Date of Award
2023
Document Type
Dissertation
Degree Name
Ph.D.
Organizational Unit
College of Natural Science and Mathematics, Biological Sciences
First Advisor
Anna A. Sher
Second Advisor
Shannon M. Murphy
Third Advisor
Patrick H. Martin
Fourth Advisor
Erica L. Larson
Fifth Advisor
Eduardo González-Sargas
Sixth Advisor
Rebecca Powell
Keywords
Biological invasions, Lidar, Meta-analysis, Restoration ecology, Salix, Tamarix
Abstract
Control of invasive Tamarix spp. in riparian systems has long been a priority for management in western North America, but questions remain regarding the response of the broader plant community to different treatments. Here we summarize a series of approaches at different scales to quantify the effects of Tamarix control on characteristics of this ecosystem, including provisioning of wildlife habitat. In the first chapter we analyzed findings of the last 20 years using meta-analysis and found that although treatment has been successful in reducing Tamarix and promoting native vegetation to some extent, most literature reports very small effect sizes and there are still knowledge gaps. Specifically, questions remain around whether the tree/shrub species and/or functional groups that replace Tamarix following treatment can provide adequate bird habitat. Thus, in the second chapter we quantified the effect of Tamarix control on recovery of Salix (willow) spp.; species in this genus have a similar biomass distribution to Tamarix, which allows them each to provide habitat for cup-nesting birds of special interest. We found that (1) while a decrease in Tamarix is associated with an increase in Salix under some treatment and environmental conditions, Salix did not fully replace Tamarix as a dominant woody species, and (2) while treatment methods were overall not strong predictors of Salix regrowth, application of herbicide to invasive vegetation was associated with increased positive change in Salix cover. To investigate broader-scale dynamics around bird habitat provisioning in this system, in the third chapter we sought to determine whether morphology of the entire overstory is affected by treatment actions and environmental characteristics using lidar data. We found that active reintroduction of native trees is associated with higher density of biomass after sufficient time for secondary succession, thus likely to provide superior habitat than other restoration approaches. Our results provide insight into post-restoration trajectories of a novel ecosystem and show that it is possible, albeit difficult, to promote wildlife conservation through planned management of invasive vegetation.
Publication Statement
Copyright is held by the author. User is responsible for all copyright compliance.
Rights Holder
Alexander R. B. Goetz
Provenance
Received from ProQuest
File Format
application/pdf
Language
en
File Size
171 pgs
Recommended Citation
Goetz, Alexander R. B., "Plant Community Response to Control of a Dominant Invader at Multiple Scales" (2023). Electronic Theses and Dissertations. 2243.
https://digitalcommons.du.edu/etd/2243
Copyright date
2023
Discipline
Ecology