Schwinning Lab

Plant Ecology

Karst Ecohydrology

A road cut exposes how roots grow through the 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.

Dammeyer, H.C., Schwinning, S., Schwartz, B., Moore, G. 2016. Effects of juniper removal and rainfall variation on tree transpiration in a semi-arid karst: Evidence of complex water storage dynamics. Hydrological Processes 30: 4568-4581. pdf

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

Evan Simon presented his research at the 2022 TXSER in Austin entitled "The Relationship Between Elevation and Response of Trees of the Edwards Plateau to Drought." He won the first prize for an Oral Presentation by an Undergraduate Student.

Highlighted publications

A long-awaited Special Feature in the Journal of Ecology has finally been completed. These are our lab's contributions:

Schwinning, S., DeFalco, L.A., Esque, T.C. 2021.What common-garden experiments can tell us about climate responses in plants. Journal of Ecology 110: 986-996 pdf

Custer, N.A., Schwinning, S., Lortie, C.J., Esque, T.C., DeFalco, L.A. 2021. Local climate adaptations in two ubiquitous Mojave Desert shrub species, Ambrosia dumosa and Larrea tridentata. Journal of Ecology 110: 1072-1089. pdf

Other lab news

The following students have received research awards in 2022:

Evan Simons, who conducted research towards an undergraduate honors thesis, was awarded an undergraduate research followship by the College of Science and Engineering. He also won the first prize for the 'Best Undergraduate Oral Presentation' at the TXSER conference (Society for Ecological Restoration, Texas Chapter).

Owen Moorhead won the Ann Miller Gonzalez Graduate Research Grant from the Native Plant Society of Texas (NPSOT) to conduct an experiment in prairie restoration in collaboration with the Native Prairies Association of Texas (NPAT).

Silas Jenkins won the Ann Miller Gonzalez Graduate Research Grant from the Native Plant Society of Texas (NPSOT) to investigate the importance of mycorrhizal fungi for the survival of oak seedlings under drought.

Contact information

Susan Schwinning

601 University Drive

312 Supple Science Bldg

Texas State University

San Marcos, TX 78666, USA

Email: schwinn@txstate.edu

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