Do chill hours and soil moisture limit the germination of Elaeagnus angustifolia?

Abstract

Invasive exotic species produce impacts of different magnitudes in the environment. The colonization success of a species depends on several factors. Different research demonstrated that chill hours accumulation is one of the most important factors affecting the germination of the tree species Elaeagnus angustifolia L. This non-native species is considered invasive, even noxious, in different parts of the world, modifying terrestrial and aquatic environments. We investigate the chill hours accumulation effect on the seed germination of E. angustifolia under two soil moisture conditions (field capacity and half-field capacity). We also evaluated the survival of seedlings of the species for 240 days under the two mentioned moisture conditions. With the data obtained, we made two heat maps (one for each moisture condition) with the probability of germination of E. angustifolia in Argentina related to the natural availability of chill hours. We found that as the chill hours accumulation increased, germination of E. angustifolia increased in half-field capacity treatment and decreased in field capacity conditions. Seedling survival was 100% in both water regimes. Heat maps show the break dormancy probability of E. angustifolia seeds throughout the Argentine territory, with high potential of germination in Patagonia. In addition to contributing to the prevention of the invasion of E. angustifolia in Argentina, the information generated in our study can be helpful in other regions of the world since the significant genetic variability that the studied species presents can make its environmental distribution range unpredictable.