Theses and Dissertations - UTB/UTPA

Date of Award


Document Type


Degree Name

Master of Science (MS)



First Advisor

Dr. Anita L. Davelos Baines

Second Advisor

Dr. Kristine L. Lowe

Third Advisor

Dr. Jonathan H. Lieman


The association between soil microbes and plants can influence plant growth and survival as well as alter soil microbial community dynamics. The purpose of this study was to determine how the length of this interaction between plants and bacteria affects the bacterial soil community structure. Soil microbial communities associated with plant communities at different successional stages at the Santa Ana National Wildlife Refuge were investigated. The study sites included three revegetated sites (4 months, 21 months, and 221 months since revegetation) and a control site (native brush, never revegetated). Five soil samples were randomly collected at each site. Soil microbial communities at each site were characterized for density, nutrient utilization, and genetic profiles. There was no significant difference in density among the revegetated sites. Microbial communities associated with plant communities at earlier successional stages used significantly more nutrients and had higher activities than communities at later stages. Amplified Ribosomal DNA-Restriction Analysis (ARDRA) profiled the bacterial community to determine genetic differences in community structure within and among the sites. Restriction analysis using five restriction enzymes revealed more variation within and among bacterial communities associated with plant communities at earlier successional stages than at later stages. Soil microbial communities associated with younger revegetated sites were still in flux as they were undergoing succession and had not yet achieved a climax community.


Copyright 2009 Rowena A. G. Hamlet. All Rights Reserved.

Granting Institution

University of Texas-Pan American

Included in

Microbiology Commons