Have urban stresses led to locally adapted populations of herbaceous species, useful for restoration?

Cities have many sites disturbed by past land-use activities, such as human construction (road-sides), destruction (demolition sites, brownfields) and waste management (landfills). Many native plant species thrive on these habitats. We address the hypothesis that these plants evolved to grow successfully in these harsh urban conditions.  Experimental gardens in the New York-New Jersey Metropolitan area compare the performance of plants propagated from highly disturbed urban communities to plants from rural areas. Five species collected from these sites were used in each of five test gardens representing a gradient from low to high urban stresses.  Several growth and reproductive characters were measured. After two years of growth, the major source of variation in plant performance within each species was the test garden site. These have different soil characteristics such as quantity of rubble in the substrate, exposure to sun, and soil evaporation rate. There is also some effect of the source of the plant seeds, and it is site-specific. This approach may be useful to uncover populations for urban restoration planting materials, as certain stressed sites require seed or plants derived from similarly stressed provenances.