Date of Award
Master of Science
Natural Resource Ecology and Management
Janette R. Thompson
Catherine M. McMullen
The forest herbaceous layer provides important ecosystem services, but land use changes have led to a decline in native herbaceous perennial species in the Midwest, including Iowa. Restoration focused on the herbaceous layer is uncommon, and best practices have not been established. Significant debate has developed over appropriate plant sources for restoration: geographically distant populations of the same species are often genetically distinct, and this phenomenon may affect restoration success. In the first part of this study, I examined genetic variability and phenotypic plasticity of local and nonlocal populations of six herbaceous perennial understory species. I used a common garden study to test for genetic variation in vegetative and reproductive traits and a field study to test for phenotypic plasticity. I detected genetic differences between local and nonlocal populations for about half of the measured traits, and observed that few trait differences in greenhouse trials were also consistently expressed by plants in the field due to phenotypic plasticity. In the second component of this study, I examined the recommendation to practitioners to use local ecotypes in restoration. I surveyed two stakeholder groups, conservation professionals and nursery professionals, to learn if there were differences between the two groups in terms of perception, use, or sale of native and local ecotype plant material. I found that 78% of conservation professionals use native plants for a majority of their restoration projects, while only 9% of nursery professionals sell a majority of native plants. There was also a time lag between demand and supply for these plants: 67% of conservation professionals have been buying native plants for >10 years, while only 25% of nursery professionals have been selling native plants for that long. Although conservation professionals indicated interest in using local ecotype plant material, only 30% of survey respondents and 22% of their organizations have plant sourcing guidelines. Members of both groups reported that they rely on trusted authorities and professional training for information on local ecotypes, representing an opportunity to encourage collaboration and create sources of native plant materials, particularly herbaceous perennial species.
Emily Anne Altrichter
Altrichter, Emily Anne, "Restoration of the forest herbaceous layer: genetic differentiation, phenotypic plasticity, and opportunities for conservation and nursery professionals" (2016). Graduate Theses and Dissertations. 15105.