My work focuses on the process of adaptive evolution and its role in facilitating population divergence and speciation. I predominately use next-generation sequencing and comparative genomic approaches to investigate how adaptations arise and what their effects are on overall genetic diversity. Among my current projects are an examination of divergence and selection in two species of hybridizing tiger swallowtail butterfly and an investigation of toxin resistance and sequestration in fireflies.
Lowland tropical rainforests are one of the most productive ecosystems on the planet. However, their future as carbon sinks during times of global climate change is uncertain in part due to an incomplete understanding of tropical tree nutrient use. My dissertation project combines theoretical modeling with empirical field measurements and experimentation in the forest at La Selva Biological Station in Costa Rica. I use the perspective of individual trees and species specific traits to examine nutrient limitation in lowland tropical rainforests.
This work has implications for species evolutionary success, forest composition, and ultimately the role of lowland tropical rainforests in the global carbon cycle.
My primary research interests are broadly situated in the fields of conservation biology and biogeography. There are two main goals of my dissertation research stemming from these interests. The first is to determine the factors that limit the distribution of birds along altitudinal gradients. To accomplish this I am conducting bird surveys along two elevational gradients in the western Himalayas that differ in terms of species richness, climate patterns, and habitat types. The second goal is to assess how disturbance from grazing, agriculture, and logging are impacting Himalayan bird communities both on their breeding and wintering grounds. This is possible in light of the close proximity of breeding and wintering grounds by many species that undergo short-distance altitudinal migrations in the Himalayas. A bonus third goal is to rediscover the Himalayan Quail, an extremely rare and secretive bird last seen in 1876 very close to one of my study sites.
With a broad interest in understanding the nexus of human, wildlife and ecosystem health, Christina is using her dissertation to skim the surface of the complex interactions pathogens have with their environments and hosts. She is interested in short-term conservation implications and long-term evolutionary implications of cross-species transmission events associated with land use change. For her dissertation project, Christina is collaborating with some delightful individuals from the Eijkman Institute of Molecular Biology in Jakarta, Indonesia. Through this collaboration, they are examining how heterogeneous landscapes across Indonesia shape vector-borne disease transmission, with a focus on mechanisms for promoting cross-species transmission events. This research has also inspired a broader interest in the theoretical underpinnings of vector-borne disease transmission, which she plans investigate through the lens of various land use change regimes
With a background in architecture, I am interested in the processes and behaviors that generate structure, pattern and spatial organization in biological systems. My current research is focused on the self-assembling structures formed by the army ant Eciton Burchellii, as well as the self-organized temporal and spatial dynamics of the trail networks created by these ants to transport prey items efficiently.
Sam's research is focused on understanding the drivers behind vegetation fire at global and regional scales in order to understand the future impact of burning on ecosystems and the atmosphere. He is especially interested in how changes in land use and land cover, land management practices, fire regimes, and regional climate will affect the Amazon rainforest.
I am interested in mammalian behavioral ecology and conservation, particularly human-wildlife interaction. My research investigates wildlife populations and their interactions with their environment, focusing on how human land use practices affect animal behavior. I am currently studying how cattle grazing influences the behavior of various wild grazers on Kenyan rangelands. This is an important question because forty percent of the earth’s land surface is currently used for grazing domestic animals. These lands are also vitally important for conservation as they can provide a means to preserve open space to sustain wildlife outside of national parks. In some areas, it appears that cattle and wildlife can live side-by-side. However, many issues must be considered and managed properly in order to allow wildlife and livestock to coexist. Therefore, I hope to conduct research that not only furthers ecological theory, but has practical implications for wildlife conservation and management as well.
I am interested how nutrients and light resources may constrain productivity of tropical forests in a world of rising CO2. My work focuses on nitrogen-fixing plants which are the main source of new nitrogen into an ecosystem and how they are limited by light and other nutrients such as phosphorus and molybdenum (a trace metal important in N2-fixation). To further my research goals, I have done field fertilization experiments as well as glass house experiments where I can manipulate CO2 and light levels in Panama.