The Distribution of Leafy Spurge (Euphorbia esula) and Other WeedyEuphorbiaspp. in the United States

Abstract

A survey was made in the United States to determine the extent of the infestations of leafy spurge (Euphorbia esula L.) and other weeds of economic importance in the Euphorbiaceae. From introductions about 100 yr ago, leafy spurge is now found in 458 counties in 26 states from coast to coast. The infestations are out of control in some states, and biological control is mentioned as a possible solution to the problem.

Testing the directed dispersal hypothesis: are native ant mounds (Formica sp.) favorable microhabitats for an invasive plant?

“…Seed dispersal relationships are good candidates for facilitative interactions between introduced and native species worldwide (Richardson et al 2000;Pemberton and Irving 1990; Alba-Lynn and Henk 2010), in part due to their lack of specialization and widespread distribution (Howe 1984;Garrido et al 2002). The successful spread of E. esula in its introduced range is often attributed to long-distance dispersal events (Selleck et al 1962;Dunn 1979), with its persistence in local areas due to its highly noxious latex sap, that provides defense from herbivores, and its extensive root system, that allows for re-growth following above-ground damage, and aggressive clonal spread (Selleck et al 1962;Dunn 1979). Our Wndings demonstrate that the native ant community has the potential to inXuence local E. esula patterns of spread through short-distance dispersal events and provisioning of favorable microhabitats that may serve as important foci for invasive plant persistence and spread (Moody and Mack 1988).…”

“…Originally from Europe and Russia (Dunn 1985), E. esula was Wrst detected in North America in Massachusetts in 1827 (Dunn 1979), and has since spread throughout much of North America (Dunn 1985). Euphorbia esula is a clonal, perennial plant capable of producing over 200 seeds per stem (Selleck et al 1962).…”

Plant competition and exclusion with optimizing individuals

“…4A using plant data, the steady-state LAIs are plotted for three species that now occupy rangeland across the Western United States: native grass, which is an aggregate of several perennial grasses including blue grama (Bouteloua gracilis) and big bluestem (Andropogon gerardii); the invasive annual cheatgrass (Bromus tectorum); and the invasive forb leafy spurge (Euphorbia esula). The latter is particularly troublesome because it adapts to a wide variety of habitats (Dunn, 1979;Watson, 1985) and it threatens rangeland productivity, species diversity and wildlife habitats. By 1994 leafy spurge dominated 1.6 million ha of land in the Dakotas, Montana, and Wyoming (Everitt et al, 1995;Bangsund et al, 1999), and it has spread significantly since then.…”

Nutrient composition of soil and plants may predict the distribution and abundance of specialist insect herbivores: implications for agent selection in weed biological control

“…Dunn 1979;Bangsund et al 1999;Richard et al 2000). It is a relatively recent invader into Illinois natural areas, specifically moist prairies.…”