PS 12-139 - Disturbed landscapes and autumn olive: Implications for expanded invasion in response to increasing environmental pressure

Monday, August 7, 2017
Exhibit Hall, Oregon Convention Center


Windy Kelley, Smith College; Danielle Ignace, Smith College


Plant species are known to change biophysical traits in response to extreme events. Abiotic factors including temperature, soil composition and level of disturbance, convert landscapes from their natural state. As ecosystems rebuild, non-native plants use this transition to seek out available resources and displace native species. Invasive plants may possess specialized abilities to capture and utilize resources more efficiently than native plants. This unique ability may allow invasive plants to maximize underground biomass, form specific berry/seed characteristics and conserve resources more efficiently. How abiotic factors impact biophysical change is necessary for understanding effects of climate change on growth success rates, competitive advantages and expanding invasion of invasive plants. I investigated how temperature, soil composition and disturbance impact roots structure and berry/seed formation of a dominant invasive plant, Elaeagnus umbellata (Autumn Olive). Differences in plant characteristics were investigated by collecting autumn olive samples from disturbed habitats in Western Massachusetts. These sites were expected to differ by soil composition, level of disturbance, temperature/precipitation. Starting in October 2014 to September 2016, shrub and berry samples were collected from each of the sites. Goals for collecting samples enabled an in depth exploration into expected variances in plant characteristics between disturbed habitats.


Mean temperature and precipitation measurements demonstrate significant differences between sites. Root nodule abundance and root length demonstrated significant differences between sites. Warmer, less disturbed sites had significantly greater proportions of root nodule weight in relation to root weight, as well as root nodule abundance. Seed dry weight, whole berry weight and circumferences also demonstrated significant differences among sites. Larger, heavier berries were collected from less disturbed sites. 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. Soil analysis show significant differences in percent of organic layer, estimated release of nitrogen and phosphorus between a roadside site 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. This research addressed how disturbance, changes in temperatures and soil characteristics may benefit Autumn Olive. Warmer temperatures and nutrient-poor soils, in turn may facilitate robust root structures and greater nodule presence along with more robust berry/seed growth. This research presents valuable information on the ability of Autumn Olive to adapt to increasing abiotic pressures.