Research

Environmental Gradients and Functional Trait Variation

Most species have geographic ranges broad enough such that they have populations of different sizes in a wide variety of environments. Changes in species abundance along environmental gradients have a long history of being quantified in community ecology and it is common for functional ecologists to quantify the change in a mean trait value along an environmental gradient. This gives rise to the expectation that traits interact with the abiotic environment dictating performance and ultimately local abundance. In this project, we integrate information on functional traits, performance along environmental gradients to examine underlying factors driving variation in species abundance.

 

Defining Functional Strategies of Trees

Species phenotypes are the outcome of a combination of multiple functional traits that mediate species responses to the environment and ultimately influence fitness. Often, these traits covary with each other as a result of trade-offs, that constraint trait variation defining trait dimensions. These trait dimensions are useful for classifying and characterizing species into different ecological strategies. However, most of the current knowledge of functional dimensions are focused on leaf traits. We are developing projects interested in characterizing functional dimensions of trees.

Last summer, we started a project at the E.S. George Reserve in Michigan to investigate the relationships between leaf and root economic spectra and their variation along a soil fertility gradient.

Check out the new blog about our work in Michigan

 

Demographic Rates and Plant Traits

While it is broadly recognized that interactions occur at the individual-level resulting in differential patterns of abundance and species distributions, demonstrating the role of these interactions requires the quantification of demographic parameters. I am working on projects that analyze patterns of growth with respect to the abiotic and biotic context integrated with detailed measurements of intra-specific trait variation that will provide a more complete understanding of processes that govern community structure.

 

Photo by Roxy Cruz-de-Hoyos

Intra-specific Trait Variation and Plant Interactions

Studies on trait-based ecology have generally ignored the importance of intra-specific trait differences. However, individuals are far from being redundant and the consideration of within-species trait variation can help us elucidate many important mechanisms underlying species interactions. One of my main areas of interest is to investigate the role of the intra-specific trait variation in plant community assembly.

Some of the questions on intraspecific trait variation have been developed in El Verde Field Station in Luquillo, Puerto Rico where I have been working with seedling communities. In 2013, with my field assistant, Roxy Cruz-de-Hoyos, we published a rapid color guide for the seedling species present at El Yunque.

 

Tree Diversity in the Amazon Forest

The Amazon harbors one of the richest ecosystems on Earth. Such diversity is partially due to plant specialization, associated with the occurrence of a mosaic of forest (i.e. flooded and terra firme forests). In 2009 I established three 1-ha permanent plots in three different forest types in the Colombian Amazon to assess the importance of habitat specialization in driving compositional and phylogenetic variation across the Amazonian forest. These three plots are now part of the Amazon Tree Diversity Network (ATDN). Since then, the team has published great papers that have fostered understanding of the processes that maintain and originate the incredible diversity of these forests.