypic traits. Specifically, the traits measured are only proxies of the physiological processes of interest, are weakly or not at all related to demographic rates, and do not include information regarding potentially important known and unknown axes of function (i.e., functional dark matter). An increasingly feasible way to overcome these limitations is through the generation and interrogation of transcriptomic information. Transcriptomes can now be estimated quickly and relatively cheaply for non-model organisms and they provide a snapshot of the aspects of the genome that are being transcribed (i.e., the functional genome). Swenson argues that integrating a large amount of detailed information, such as that provided by transcriptomes, into existing functional trait-based approaches in ecology could help overcome many previous limitations. He will present this argument and evidence from his research group that indicates forest ecology is on the verge of being rapidly transformed via transcriptomic information where long-standing unanswered questions can be addressed in unprecedented detail.

About the Speaker
Nathan Swenson is an associate professor of biology at the University of Maryland. He is a tropical plant field biologist by training with a research focus on using phylogenetic and functional information to understand the distribution and dynamics of biodiversity through space and time. He received his Ph.D. in ecology and evolutionary biology in 2008 from the University of Arizona and was a National Science Foundation postdoctoral fellow in bioinformatics with the Center for Tropical Forest Science at the Arnold Arboretum, Harvard University.  In recognition of his work integrating phylogenetic and functional trait information across scales, he has been named a Fellow of the John Simon Guggenheim Memorial Foundation. He also received a 2011 Jasper Loftus-Hills Young Investigator’s Award from the American Society of Naturalists and the 2012 Ebbe Nielsen Prize from the Global Biodiversity Information Facility. Since he began his Ph.D. in 2004, Swenson has published over 100 peer-reviewed journal articles and book chapters and one book, and he has received nine research grants from the National Science Foundation funding his work on topics ranging from ecosystem carbon flux to gene expression.