Distribution of Botrychium campestre in Northeastern Iowa

Abstract

-A survey of 42 glade sites in northeastern Iowa documented the occurrence of the northern plains Botrychium campestre at 12 sites. These populations represent a 200-350 km eastern range extension into a habitat previously unreported for this taxon. The presence of B. campestre with other northern plains disjuncts in the flora of these sites suggests that eastern Iowa glades may represent refugia for taxa whose ranges were more extensive during the Hypsithermal. Botrychium campestre W.H. Wagner & Farrar initially was located in 1982 in the Loess Hills of western Iowa. While at first believed to represent a Loess Hills endemic (Howe et al., 1984), subsequent investigation revealed it to occur in dry gravel or loess prairie sites from extreme southwestern Iowa to central Alberta (Lellinger, 1985; Wagner and Wagner, 1986; Coffin and Pfanmuller, 1988). Disjunct populations of this species also have been found in grasslands on beach dunes or on thin soil over bedrock along the eastern, western, and northern shores of Lake Michigan, Lake Huron, and the southern shore of Lake Superior (Wagner and Wagner, 1993). Although the most recent range map for this species (Wagner and Wagner, 1993) shows this taxon entering eastern Iowa, until now no populations were known east of Dickinson County in extreme northwestern Iowa (Peck et al., 1989). A single population of B. campestre was located in May 1993 on a limestone glade southwest of Rockford in Floyd County, Iowa. This station represented a 200 km range extension eastward into a previously undocumented habitat for this species. During May of 1994 and 1995, 42 additional glade sites, spread across 17 northeastern Iowa counties, were surveyed. Populations of B. campestre were located at 12 sites in 10 counties (Fig. 1). All specimens are housed in the R.V. Drexler Herbarium (COE) at Coe College, in Cedar Rapids, Iowa. SPECIMENS EXAMINED. (numbers cited are COE accession numbers)-Black Hawk Co., Pints Quarry Glade, SE?/4 SW14 SE4 SE14 Sec. 36, T89N R12W, Nekola & Schlicht s.n. (COE 10738); Butler Co., Austinville Glade, NW/4 NW/4 SW/4 SWW Sec. 19, T90N R18W, Nekola & Schlicht s.n. (COE 10739); Clinton Co., Maquoketa South Glade, N2 SW1/4 NW, SW/4 Sec. 5, T83N R3E, Nekola s.n. (COE 10875); Delaware Co., Earlville Glade, SW'4 NW/4 NW1/4 SW/4 Sec. 4, T88N R4W, Nekola s.n. (COE 10750); Floyd Co., Beemis Creek This content downloaded from 157.55.39.35 on Thu, 01 Sep 2016 05:37:34 UTC All use subject to http://about.jstor.org/terms AMERICAN FERN JOURNAL: VOLUME 86 NUMBER 4 (1996) = Botrychium campestre present O = Botrychium campestre absent = Unsurveyed glade site lI = lowan Erosional Surface L: = Des Moines Lobe ii = Paleozoic Plateau , i = Mississippi River Alluvial Plain mi = Southern Iowa Drift Plain FIG. 1. Map of the northeastern third of Iowa showing county and physiographic region boundaries, with the location of glade sites inventoried for B. campestre. Open circles designate sites in which B. campestre was absent; filled circles sites in which B. campestre was present. Glade, SW4 NW/4 NW14 NW1/4 Sec. 6, T94N R18W, Nekola & Horton s.n. (COE 10700, 10741); Franklin Co., Hampton East Glade, NE/4SE/4 NE1/4NW1/4 Sec. 6, T91N, Nekola & Schlicht s.n. (COE 10740); Howard Co., Florenceville Glade, SW/4 SW/4 NW/4 NE/4Sec. 27, T100N R11W, Nekola s.n. (COE 10766); Jackson Co., Hamilton Glade, NE/4 SE1/4 NE1/4 Sec. 23, T84N R3E, photo voucher, Nekola & Hamilton s.n.; Linn Co., Baty Glade, NE4 NE/4 SW/4 SW1/4 and NE/4 SE/4 SW/4 Sec. 10, T86N R7W, J. Nekola & F. Nekola s.n. (COE 10731, 10732); Matsell Bridge Glade, SW4 NE /4SE/4 SE/4 Sec. 26, T85N R5W, Schlicht s.n. (COE 10775); Troy Mills Quarry Glade, SW1/4 SE/4 NW1/4 SE/4 Sec. 9, T86N R7W, Nekola s.n. (COE 10776); Winneshiek Co., Ludwig Glade, NE/4 NE/4 SW/4 NW/4 Sec. 25, T97N R1OW, Nekola (COE 10767). Individuals of B. campestre from eastern Iowa (Fig. 2) appear on average to be slightly smaller than typical material from western Iowa (see Wagner and Wagner, 1986, fig. 5). It is not clear if this difference is related to genetic or ecotypic factors, or a combination of both. By far the largest population observed was that at Beemis Creek, where at least 52 individuals were noted. 120 This content downloaded from 157.55.39.35 on Thu, 01 Sep 2016 05:37:34 UTC All use subject to http://about.jstor.org/terms NEKOLA & SCHLICHT: DISTRIBUTION OF BOTRYCHIUM CAMPESTRE