Invasive Species

Invasive species are species of plants (and less commonly, animals) that increase their numbers in natural habitats, displacing existing species and decreasing diversity. Most invasive species are "exotics", species not originally native to a region.


Long-established invasives (they've been around so long, biologists are not entirely sure what they replaced):

  • Ripgut grass (Bromus diandrus)
  • Slender wild oat (Avena barbata)
  • Redstem filaree (Erodium cicutarium)

Invasives currently expanding their extent and density at Cal Poly Pomona:

  • Italian thistle (Carduus pycnocephalus)
  • Mediterranean mustard (Hirschfeldia incana)

Other common invasive plants:

  • Wild oat (Avena fatua)
  • Black mustard (Brassica nigra)
  • Soft chess (Bromus hordeaceus)
  • Red brome (Bromus madritensis)
  • Cheatgrass (Bromus tectorum)
  • Tocalote (Centaurea melitensis)
  • Horehound (Marrubium vulgare)
  • Tumbleweed (Salsola iberica)


There are a number of invasive animals in the urbanized parts of campus, including pigeons (Columba livia), starlings (Sturnus vulgaris), and rats (mainly Rattus rattus), but a species with clear impacts on undeveloped areas is the cat (Felis catus); feral cats are effective "mesopredators" of birds and bird eggs, as well as lizards and native rodents. Coyotes effectively keep the cat population in check.