Relationships of the Invasive Plant, Sisymbrium altissimum L., with the Plants and Butterflies of Craters of the Moon National Monument and Preserve

Kaiser, Sara

Brief Description: Study of the distribution of plants and butterflies at Craters of the Moon National Monument and Preserve (CRMO) examining whether the diversity or abundance of native and non-native plants or the abundance of pierid butterflies were related to S. altissimum distribution or abundance. Full Description: Invasive plant species can disrupt the pre-invasion food web. Sagebrush steppe is a widespread semi-arid ecosystem that has been degraded by changes in land use and is being invaded by exotic plants. Sisymbrium altissimum (Brassicaceae), an abundant invasive mustard species in the western US, is common in sagebrush steppe. Some herbivores, such as pierid butterflies, use native mustards as host plants and may use invasive S. altissimum preferentially. However, the trophic interactions between S. altissimum and native plants and butterflies are not known. We studied the distribution of plants and butterflies at Craters of the Moon National Monument and Preserve (CRMO) and examined whether the diversity or abundance of native and non-native plants or the abundance of pierid butterflies were related to S. altissimum distribution or abundance. We found evidence of lower total native richness at a local scale, and similar trends at a kipuka-wide scale. Native plant cover was also lower where S. altissimum was more abundant. Pierid abundance was higher where S. altissimum was more abundant. Pierids likely use S. altissimum in addition to native mustards as hosts, increasing their abundance, but the relationship between S. altissimum and native plants is still unclear.

Relationships of the Invasive Plant, Sisymbrium altissimum L., with the Plants and Butterflies of Craters of the Moon National Monument and Preserve

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