Jacob Anderson, Utah Sate University
Life Sciences
Leafy spurge (LS) is an aggressive Eurasian forb that has been successfully reduced in many areas in western North America through the biological control releases of flea beetles. Long term studies of this phenomenon are sparse. Three flea beetle species were released in the mid-1990s at a site dominated by LS in Richmond, Utah. This study assessed the long term effects of LS biocontrol on an ecological community at this site by addressing five questions: (1) Is LS abundance significantly lower now than in the 1990s? (2) What plant species are replacing LS and are they native or non-native? (3) Have the flea beetle populations persisted since their initial release? (4) What part does soil type play in which flea beetle species now dominate at the site? (5) In response to their unexpected presence, what role may long-horned beetles contribute to the long-term reduction of LS? It was found that LS abundance has significantly decreased from the 1990s; the dominant plant species are those of non-native grasses; flea beetles have persisted in significantly smaller numbers, with Aphthona lacertosa being the most abundant; and long-horned beetles appear to play a significant role in the reduction of sexual success of LS. The results of this project have implications for land managers when considering the vegetative response to LS biological control and the importance of long-horned beetles for long-term in managed, LS-reduced habitats.