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The Role of Nutrients in Accelerating Invasion by Red Canary Grass
A Report of the Research Sponsored in Part by the Illinois Native Plant Society 28 February 2003
Kathy Papp, Dennis Nyberg Department of Biological Services, University of Illinois Chicago
ABSTRACT
Pharlaris arundinacea (reed canary grass) is the most common invasive species threatening diversity of Illinois wetlands. Increased nitrogen deposition and high nutrient levels are associated with weedy plants. To study the effects of nutrients on the invasion of P. arundinacea into wetlands we constructed mesocosms planted with four native species (Carex aquatilis, C. lacustris, C. stricta and Calamagrostis Canadensis). After establishment, five seedlings and seed of P. arundincea were added. Ammonium nitrate equivalent to a total of 5.0 g.m-2.yr-1 N or sugar ( 500 g.m-2.yr-1C) were applied as treatments for 20 weeks to six replicate pots each. Six pots received no nutrients. At the end of the first growing season P. arundinacea individuals were too immature to reliably harvest. All species were harvested and weighed at the end of the second growing season. The average biomass of the native species in 2002 (450 g/pot = 775 g.m-2 was not effect by the nutrients, but the average dry weight of P. arundinacea was. The sugar added pots had only 0.2 g/pot, while P. arundinacea averaged 1.9 g/pot in the control and 4.8 g/pot in the 6 pots receiving nitrogen. The results suggest that the addition of carbon to wetlands should be considered to control invasion of native communities by P. arundinacea . |
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Status and Distribution of Known Populations of Stenanthium gramineum (Ker) Morong (grass-leaved lily) Liliaceae: An Endangered plany in Illinois.
Report to Illinois Native Plant Society for Research Project. August 2002
Bob Edgin
ABSTRACT
Stenanthium gramineum (Ker) Morong (grass-leaved lily) Liliaceae is a perennial herb with a slender, glabrous stem that is slightly bulbous at the base and up to 1.7 m tall (Fernald 1950, Gleason and Cronquist 1991, Mohlenbrock 1970). The leaves are cauline, linear, up to 40 cm long, 3 cm broad, and ascending with the upper becoming much reduced. The inflorescence is a terminal elongated panicle 40-75 cm long. The race miform lower branches have wholly staminate, or rarely perfect, whitish or greenish flowers. The terminal unbranched spiciform axis has a sessile to pedicellate perfect flowers. The flowers have 6 narrowly lanceolate, long-aciminate tepals that are 5-10 mm long, adinate to the ovary base and appear from mid-June through mid-August in Illinois. The ovary is ovoid, deeply 3-lobed, each lobe prolonged into a short, stout outcurved style. The capsule is 3-lobed, ovoid, septicidal, and 8-14 mm long. The seeds are lanceloid, 3-8 mm long. Herkert(1991) reports that Stenanthium gramineum (grass-leaved lily), a state endangered species, is known from only three counties in Illinois. This study was prompted by the discovery of a previously unreported population of Stenanthium gramineum at Big Creek Woods Memorial Nature Preserve, Richland County during a floristic study of the site in 2000 and 2001 and the discovery of a population from which O’Dell had collected a voucher specimen in 1943. These findings suggested that other populations of the grass-leaved lily may persist at sites that are now considered as historic records. The objectives of this project were fourfold: 1) to visit all known and historic Stenanthium gramineum sites in Illinois to verify the presence or absence of those populations; 2) record information regarding habitat characteristics including aspect, topographic position of the population, associate species, soil type, tree density, and percent canopy cover; 3) record population information including number of individuals and % of individuals that produce flowers, fruits, and seed; 4) gather information on reproductive strategies and potential by examining seed production. |