Open Access. Powered by Scholars. Published by Universities.®
Science and Mathematics Education Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 5 of 5
Full-Text Articles in Science and Mathematics Education
Age And Developmental History Of Iowa Fens, C. A. Thompson, E. A. Bettis Iii
Age And Developmental History Of Iowa Fens, C. A. Thompson, E. A. Bettis Iii
Journal of the Iowa Academy of Science: JIAS
Iowa fens are small, mineorotrophic peatlands maintained by shallow groundwater. Eighteen fen sites located across northern Iowa were mapped and radiocarbon dated to assess the timing of initial peat accumulation. The radiocarbon ages span the Holocene, ranging from 1,240 to 10,900 B.P.; however most fens postdate 5,000 yr B.P. The dominance of late-Holocene ages suggests that Holocene climatic change may have strongly influenced the record of peat accumulation. During the mid-Holocene Iowa was warmer and drier than at present, and peat was degraded or accumulated slowly in fens. The range of ages also implies that the commencement and subsequent rate …
Geology Of Iowa Fens, C. A. Thompson, E. A. Bettis Iii, R. G. Baker
Geology Of Iowa Fens, C. A. Thompson, E. A. Bettis Iii, R. G. Baker
Journal of the Iowa Academy of Science: JIAS
Fens are peatlands which are dependent on groundwater discharge to provide nutrient enrichment. Fens are found in a variety of landscape positions and in most Iowa landform regions. This paper presents a classification system for Iowa fens based on landscape position, stratigraphy, and hydrologic factors. Iowa fens can be separated into six categories: 1) fens along valley wall slopes; the groundwater source for these fens is sand and gravel buried between glacial tills (inter-till); 2) fens in hummocky topography on the northwestern margin of the Des Moines Lobe landform region; the water source is sand and gravel buried within glacial …
Floristic Composition And Conservation Status Of Fens In Iowa, John A. Pearson, Mark J. Leoschke
Floristic Composition And Conservation Status Of Fens In Iowa, John A. Pearson, Mark J. Leoschke
Journal of the Iowa Academy of Science: JIAS
Over 200 extant fens of varying condition were documented during an extensive inventory conducted in Iowa between 1986 and 1991. Approximately half of the extant fens support endangered, threatened, special concern, or other rare plant species. Approximately 25 fens are outstanding conservation prospects with intact vegetation, high species richness, and rare species. Nearly 40% of all potential fen sites have been destroyed by cultivation or damage; another 30% remain unknown due to lack of a field visit, but most appear on aerial photographs to be very small, disturbed fragments. In addition to their traditionally recognized range in northwest Iowa, fens …
Rare Iowa Plant Notes From The R. V. Drexler Herbarium, Jeffery C. Nekola
Rare Iowa Plant Notes From The R. V. Drexler Herbarium, Jeffery C. Nekola
Journal of the Iowa Academy of Science: JIAS
Notes on the distribution, habitats, associated species, and taxonomic considerations for 134 rare Iowa plants are presented. These taxa, including 15 Pteridophytes, 74 Dicots, and 45 Monocots were located during a decade of field research (1979-1989) concentrated in eastern, northeastern, and northwestern Iowa. Included among these are 10 taxa previously unrecorded from the Iowa flora (Carex sterilis, Circaea X intermedia, Cypripedium calceolus var. parviflorum, Lycopodium inundatum, Opuntia macrorhiza, Salix candida X Salix rigida, Salix X clarkei, Solidago uliginosa, Spiranthes ova/is, Viola adunca), and 15 taxa (Angelica atropurpurea, Aristolochia serpentaria, Artemesia frigida, Aster linariifolius, Berula pusilla, Carex conoidea, Eleocharis pauciflora var. …
Diatoms (Bacillariophyceae) From The Excelsior Fen-Complex, Dickinson Co., Iowa, With The Description Of Two New Taxa, Charles W. Reimer
Diatoms (Bacillariophyceae) From The Excelsior Fen-Complex, Dickinson Co., Iowa, With The Description Of Two New Taxa, Charles W. Reimer
Journal of the Iowa Academy of Science: JIAS
This paper presents a summary list of the presently known diatom flora of the Excelsior Fen-complex and a description of two new taxa: Navicula incompta var. incurva Reim. var. nov. and Stauroneis bovbjergii Reim. sp. nov. Notes on some physico-chemical parameters of the habitat and on the ecology of the taxa are included.