I am interested in the research, teaching, and application of passive and active ground to satellite-based remote sensing and geographic information system (GIS) technologies to problems in landscape ecology, physical geography including synecology/biogeography, environmental monitoring, ecological restoration for developing solutions to restoring or maintaining the sustainability of dryland landscapes and their pastoral peoples.
GEOG 309: Special Topics: Pastoralism in Drylands, Undergraduate course.
GEOG 413: Introductory Remote Sensing of the Environment, Undergraduate/Graduate course.
GEOG 435: Biogeography, Undergraduate/Graduate course.
GEOG 493: Independent Study, Undergraduate course.
GEOG 494: Undergraduate Research Experience, Undergraduate course.
GEOG 500: Thesis Research, Graduate course.
GEOG 501: Colloquium in Geography, Graduate course.
GEOG 505: Directed Research, Graduate course.
GEOG 506: Directed Research, Graduate course.
GEOG 513: Advanced Remote Sensing, Graduate course.
GEOG 593: Independent Study, Graduate course.
RLEM 314: Rangeland Management Principles Around the World, Undergraduate course.
RLEM 316: Rangeland Communities and Ecosystems, Undergraduate course.
ESSM 462: Advanced GIS for Natural Resources Management, Undergraduate/Graduate course.
ESSM 652: Advanced GIS: Problems in Spatial Modeling, Graduate Course.
ESSM 692: Graduate Independent Research, Graduate Course.
EVSC 410/710: Introductory Remote Sensing, Undergraduate/Graduate course.
Soil Physics & Conservation Management
Principles of Rangeland Science & Management
University and Department Service
Geography Search Committee Member for Department Head, Fall 2016 – Spring 2017
Graduate Program Committee Member 2016-2017
Special Events Coordinating Committee 2016-2017
Elected Connections/Global Packages Committee Representative to College of Arts & Sciences Committee 2016 - 2019
Department Representative for Spring Graduation Ceremonies 2016
Department Representative for Fall Graduation Ceremonies 2015
Departmental Colloquium Organizer Fall Semester 2015
Stewart McCroskey Fund Committee, (chair) 2015 - 2016
Stewart McCroskey Fund Committee, (member) 2014 - 2015
Stand-In for Dr. Li to the UT Undergraduate Council, 2014
Faculty Meeting Minutes Recorder 2014 - 2015
Diversity Graduate Recruitment 2014 - present
Robert G. Long Award Masters Committee 2014
Technical Fee Committee member, 2014-present
Claxton Space Coordinator 2013 - present
Graduate Publications Committee 2013
Graduate Specialty Examinations Committee 2013
Burchfiel Geography Space Committee 2013
Search Committee member 2008, 2011 for Blackland Research & Extension Center Assistant Professor in Agroecosystems
Search Committee member 2009 Department of Ecosystem Science & Management, Texas A&M University Selection for Integrative Ecosystem Scientist at Associate/Full Professor tenured/tenure track position
Search Committee member 1992 for Dean of Graduate School
Participant/panelist 1991 First and Second African/African-American Summits in Cote d’ Ivoire and Gabon
Grasslands, Rangelands & Pastures Indicator Team 2012-present National Climate Assessment of the US Global Change Program.
Steering Committee of the US National Academies of Sciences, Engineering, & Medicine and Mexico Academy of Science on Sustainability Science in US-Mexico Border Drylands October 2017 - December 2018
Signicant areas of the southern USA periodically experience intense drought that can lead to episodic tree mortality events. Because drought tolerance varies among species and size of trees, such events can alter the structure and function of terrestrial ecosystem in ways that are difficult to detect with local data sets or solely with remote- sensing platforms. We investigated a widespread tree mortality event that resulted from the worst 1-year drought on record for the state of Texas, USA. The drought affected ecoregions spanning mesic to semiarid climate zones and provided a unique opportunity to test hypotheses related to how trees of varying genus and size were affected. The study was based on an extensive set of 599 distributed plots, each 0.16 ha, surveyed in the summer following the drought. In each plot, dead trees larger than 12.7 cm in diameter were counted, sized, and identified to the genus level. Estimates of total mortality were obtained for each of 10 regions using a combination of design-based estimators and calibrated remote sensing using MODIS 1-yr change in normalized difference vegetation index products developed by the U.S. Forest Service. As compared with most of the publicized extreme die-off events, this study documents relatively low rates of mortality occurring over a very large area. However, statewide, regional tree mortality was massive, with an estimated 6.2% of the live trees perishing, nearly nine times greater than normal annual mortality. Dead tree diameters averaged larger than the live trees for most ecoregions, and this trend was most pronounced in the wetter climate zones, suggesting a potential re-ordering of species dominance and downward trend in tree size that was specific to climatic regions. The net effect on carbon storage was estimated to be a redistribution of 24–30 Tg C from the live tree to dead tree carbon pool. The dead tree survey documented drought mortality in more than 29 genera across all regions, and surprisingly, drought resistant and sensitive species fared similarly in some regions. Both angiosperms and gymnosperms were affected. These results highlight that drought-driven mortality alters forest structure differently across climatic regions and genera.