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Abstract
An ecological classification of natural habitats based on their vegetation, topographic position, soil texture, hydrology, fire frequency, and plant nutrient availability was recently developed by Van Kley et al. (2007) as a management tool for east Texas forests. This classification scheme did not take into account such important components of terrestrial ecosystems as microbes, particularly arbuscular mycorrhizal fungi (AMF). In the current work AMF diversity across different natural east Texas habitat types was studied by a molecular approach: denaturing gradient gel electrophoresis (DGGE) analysis of five hundred and fifty base-pair fragments of the small subunit ribosomal DNA (SSU rDNA) gene from AMF. One hundred and thirty seven DGGE profiles were obtained. AMF communities associated with the host plants were rich in AMF types as indicated by the large number of bands per sample. Multivariate analysis of the one hundred and thirty seven DGGE profiles showed that AMF exhibited host preference and that the AMF community composition was related to habitat. A set of measured environmental variables was found to be correlated with the composition of the AMF community. AMF community composition can be used as an additional factor in ecological classification of natural east Texas habitat types.
