Date of Award:

2017

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Plants, Soils, and Climate

Advisor/Chair:

Janis L. Boettinger

Abstract

The Uinta Basin hookless cactus (Sclerocactus wetlandicus) is a threatened species native to Eastern Utah. The cactus is found in a landscape highly disturbed by non-renewable energy production. To understand the environmental conditions that support natural growth of this cactus, we asked whether plant communities differed in the undisturbed areas where the cactus is and is not found. We then compared undisturbed communities to those found on disturbed areas such as reclaimed well pads. Plant community characterization was accomplished with the line-point intercept method, and data were analyzed using Non-Metric Multidimensional Scaling. There was no significant difference in occupied and unoccupied undisturbed plant communities; S. wetlandicus associates with the common vegetation found in the study area. In contract, plant communities on the well pads were significantly different from those present in undisturbed locations. The disturbed areas were dominated by non-native weedy species and bare soil, thus differing from undisturbed habitats that contained higher relative vegetation cover and a mix of species from all functional groups both native and non-native.

To help restore this threatened cactus in disturbed habitats as well as prevent future extinction, we developed and tested a protocol for cactus seed germination in the greenhouse and successfully produced seedlings with a ~75% germination rate. Additionally, an important factor contributing to the successful growth of this threatened cactus is the presence of arbuscular mycorrhizal fungi (AMF). By extracting the DNA from root samples of wild cacti we were able to identify the presence of AMF from the families Glomeraceae and Claroideoglomeraceae representing three genera: Rhizophagus, Glomus, and Claroideoglomus. Sequences closest to Rhizophagus irregularis were identified from multiple root samples. Cactus seedlings may be inoculated with the fungi to promote their growth and ultimately their survival in the wild. Our study indicates that because S. wetlandicus is part of the common plant community of the study area and the well pads are vastly different from the common plant community, disturbed areas should be reclaimed in a way that better resembles undisturbed habitats to increase the likelihood that the newly planted cacti can thrive.

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