6100 Main St, MS-170
Houston, TX 77005



Research Overview

Population dynamics are temporal and spatial changes in the state of a population (density and composition). Population dynamics are central to studies of the distribution, abundance, and persistence of individual species, and are the building blocks of ecological processes at the community and ecosystem levels. Population dynamics are also the vehicle of evolutionary change. If nothing in biology makes sense except in light of evolution, one could argue that nothing in ecology or evolution makes sense except in light of population dynamics.

As quantitative population biologists, our lab studies how populations work. On first glance, this task may appear straightforward, as population change is composed of just two ingredients: demography (births and deaths) and dispersal (immigration and emigration). However, the sources of variation in demography and dispersal are daunting. The work in my lab focuses on decomposing variation in individual-level demography and dispersal – including the influences of demographic state (stage, size, sex), intra-specific interactions (competition, mating), inter-specific interactions (mutualism, parasitism, competition), interactions with the abiotic environment (climate drivers), and stochastic forces (environmental and demographic noise) – and evaluating how these processes scale up to influence populations and communities.

Tom doing field work

Our work relies heavily on the development and application of mathematical models, especially structured population models, which allow us to connect individual demography and dispersal to population-level processes. Some of this work is purely theoretical, some of it purely empirical, but the majority lies at the interface of theory and data. I am a firm believer in the value of integrative, theoretical-experimental approaches for connecting patterns we observe in nature to the processes that generate them. I am also excited about the power of statistics for building connections between theory and data.

Because the rules of population dynamics are very general, we can and do conduct work in a variety of biological systems. Research in the lab is intentionally broad, but all of our projects are united by a focus on demography and dispersal, their sources of variability, their effects on population growth and fitness, and by the interplay of theory and data. Most of our empirical work involves plants and / or insects. These taxonomic groups are highly amenable to experimental manipulation and their population dynamics are relevant in a number of applied contexts, including agriculture, ecological restoration, and invasive species management. We conduct experimental studies in the greenhouse, in the laboratory, and in the wild.

You can follow these links to learn more about specific lab projects:

Range expansion and range boundary formation
Plant demography and ecological interactions
Stochastic population dynamics