Variation of Functional Traits Across Space and Time: Assessing the Roles of Succession and Temperature on Plant and Microbial Functional Traits to Understand Biodiversity Gradients

Traditionally, the study of biodiversity has focused on quantifying patterns of species diversity, or species richness, by simply counting the number of species across environmental gradients. This approach has been fundamental to ecological investigations and thinking with regards to identifying patterns of biodiversity. Although species diversity is the most commonly used dimension of biodiversity, species diversity alone does not provide a mechanistic understanding of biodiversity gradients. By also quantifying the genetic and phylogenetic diversity of a population, community or ecosystem, ecologists can become more informed on the relationships organisms have with one another, as well as their potential to adapt to changes in their environment. While each of these approaches provides methods for characterizing biodiversity, they do not offer direct insight into what species do, how they function, or how they will respond to changes in their environment. Functional, or trait-based ecology, provides an informative alternative to species-centric approaches that seeks to understand patterns of biodiversity in terms of functional traits. Functional traits capture fundamental tradeoffs in life history strategies that can be used to determine species ecological roles and can be used to scale from organisms to ecosystems to ask broad ecological questions. The overarching goal of my dissertation is to add additional links to trait-based ecology by identifying potential sources of trait variation across different spatial and temporal gradients between varying levels of biological organization. By assessing variation across spatial-temporal scales, I tested two prominent assumptions of trait-based ecology. First, I tested the trait-environment assumption wherein traits affect ecosystem processes. Therefore, there should be a predictable relationship between traits, their environment, and ecosystem function across large ecological gradients and between broad taxonomic group