Northern Prairie Wildlife Research Center
Swink and Wilhelm (1979, 1994) developed and later refined a system (floristic quality assessment) for assessing the quality of natural areas in the Chicago region of Illinois. Their system was based on the concept that plant species display varying degrees of tolerance to disturbance, as well as varying degrees of fidelity to specific habitat integrity. They termed this tolerance and fidelity "species conservatism" and assigned each native plant species in the Chicago region a coefficient of 0 to 10 based on its conservatism relative to other native species in the region's flora. Given the assumption that the floristic quality of an area is directly related to its richness in conservative species (Wilhelm and Ladd 1988), the assigned coefficients of conservatism (C values), together with a list of native plant species present in an area, can be used to index the floristic quality of that area (Swink and Wilhelm 1994). Subsequently, floristic quality assessment has been expanded to include Michigan, Missouri, the remainder of Illinois, and northern Ohio (Ladd 1993, Andreas and Lichvar 1995, Taft et al. 1997, Herman et al. 1997), and interest to expand the effort to other regions is growing. Here we provide C values for plant species of North Dakota and South Dakota, excluding the Black Hills, (hereafter referred to as the Dakotas) to facilitate the use of floristic quality assessment in this region and adjacent grasslands.