PS 5-68 - Competitive advantages of Autumn Olive: Implications for expanded invasion in response to increasing environmental pressures

Monday, August 8, 2016
ESA Exhibit Hall, Ft Lauderdale Convention Center
Windy Kelley, Biological Sciences, Smith College, Northampton, MA and Danielle D. Ignace, Ph.D., Department of Biological Sciences, Smith College, Northampton, MA

Plants have been known to change biophysical traits in response to extreme variations in temperature and soil composition. Once landscapes are converted from their natural state, non-native plants seek out available resources and displace native species. Invasive plants may possess a specialized ability to maximize underground biomass that allows for them to capitalize on these disturbed habitats. How abiotic factors impact underground biophysical change is a necessary component to understanding the effects of climate change on growth success rates, competitive advantages over native communities and expanding geographic ranges of invasive plants. We investigated how temperature, soil composition and characteristics impact the biophysical changes in roots and nodule structure of a dominant invasive plant, Elaeagnus umbellata (Autumn Olive). Differences in underground root architecture were investigated by collecting autumn olive biomass from five disturbed habitats, along a natural temperature gradient in Western Massachusetts. These sites were expected to differ by soil composition and temperature. Starting in October through to December 2015, ten samples were collected from each of the five sites. Our goals for collecting samples enabled an in depth exploration into expected variances in root characteristics between disturbed habitats. We analyzed samples for root nodule size, abundance, and proportion of root weight, as well as rooting structure characteristics. 


Root nodule abundance, root length and maximum diameter demonstrated significant differences between sites. Warmer abandoned sites had significantly greater proportions of root nodule weight in relation to root weight, as well as root nodule abundance. Mean temperature measurements demonstrate a difference between sites at higher and lower elevations, with data indicating lower elevations are warmer. Root length and maximum diameter were significantly greater in both the warmer construction site and a cooler roadside site, suggesting soil characteristics may play a larger role. A preliminary soil composition analysis suggests significant differences in percent of organic layer between a roadside pull off and an old-field habitat. The roadside habitat showed significantly less organic matter, along with decreases in other soil nutrients. These results suggest changing soil composition between differing types of disturbed habitats. Our research addressed how disturbance, changes in temperatures and soil characteristics may benefit Autumn Olive providing an elevated competitive advantage over native species. Warmer temperatures and nutrient-poor soils, in turn may facilitate robust root structures and greater nodule presence. Our research presents valuable information on the ability of Autumn Olive to adapt to increasing abiotic pressures.