In the biology of dispersal, a dispersal vector is "an agent transporting seeds or other dispersal units". Dispersal vectors may include factors, such as animals, or abiotic factors, such as the wind or the ocean.
Humans have been acting as dispersal vectors since we began moving around the planet, bringing non-native plants and animals with us. As trends in urbanization have increased, urban environments can act as staging grounds for species dispersal and invasion. Many non-native species exist in urban environments and the high rate of movement in an out of urban areas leads to a high level of dispersal to neighboring environments.