Pictures of my field research- plant patterns in forests and deserts.

Erika Mudrak in front of Larrea tridentata

Erika Mudrak

Postdoctoral Researcher
Iowa State University
Twitter Logo@ErikaMudrak

Ecology, Evolution and
Organismal Biology

Curriculum vitae

I recently joined the staff at
The Cornell Statistical Consulting Unit

See my new homepage at


  • Ph.D. Botany, University of Wisconsin -Madison 2010
  • M.S. Biometry, University of Wisconsin - Madison 2009
  • B.S. Ecology and Evolutionary Biology, University of Rochester 2003
  • B.S. Mathematics, University of Rochester 2003

Research Interests

I am interested in community ecology, macroecology, landscape ecology, and mathematical applications in ecology and evolution.My research involves the development of novel analysis approaches with the use of high resolution community and spatial data sets to answer questions about the dynamics of plant communities when faced with pressures of anthropogenic changes such as habitat fragmentation, the spread of invasive species, and fluctuating deer populations.

Current Research

My post-doctoral research, working with Kirk Moloney, centers on spatial modeling of the annual/shrub systems in the Mojave and Sonoran deserts. Traditionally, annual plants were patchily distributed, were restricted to nutrient rich areas under desert shrubs, and avoided open areas between shrubs. Non-native annuals are able to spread into the areas between the shrubs, filling this area with plant biomass, increasing the fuel load in the matrix, which has historically produced a natural firebreak. Our research, in collaboration with the laboratory of Claus Holzapfel at Rutgers University, aims to understand how fire affects fertility islands and how fire, soil disturbance, and changes in rainfall affect populations of native and exotic annual species.

Doctoral Research

The decline of biodiversity through habitat loss and exotic invasions as a result of human activity is a global phenomenon. My dissertation research explored several aspects of how regional species invasions and declines recently observed in Wisconsin upland forests understories relate to multi-scale spatial distributions of individual species and uses local and regional abundance and site occupancy to test theories of predictability of metacommunity species dynamics. I conducted this work under the guidance of Don Waller at the University of Wisconsin - Madison, working with historical and contemporary data from the Wisconsin Plant Ecology Laboratory.

I conducted a fine scale, spatially explicit study of the nature and strength of species-environment linkages and spatial patterns in populations of spring ephemeral and early summer herbs in a maple-basswood forest in southern Wisconsin. Species declining in abundance tended to be more consistently clustered at smaller scales and highly influenced by soil nutrient variables, while increasing persistent species were less consistent among populations both in environmental dependencies and spatial structure. Response to early spring microenvironments varies greatly by species, giving evidence of micro-scale spatial niche partitioning.

I revisited a technique to visualize the variation of species abundance over sites and expand upon it by quantifying these patterns. Frequency data for 89 species across 62 sites best fit a beta-binomial distribution, as predicted by theory regarding spatially aggregated populations at smaller scales. A spatial Heterogeneity Index calculated directly from the beta-binomial parameters for each species was highly correlated with Morisita's empirical index of dispersion, and may allow us to describe patterns in variation in abundance from several different types of data.

I expanded upon nested subset theory to include frequency data, and show that this framework has some power to predict local changes in incidence and abundance. Models based simply on matrices of species incidence and frequency across sites serve to provide predictions of regional dynamics even in the absence of more detailed information on species traits or site characteristics.

I also began to explore ways to use join-count statistics to quantify spatial distribution of species sampled with a bent-transect of contiguous quadrats. These spatially explicit data replicated over dozens of sites can provide us with an excellent opportunity to assess how local species patterns vary over the larger region.

Figures from data analysis- maps and matrices.

Research Experience

University of Virginia, Biology Department, Charlottesville, Virginia.
Laboratory and Research Technician: Worked with Dr. Deborah Roach to maintain field and greenhouse experiments involving over 25,000 aging plants, coordinating field data collection, processing samples in the laboratory and managing large data sets using Excel. Compiled four years of project data into GIS. Supervised undergraduates. June 2004-June 2005

Smithsonian Environmental Research Center, Edgewater, Maryland.
Forestry Studies Intern: Designed and managed project under mentor Dr. Geoffrey Parker. Studied effect of sunlight on leaf qualities and the possibility of individual leaves as light environment indicators. Assisted with lab projects and general lab maintenance. Fall 2003

Cedar Creek Natural History Area, Bethel, Minnesota.
LTER Project Intern: Assisted with biomass data collection and processing for projects of Dr. David Tilman. Organized data access methods, archival data and metadata, updated research and education web pages. Assisted with large experiment initial setup, cared for small farm animals. Summer 2003

Blandy Experimental Farm, Boyce, Virginia.
NSF REU Recipient: Designed, proposed, and implemented original research protocols under mentor Michael J. Wise from Duke University on evolution of tolerance in Solanum carolinense. Summarized findings in a written report and verbal presentation. Participated in weekly seminars and discussion groups. Summer 2002

Rocky Mountain Biological Lab, Gothic, Colorado.
NSF REU Recipient: Designed, proposed, implemented research protocols under mentor Neo Martinez, Ph.D. on variance of food web composition over space. Wrote a research paper and orally presented findings. Participated in weekly seminars and discussion groups. Summer 2001

Teaching Experience

Conservation Biology, Iowa State University, Guest Lecture and Laboratory Activity Development
Measuring and Describing Ecological Communities. Spring 2012, 2013
Teaching Assistant for General Ecology (Botany 460), University of Wisconsin - Madison. Fall 2009
Teaching Assistant for Intro to Botany (Botany 130), University of Wisconsin - Madison. Spring 2006
Teaching Assistant for Calculus III (Math 143), University of Rochester. Fall 2001


Please see my Mentoring Philosophy and my Mentoring Compact
Mentor for Biology 490 Independent Research. Iowa State University. 2011-2013
Cara Grula, Competitive Abilities of Native and Invasive Species in the Mojave Desert
Mentor for Biology 152 guided research. University of Wisconsin- Madison. Spring 2010
Lydia Weyenberg, The relationship of abundances of six vascular plants
   in Wisconsin's Observatory woods to soil texture.
Courtney Ehlers, Soil Texture in Observatory Woods, Dane County, Wisconsin
   and its Effect on Tree Species Distribution.

Education Training

Research Mentor Training Seminar, Center for the Integration of Research, Teaching and Learning. Fall 2012
Preparing Future Faculty, professional development course, Iowa State University. Fall 2011
Graduate Teaching and Learning Circle on Teaching Strategies,
  Center for Excellence in Learning and Teaching Iowa State University. Fall 2011
Workshop on Teaching Individual/Agent Based Modeling, Humboldt State University. June 2011
Teaching Statistics in the Classroom, University of Wisconsin Delta Course. Spring 2008