Conservation Matters November 2014

The Texas Land, Water and Wildlife Connection

IRNR part of TAMU team receiving $1.4 million grant for woodland encroachment research

IRNR part of TAMU team receiving $1.4 million grant for woodland encroachment research

Examining the human factors influencing the encroachment of woodlands into grasslands is the focus of a $1.4 million grant awarded to a team led by Dr. Bradford Wilcox, Texas A&M AgriLife Research ecologist and professor in the Department of Ecosystem Science and Management at Texas A&M University.

“Slowing the Expansion of Woodlands and Increasing the Resilience of Grasslands in the Southern Great Plains” is a three-year project funded by the National Science Foundation.

Joining Wilcox from Texas A&M will be principal investigators Dr. Urs Kreuter, AgriLife Research rangeland scientist also in the Department of Ecosystem Science and Management, and Dr. Andrew Birt, AgriLife Research entomologist in the Texas A&M Knowledge Engineering Lab. Brian Hays, Texas A&M Institute of Renewable Natural Resources associate director, will coordinate the outreach aspect of the project.

Other principal investigators are Dr. Michael Sorice, Virginia Tech University; Dr. Willem van Leeuwen and Dr. Steve Archer, University of Arizona; and Dr. Chris Zou and Dr. Sam Fuhlendorf, Oklahoma State University.

Wilcox explained that the project came about because large areas of the central and western United States have seen woody plants spreading into grasslands used mainly for raising livestock. These grasslands have substantially changed in recent decades and now face a host of contemporary threats, he said.

Previous research implicated change in climate and grazing pressure as factors contributing to this encroachment, Wilcox said. This project will extend that work to include research on the effects of governmental policies and social attitudes toward the use of fire to keep grasslands open, as well as grassland to woodland conversion’s impacts on ecological services and economics.

Researchers will compare three regions with contrasting degrees of woody plant encroachment in Kansas, Oklahoma and Texas to test the hypothesis that changes between grasslands and woodlands are driven by interactions between fire and grazing regimes constrained by policy and culture.

Land cover change fundamentally alters biological diversity, biogeochemical cycles and land surface-atmosphere interactions, thus threatening the sustainability of commercial livestock production systems that are the foundation of rural economies, Wilcox said.

“Maintaining remnant grasslands and restoring degraded grasslands for people who depend on them will require a new paradigm for woody plant encroachment: one that views this phenomenon as a complex social-ecological system within which coupled biophysical, social and cultural processes operate and dynamically interact,” he said.

Wilcox said a variety of ecological and socio-economic facets have been studied independently but not researched as interdependent components at regional scales, as this project will do.

“Guided by our conceptual woody plant encroachment social-ecological framework, we have identified important knowledge gaps in our understanding of this ongoing event and designed a research program to fill those gaps,” he said.

“Our research results, along with existing knowledge about the systems, will be incorporated into a quantitative modeling framework that will enable us to dynamically link human decision-making with ecosystem response.”

To test their hypothesis, Wilcox said the researchers will develop a dynamic, repetitive and evolving agent-based model to analyze factors influencing land managers’ decision-making with respect to using prescribed fire as a management tool.

The model also will forecast changes in regional woody plant cover and ecosystem carbon mass under different scenarios of fire use; project the effects of change between grasslands and woodlands on portfolios of ecosystem services, including forage production, groundwater recharge, stream flow and carbon sequestration; and translate changes in ecosystem services into economic metrics, he said.

Wilcox said when the study is complete, they will be able to provide for the first time a regionwide assessment of woody plants coverage and estimates of how fast the transition from grassland is proceeding — information that will be critical for the formulation of policy and coordinated action.

“We will have a new understanding of how woody plant encroachment affects regional-scale water and carbon budgets; and we will have an improved understanding of how burn associations provide a catalyst for collective action by private land managers to restore and/or maintain grasslands.”

Additionally, he said, the team will provide new modeling approaches that link social processes with biophysical ones, thereby enabling scientists to understand feedbacks and threshold responses and to anticipate behavior.

“This realistic scenario analysis built on such information will give us the ability to educate policymakers as they seek to deal with woody plant encroachment,” Wilcox said.

Read the original AgriLife Today news release for more information.

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