Environmental Factors Influencing the Spread and Invasion Potential of Arundo donax in Central Texas
Date
2022-12
Authors
Herod, Megan
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Abstract
Invasive species are a global concern and a significant contributor to anthropogenic global change. As invasive species continue to invade new regions, they impact natural ecosystem function and displace native species. The success and impact of invasive species can be tied to species biology and the attributes of the invaded ecosystem. A two-step experimental approach using a greenhouse experiment and remote sensing methodology was used to develop an understanding of the environmental conditions where Arundo donax, a large-statured invasive wetland species, performs best and how it may colonize new areas. I predicted that Arundo would exhibit higher values of performance-related traits such as aboveground biomass (AGB), belowground biomass (BGB), net photosynthesis, and total tiller length under high light, high soil moisture, and high nutrient conditions because there would be fewer factors limiting growth for this species. I also predicted that the spread of Arundo would be closely tied to major flood events when the transportation of propagules downstream and the scouring of banks leads to colonization opportunities. Eight of the eleven response variables analyzed, including AGB, BGB, total tiller length, and net photosynthesis showed a significant interaction between soil moisture and light with plants grown in saturated, high light conditions having the highest values for performance related traits. Nutrients were found to influence biomass allocation patterns, with plants grown with added nitrogen and phosphorous exhibiting higher shoot:root and stem:leaf ratios; however nutrients were not found to significantly influence performance related traits. Major flood events were shown to positively influence the rate of spread of Arundo in the studied stretches of the Guadalupe and Medina rivers in Texas. Understanding how invasive species respond to changes in abiotic factors and what influences their ability to colonize new areas is necessary to make predictions about species expansion and prioritize management efforts and can provide necessary information for the development of ecological models.
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Keywords
invasive species, Arundo donax, giant reed, biomass allocation, nutrient addition, soil moisture, light
Citation
Herod, M. (2022). Environmental factors influencing the spread and invasion potential of Arundo donax in Central Texas (Unpublished thesis). Texas State University, San Marcos, Texas.