Katie SchneiderAdvised by Dr. Bill Fagan, Biology Professor
Ph.D. Graduate, '09, Behavior Ecology Evolution Systematics
- Bachelor of Science in Biology, 2002 American University
- Master of Science in Biology, 2003 American University
- Master's Thesis: The Biogeography of the Subterranean Invertebrate Fauna of West Virginia (advisor: Dr. David Culver)
- Dissertation: How the availability of nutrients and energy influence the biodiversity of cave ecosystems (May 2009)
Once a pre-medical student, Katie Schneider now spends her time at the bottom of caves chasing critters. The transition occurred in her junior year in college, when she took a biogeography class that focused on spatial patterns of biodiversity. Katie was intrigued and immediately volunteered to work as a research assistant for her biogeography professor who later became her MS advisor. Katie was motivated by all that she was learning from her advisor, but it wasn't until she went on her first caving adventure that she was convinced about what she wanted to study...
The Ins and Outs of Cave Biology
Katie hopes to use the results of her research on cave characteristics and communities to help guide conservation managers on which sites to protect.
Animals in caves are adapted to subterreanean life, and have very interesting characteristics: they are blind, with slow growth rates, long appendages for feeling their way around in the dark, and are often without pigment. In addition cave species are very vulnerable to extinction because many of them are "endemic species" that are only found in one or two sites. In fact roughly 95% of U.S. cave species are deemed vulnerable or imperiled. Katie's research will help protect some of these subterranean species.
Katie is interested in how biotic and abiotic factors influence the biodiversity of cave ecosystems, and how resource quality may drive some of the observed morphological and life-history adaptations of cave-obligate species. To do this she has worked on three projects that comprise her dissertation: An analysis of the chemical composition of cave arthropods, a two year long ecosystem-level resource manipulation experiment, and a study of spatial biodiversity patterns of cave animals. This research has many implications, particularly providing a basis for conservation management in terms of identifying factors that influence the community composition, dynamics, and distribution of these unique and rare species, which may help to guide conservation-based decisions.
The first part of Katie's work is looking at how the availability of nutrients influences cave adaptation. In caves there is no primary production because there is no sunlight to fuel photosynthesis by plants, so the only source of nutrients comes from the surface such as detritus falling into the cave. Thus the food resources in caves are often of low quality compared to resources on the surface. One way that Katie is investigating the influence of poor nutrient quality is by looking at the phosphorus content of cave millipedes. It is well known that cave species have slow growth rates, but it is unknown why exactly that is. Katie's research suggests that the low phosphorus availability in detritus may drive the slow growth rate of cave animals. Phosphorus, which in invertebrates is found primarily in ribosomal RNA, is a main factor in determining growth rate. To test her hypothesis, Katie is comparing the biochemistry (e.g. P, RNA, and RNA/DNA ratio) of an obligate cave-dwelling millipede to a transient millipede of the same genus.
Manipulating Cave Resources
The next question that Katie asked was how the type of food influences cave community structure and dynamics over time. To evaluate this she removed all of the organic matter from twelve vertical caves to characterize what resources were available for the cave species. This was a challenging undertaking, which resulted in the removal of 1.5 tons of matter comprised primarily of leaf litter and some dead animals. Katie then secured the caves with a box system that prevented any new detritus from falling into the cave, and stocked each cave with either 1-2 bags of leaves or 1-2 dead rats. Every month for 2 years, she rappelled into each cave and monitored which and how many invertebrates had moved to and were using these resources. From this Katie was able to look at succession on resources and determine how food resources drive the cave community.
Biogeography and Caves
The final aspect of Katie's research is trying to figure out why one cave may have many obligate species while another may only have a few. To do this she continued work from her master's thesis where she collected and counted the obligate cave species in over 50 caves. She has repeatedly sampled these caves for two years following completion of her masters to incorporate a certain level of confidence for what she has detected into her analyses. Overall, Katie is looking at how biotic (e.g. species co-occurrence) and abiotic factors (e.g. proximity between caves and other cave characteristics) influence spatial patterns of cave biodiversity.
Going for the Best of the Best
Katie was attracted to study at the University of Maryland based on the excellent faculty and the proximity to other intellectual resources. She really enjoys working in Dr. Fagan's lab because of the great diversity of research projects and many areas of expertise represented within the lab. Though the "Faganites" work in diverse systems all over the world, they are all united in their interest of theoretical and spatial analyses of biodiversity. Since graduating from UM, Katie has been designing curriculum for the Cary Institute of Ecosystem Studies as a Education Curriculum Specialist.