Department of Integrative Biology
Graduate Thesis Defense

Alissa Iverson

Master’s Degree Candidate
Dr. Christina Alba, Denver Botanic Gardens
CU Denver Department of Integrative Biology

When: April 13, 2023 at 4:00pm
Where: Denver Botanic Gardens
Classroom 2 in the Freyer-Newman Center

Also via Zoom; Please email Jacki Craig (jacki.craig@ucdenver.edu)
for the Zoom Link
 

Evaluating potential for plant community and functional change in an urban canal undergoing hydrologic disturbance from Green Stormwater Infrastructure

Soil seed banks, or the natural storage of seeds in the soil, in part determine how plant communities respond to disturbance and, by extension, shape post-disturbance ecological function. Our understanding of urban seed banks, especially in irrigation canals, is severely limited. Irrigation canals are common in semi-arid landscapes and have been shown to fulfill ecological functions similar to urban streams, yet are not often considered as an important habitat. A section of an urban canal in Denver, Colorado, is being repurposed to serve as green stormwater infrastructure, the functioning of which depends on the plant community composition. The response of the plant community to the increased flooding imposed by this change will depend on the composition of both the standing vegetation and the propagules in the soil. To gauge the resilience of this system and assess its capacity to respond to disturbance from increased flooding, I examine the community composition in both the aboveground and belowground plant communities. To uncover the species composition of the seed bank, seeds from canal soil samples were germinated in a greenhouse and emerging seedlings were identified. By uncovering what species have seeds in the soil, comparing the dissimilarity of aboveground and belowground species pools, and categorizing those species by ecologically meaningful traits (Wetland Indicator Status, functional groups, and biogeographical origin), I investigate how the composition of the soil seed bank could shape plant community response in this system.