Alkaline Fens Research Articles

Summer foraging patterns and diet selection of muskrats inhabiting a fen wetland

Foraging patterns, dietary preference, and diet quality of muskrats (Ondatra zibethicus) were studied at an alkaline fen in northern New York, from May 1985 to August 1986. Cattail (Typha latifolia) was the most prominent plant food item in the diet of muskrats. Feedbed surveys indicated that muskrat foraging bouts decreased from the lakeshore denning area with distance into the fen. This pattern of reduced feeding activity was associated with declines in both open water travel routes (i.e., sluiceways) and cattail biomass. Muskrats preferentially selected the core of the cattails. Tissue assays showed core tissue to contain low amounts of lignin and only moderate levels of cellulose, suggesting that muskrats were selecting the plant part most easily digested. Nitrogen and phosphorus levels in cattail samples from all sampling locations in the fen were similar, suggesting that muskrats concentrated their foraging movements for reasons other than maximizing diet quality. These data suggest that predator avoidance behavior strongly influenced muskrat foraging movements, and that muskrats attempted to maximize feeding efficiency within the constraint of access to available open water escape routes.

Woody Vegetation and Microtopography in the Bog Meadow Association of Cedar Bog, a West-central Ohio Fen

The bog meadow association, a fen at Cedar Bog Nature Preserve in W-central Ohio, was studied to determine the short range establishment potential of woody species, especially arbor vitae (Thuja occidentalis). The presence of numerous arbor vitae seedlings and saplings, a 54% winter survival rate of seedlings, and possible invasion of the meadow by peripheral arbor vitae via branch-layering suggest that this tree species is invading the bog meadow. This vegetation change is thought to be recent and indicates succession of the bog meadow toward an arbor vitae forest. Active management of the vegetation in the preserve is recommended to maintain the bog meadow association as an herb-dominated fen. INTRODUCTION Cedar Bog Nature Preserve, Champaign Co., Ohio, contains a 20-ha relict of what was formerly a 2800-ha complex of wetlands and forest in W-central Ohio. Many of the plant species in the preserve occur S of their normal range, and Braun (1950) considered Cedar Bog to be the most southerly of the well-preserved bog remnants in North America. It is the only remaining alkaline fen in Ohio (Forsyth, 1974). As such, the area is an important relict of the rapidly disappearing northern wetlands. Frederick (1974) identified six plant associations in the preserve: bog meadow, marl meadow, arbor vitae, swamp forest, shrub and hardwood forest. The most ubiquitous tree species is arbor vitae (Thuja occidentalis') which is present in all associations except the hardwood forest. Frederick (1974) found small arbor vitae trees growing on many of the larger hummocks near the margins of the bog meadow. Braun (1928) hypothesized that portions of Cedar Bog were undergoing succession from bog meadow through an arbor vitae stage, and eventually developing into hardwood forest. If this is true, arbor vitae should be successfully invading treeless associations such as the bog meadow. The soil of the bog meadow association is an alkaline, wet marl resulting from groundwater which surfaces after passing through dolomitic glacial deposits (Forsyth, 1974). Therefore, this association is correctly classified as a fen, a type of vegetation which has been considered a precursor to bog and swamp forest communities (Moore and Bellamy, 1974). The meadow contains closely spaced hummocks of low elevation (< 0.5 m high) and 0.5-1.5 m in diam, which produce microenvironmental gradients from wet marl between hummocks to Carex-Sphagnum covered hummock tops. Invasion and establishment of woody species may be related to the microenvironmental gradients associated with these hummocks. The purposes of our study were to: (1) describe the woody vegetation in the bog meadow association; (2) evaluate the potential increase of woody species, especially arbor vitae, in the meadow, and (3) relate distribution of woody species to microtopographic position. MATERIALS AND METHODS Six belt transects 2 m wide and varying in length from 7.5-45 m were located 1 Department of Botany and Microbiology, University of Oklahoma, Norman 73019. 2 Perino & Associates, 900 West Lake Drive, Springfield, Illinois 62707. 1 Nomenclature follows Weishaupt (1971).

Manganese-phosphate reactions in aqueous systems and the effects of applications of monocalcium phosphate, on the availability of manganese to oats in an alkaline fen soil

Electrometric titrations and chemical analyses of aqueous systems containing manganese sulphate and phosphoric acid showed that the compositions of manganese phosphates formed at various pH values depended on initial manganese concentrations and Mn : P molar ratios. The results show how phosphate benefits crops on soils containing toxic levesl of manganese.

STUDIES ON SOIL MANGANESE

Summary1. While results of extractions, performed in the presence of reducing agents, of mineral soils low in organic‐matter content suggested that manganese higher oxides approaching the manganese‐dioxide type are present or formed by oxidation of added manganese, results obtained with other extractants lend support to the suggestion by Dion and Mann that hydrated manganese oxides may occur in such soils.2. From the distribution of manganese in various extracts of alkaline organic soils with or without added manganese materials, it was concluded that no difficultly reducible higher oxides of manganese are present or formed. Some evidence was presented for the view that manganese of a higher valency form may remain in combination with the organic matter or may be retained in this manner after oxidation of added manganese.3. Divalent manganese present as a complex of the organic matter of alkaline organic soils could be estimated by extraction with a monocalcium disodium versenate solution. It constituted 10–20 per cent. of the total manganese content. Manganese added to such soils and not present as readily soluble manganese was recovered by this extractant shortly after application; manganese did not, however, remain in this form after some weeks contact with soils.4. The organic matter of various soluble organic‐matter fractions migrated anionically over a wide pH range; that of lignin solutions remained at the iso‐electric point. Manganese already present in soluble organic‐matter fractions migrated anionically in contrast to manganese added and retained by such fractions that moved predominantly as a cation.5. The oxidizable carbon or total nitrogen content of soluble organic‐matter fractions was not closely related to the amounts of manganese retained by such fractions in a form that was non‐dialysable against potassium chloride. Some evidence was obtained that different types of complexing groups may be present in water extracts subsequent to extraction by sodium chloride of an alkaline fen and of an acid raw‐humus peat.