Roads as Conduits for Exotic Plant Invasions in a Semiarid Landscape

Abstract: Roads are believed to be a major contributing factor to the ongoing spread of exotic plants. We examined the effect of road improvement and environmental variables on exotic and native plant diversity in roadside verges and adjacent semiarid grassland, shrubland, and woodland communities of southern Utah ( U.S.A. ). We measured the cover of exotic and native species in roadside verges and both the richness and cover of exotic and native species in adjacent interior communities ( 50 m beyond the edge of the road cut ) along 42 roads stratified by level of road improvement ( paved, improved surface, graded, and four‐wheel‐drive track ). In roadside verges along paved roads, the cover of Bromus tectorum…

• BF
  Bayer Fund
• UB
  U.S. Bureau of Land Management