"Like most mathematicians, he takes the hopeful biologist to the edge of the pond, points out that a good swim will help his work, and then pushes him in and leaves him to drown."-charles elton

Aquatic Research Pond, July 2015


About Rachel

I am currently finishing a PhD in Ecology and Evolutionary Biology under the direction of Dr. Lawrence J. Weider at the University of Oklahoma. As concisely as possible, my working thesis involves using theory and experimentation to better understand how population structure influences community properties and stability. I am using Daphnia as a model organism, linking their life-history traits to communities through size-distributions. In other words, I get excited over equations and graphs, while trying to keep myself grounded in real systems.



Research interests

Linking populations and communities

Population ecologists tend to focus on a single species, and what elements (e.g. food abundance, predation) affect growth and reproduction. On the other end of the spectrum, community ecologists focus on how the ecosystem functions as a whole. Individual variation and population dynamics are often overlooked in community and ecosystem ecology. My research strives to unify population and community approaches in order to understand a population within its community. It aims to help predict changes in population demography by understanding mechanisms governing life-history dynamics.

Ecologists commonly use size distribution data to tie individuals and populations to community-level functions. Size-based field analysis has been used in aquatic field studies since the early 1960s when zooplanktonsize-distributions were measured. The linkages between body size, physiology, and their implications in ecology was developed by Kerr (1974) and has since been used in empirical work to connect the individual to the ecosystem. While body size seems to be more informative in these studies than species identity, there is still ongoing discussion about what the relative effects species identity and body size may play in community structure.

Community persistence and stability

Currently organisms are experiencing change at an unprecedented rate. Therefore knowing what traits or functions enhance a community's ability to persist through time, resist environmental change, and be resilient post environmental events are vital to conservation efforts. Genetic variation, species diversity, species connectivity, and other aspects of community properties have been implicated in community persistence and stability. My research is particularly interested in 1) how intraspecific variation may enhance the stability of community networks, 2) the relative importance of different aspects of biodiversity influences a community's ability to persist (re: species evenness) and 3) the role of species diversity vs. abundance on community persistence and stability.

Species evenness

Biodiversity, commonly measured by species richness, is the cornerstone of ecological research. Another metric of biodiversity that may play a role in community function is species evenness. Species evenness measures the proportions of relative species abundance to community abundance. A meta-analysis of aquatic ecosystems has shown little to no correlation between species richness and species evenness, indicating that species evenness is an independent axis of biodiversity. Species evenness may play large roles in community properties such as persistence, resilience, and resistance in the face of environmental change.


Patten, M.A. and R. N. Hartnett. 2014. Residual variance is no cause for alarm. Frontiers in Ecology and the Environment. 12:545-546. pdf