| A survey of plant biodiversity was performed along riparian habitats within an agricultural landscape in southeastern Ontario, Canada. The accuracy of several measures of plant biodiversity---including those related to a regional floristic quality assessment system---was examined to compare their ability to recognize a gradient of anthropogenic disturbance and associated floristic quality along the riparian habitats. The "% Non-Native Plant Species" measure was most effective at identifying the gradient, though it revealed nothing about the quality of native plant species at individual sites. The mean conservatism value associated with the floristic assessment system was also effective in identifying the gradient, and had the added benefit of considering the contribution of each native species in a plot. Total plant species richness, the simplest and most common floristic measure applied in the literature, proved to be a relatively poor indicator of the quality gradient. |
