Schwinning Lab

Plant Ecology

Yang Tse

Karst Ecohydrology

Tree in rock
A road cut exposes how roots grow through the rock
Roots in rock
Flattened roots of juniper wedged between two rock slabs

Texas State University is located on the edge of the Edwards Plateau, a limestone karst. Karst regions are characterized by thin, rocky soils and outcrops. Over millennia, flowing water erodes the rock below and creates gaps and cavities that enhance water storage capacity, but also allow storm waters to rapidly flow through to deep aquifers.

Not much is known about the rooting habits of woody plants in karst. A high degree of endemism in karst areas suggest that plants require special adaptations for living in karst. Trees typically take up both soil- and rock-stored water, but in what proportions is not well known and may vary greatly among species and across space and time.

In collaboration with Dr. Jennifer Jensen and Dr. Benjamin Schwartz of Texas State University, San Marcos as well as Dr. James Heilman of Texas A&M University, among others,our lab investigates how the rocky substrate of karst regions affects the responses of woody vegetation to precipitation in general and drought in particular.


Tokumoto, I., Heilman, J.L, Schwinning, S., McInnes, K.J., Litvak, M.E., Morgan, C.L., Kamps, R.H. 2014. Small-scale variability in water storage and plant available water in shallow, rocky soils. Plant and Soil,385:193-204 pdf

Schwartz, B.F., Schwinning, S., Gerard, B.M., Kukowski, K.R., Stinson, C.L., Dammeyer, H.C. 2013. Using hydrochemical and ecohydrologic responses to understand epikarst process in semi-arid systems, Edwards Plateau, Texas, USA. Acta Carsiologica 42: 316-325. pdf

Kukowski, K., Schwinning, S., Schwartz, B. 2013. Hydraulic responses to extreme drought conditions in three co-dominant tree species in shallow soil over bedrock, Oecologia 171:819-830. pdf




Lab News

Recent student presentations

Beth Crouchet and Nathan Custer presented on their research at the 2015 International Research Conference for Graduate Students at Texas State University, November 17 - 18, 2015:

Site factors influencing tree mortality during drought in Texas. Beth Crouchet, Susan Schwinning, Jennifer Jensen, Benjamin Schwartz.

Determining seed transfer zones for Mojave Desert shrubs. Nathan A. Custer, Susan Schwinning, Lesley A. DeFalco, and Todd C. Esque.

Highlighted publications

Scott Havill's paper on "Fire effects on invasive and native warm-season grass species in a North American grassland at a time of extreme drought" was highlighted in the October 2015 issue of Applied Vegetation Science (link).

Other lab news

The following students received awards and recognitions in the academic year 2015/16:

Beth Crouchet and Nate Custer received the Biology Department's "Certificate of Excellence"

Beth Crouchet was inducted into the National Honor Society of Phi Kappa Phi

Beth Crouchet received the the Graduate College Scholarship - Science & Engineering and the Lamar and Marilynn Johanson Graduate Endowment Award.

Wesley Collins received a Freeman Center Scholarship.

The lab was awarded two federal grants in 2015:

NSF proposal : DEB-1557176: "Collaborative Research: Hydrological tipping points and desertification of semi-arid woodlands".

The DOD Legacy Award HQ0034-16-2-0006: "Characterizing Mojave Desert shrub ecotypes to establish seed transfer zones for military range restoration".

Podcast interview

In September 2013, Susan was interviewed by Alan Knapp on a paper published in Functional Ecology. Listen to the podcast here.

Contact information
Susan Schwinning
601 University Drive
312 Supple Science Bldg
Texas State University
San Marcos, TX 78666, USA
Phone: (512) 245-3753
Fax: (512) 245-8713

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Biology Department
Texas State University

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Comments on the contents of this site should be directed to Susan Schwinning