Prairie and savanna vegetation of braidwood dunes and savanna nature preserve, Will County, Illinois

Vegetation of the Braidwood Dunes and Savanna Nature Preserve in Will County, Illinois, was studied during the growing seasons of 2004 and 2005. Located in the northeastern part of the Kankakee sand deposits, this site is a small remnant of sand prairie and sand savanna vegetation that once contained extensive marsh, wet, mesic, and dry sand prairie communities. The dry sand prairie was dominated by Schizachyrium scoparium with an Importance Value (IV) of 33.3 (200 possible) followed by Opuntia humifusa and Dichanthelium villosissimum with IV's of 23.9 and 20.3, respectively. In the dry-mesic sand prairie Solidago nemoralis (IV of 24.7) and Schizachyrium scoparium (IV of 23.8) were co-dominant. Two distinct ground layer communities were encountered in the dry-mesic sand savanna, one dominated by Pteridium aquilinum, and one where this species was absent. The dominant overstory species was Quercus velutina along with a few individuals of Q. alba. Woody overstory averaged 188.1 stems/ha, with a basal area of 15.57 m²/ha. A few small sedge meadows occurred in the Preserve. Carex stricta dominated these sedge meadows with an IV of 44.5, with Helianthus grosseserratus, Thelypteris palustris, and Galium obtusum also common. A total of 448 vascular plant taxa were found on the Preserve, 13 fern and fern-allies, one gymnosperm, 120 monocots, and 314 dicots. Fifty-four exotic taxa were encountered, representing about 13 of the species found.