Paul B. Marcum

Prairie and Savanna Vegetation of Braidwood Dunes and Savanna Nature Preserve, Will County, Illinois

ABSTRACT 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 IVs 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.

A Floristic Inventory and Vegetation Survey of Three Dolomite Prairies in Northeastern Illinois

ABSTRACTu2003 Dolomite prairies are rare natural plant communities, with a few high-quality examples in northeastern Illinois. In this study, three dolomite prairies located in southwestern Will County, Illinois, were surveyed to assess species composition and quality. Two of the dolomite prairies were located on the Des Plaines Wildlife Conservation Area (i.e., Blodgett Road Dolomite Prairie Natural Area and Grant Creek Nature Preserve) and the third in the Midewin National Tallgrass Prairie (i.e., Exxon Mobil Natural Area). Overall, a total of 438 taxa were recorded: 318 at Blodgett Road, 255 at Exxon Mobil, and 270 at Grant Creek, with 129 common to them all. Of these, 97 were mesic or wet prairie species, 26 were nonnative taxa, and six were native woody species. Three state endangered and two state threatened species were found associated with these dolomite prairies. The Blodgett Road site was dominated by the annual grass Sporobolus vaginiflorus, along with Andropogon gerardii, Sporobolus heterolepis, and Ambrosia artemisiifolia. The Exxon Mobil site was dominated by the exotic species Poa compressa and Daucus carota, and several native taxa including Sporobolus vaginiflorus, Allium cernuum, Andropogon gerardii, and Solidago altissima. The Grant Creek location was dominated by Sporobolus heterolepis, Rosa carolina, Sorghastrum nutans, and Solidago altissima. These three dolomite prairies can be considered good quality natural areas based on species richness and floristic quality. However, the presence and occasional dominance of nonnative species suggests the need for implementation and continuation of management practices that should maintain or improve their quality.

Vegetation of Hooper Branch Nature Preserve, Iroquois County, Illinois

Abstract n The Hooper Branch Nature Preserve is located in the extensive dune and swale topography of the sand deposits of northeastern Illinois. The plant communities present at the time of this survey were similar to those of pre-settlement times. The vegetation associated with the dunes had not been disturbed except for past grazing; the swales, in contrast, were drained and farmed before the area was dedicated in 1986. Dry and dry-mesic sand savanna was associated with the dunes where Quercus velutina (Black Oak) accounted for 75% to 97% of the importance value in the savanna. Carex pensylvanica (Pennsylvania Sedge) was the dominant ground cover species usually followed by Schizachyrium scoparium (Little Bluestem). In parts of the preserve that had been most recently burned, woody species were more common in the ground layer, with the most important being Q. velutina seedlings, Rhus copallina (Dwarf Sumac), and Rubus allegheniensis (Common Blackberry). A 3-ha flatwoods in the Preserve was dominated by Q. palustris (Pin Oak), which accounted for nearly 95% of the overstory.

Vascular Flora of Iroquois Woods Nature Preserve, Kankakee County, Illinois

Abstract The Iroquois Woods Nature Preserve, located just south of Aroma Park, Kankakee County, is in the Kankakee Sand Area of northeastern Illinois. Three relatively distinct topographic zones exist within the preserve (low terrace, shallow depression, high sand terrace). The forest overstory in all three zones, however, is very similar with most of the same species occurring in each zone, but in different densities. These natural communities are probably due to elevation, distance from the river, soil moisture, and erosion due to flooding events. In the low terrace (mesic sand forest), located near the edge of the Iroquois River channel, Quercus rubra, Tilia americana, Ulmus rubra, Aesculus glabra, and Q. macrocarpa dominate, with the oaks in the larger diameter class. In the shallow depression (wet-mesic sand forest) behind the low terrace Quercus bicolor dominated with 50 stems/ha and accounted for almost half of the total basal area. Tilia americana and U. americana were second and third in importance due to the large number of small diameter individuals. East of the depression was a high sand terrace (dry-mesic sand forest) dominated by Q. alba followed by U. americana, Q. velutina, Prunus serotina, and Q. rubra. This preserve contains one of the few examples of high quality mesic sand forests in the state, but oak regeneration is limited, and shade-tolerant species are becoming more abundant.

Lythrum hyssopifolia L. (Hyssop Loosestrife or Grass Poly, Lythraceae): A New Species in the Illinois Flora

ABSTRACTu2003 The first occurrence of Lythrum hyssopifolia L. (hyssop loosestrife or grass poly, Lythraceae) is documented for Illinois. This Old World native is presently known from every continent except Antarctica with its North American distribution limited to thirteen states within the United States as well as two Canadian provinces.

Vegetation of forest and savanna communities on glacial sand deposits in Northeastern Illinois

Abstract Pembroke Township, Kankakee County, Illinois, is part of an extensive glacial sand deposit. In this part of Illinois, some sand savannas retain much of their original natural character and they have high diversity; we detected 574 taxa of plants, including 11 state-listed endangered and threatened species. On five sites, we evaluated vegetation that varied from dry sand savanna to closed sand forest with Quercus velutina (black oak) dominating the overstory and Q. alba (white oak) the only other species of tree commonly encountered. Density of trees averaged 135.7 stems/ha, with an average basal area of 7.94 m2/ha on our five sites. Based on aerial photographs, the extent of woody overstory has more than doubled since 1939.

Vascular Flora and Woody Plant Structure and Composition at Gooseberry Island Nature Preserve, Kankakee County, Illinois

Abstract A survey of vascular plant species at Gooseberry Island Nature Preserve, a 5.56 ha forested island, was conducted during the 2004 growing season. This study was undertaken to document the composition and structure of the vascular flora and to provide baseline information for land management decisions. A young second growth wet floodplain forest and an old-growth mesic floodplain forest community was quantitatively sampled. The wet floodplain forest community was dominated by Acer saccharinum (silver maple) with some Salix nigra (black willow). The mesic floodplain forest was dominated by Aesculus glabra (Ohio buckeye), Acer saccharum (sugar maple), and Quercus macrocarpa (bur oak). Bur oak, a dominant species in the largest tree size classes, was only a minor element in the lower tree size classes and was absent from the shrub and sapling layers. Historical data from 1977 indicate that in the last 30 years there has been a significant increase in buckeye and sugar maple. A total of 162 species in 126 genera and 62 families were encountered, including 35 taxa near the northern limits of their range.