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Field and laboratory studies were conducted to evaluate the use of bacterial growth on aquatic insects as a metric for determining the existence of nutrient impacts in wetlands. Results from field investigations indicated that elevated concentrations of nitrate and phosphate were associated with growth of filamentous bacteria on insect body surfaces and that there were significantly fewer mayflies...
We developed a surface-associated activity trap (SAT) for sampling aquatic invertebrates in wetlands. We compared performance of this trap with that of a conventional activity trap (AT) based on nondetection rates and relative abundance estimates for 13 taxa of common wetland invertebrates and for taxon richness using data from experiments in constructed wetland. Taxon-specific non-detection rates...
In five tributary streams (four inflowing and one outflowing) of 1600-ha Trout Lake in northern Wisconsin, USA, we examined factors that can affect the magnitude of stream flow and transport of dissolved organic and inorganic carbon (DOC and DIC) through the streams to the lake. One catchment, the Allequash Creek basin, was investigated in more detail to describe the dynamics of carbon flow and to...
Although the importance of hydrology to wetland ecosystem productivity is recognized, there are few detailed analyses of shallow subsurface water flow (<1 m depth) through wetland ecosystems. Shallow subsurface water flow paths and average linear velocity were quantified with nested lysimeters in a riverine wetland located in Hale County, AL. Water-table elevation was spatially and temporally variable...
Hydrology and water quality distributions in a Louisiana forested waste-water treatment wetland were studied under four different hydraulic loading rates (HLR). Pond discharge, surface-water elevations, and fluorescent dye travel times were recorded to assess surface-water hydrology and water samples were collected for nitrate, ammonium, phosphate, and suspended solids analyses. Wetted surface area...
We studied the relationship between benthic invertebrates and aquatic birds at a newly constructed wetland using an avian exclosure experiment combined with counts of aquatic bird use. We measured the standing stock biomass of benthic dipterans both inside and outside exlosures. Chironomidae was the most abundant dipteran family present. Maximum chironomid standing stock biomass per pond ranged from...
The placement of wetland restoration projects in a landscape to optimize the functional performance of wetlands on a regional scale is often overlooked. To address this problem, the U.S. Environmental Protection Agency’s Landscape Function Project developed the synoptic approach to assign restoration priority to landscape subunits according to selected functional criteria. The approach provides a...
Factors affecting growth of softstem bulrush (Scirpus validus), an obligate wetland plant frequently used in subsurface-flow constructed wetlands in North America, were studied in a controlled environmental chamber. Effects of media depth (30-and 46-cm), hydraulic retention time (HRT) (2- and 6-day), and water-level drawdown (drawdown vs. no drawdown) on plant growth in 24 microcosms were investigated...
Size, shape, orientation, and distribution of tree islands in a remnant of northern Everglades wetland were examined from 1950 and 1991 aerial photography. The objectives were to quantify the patterns of tree islands in Loxahatchee National Wildlife Refuge, to determine if the patterns of tree islands had changed between the two dates, and to relate the tree island patterns to modeled pre-and post-drainage...
Sediment organic matter content, bulk density, and hydraulic conductivity were examined in 56 sediment cores collected from a small lotic wetland in the Talladega Wetland Ecosystem (Hale County, Alabama, USA). All sediment characteristics varied spatially across the wetland. A distinctive demarcation in sediment characteristics occurred between the upper (0 to 30-cm) and lower (30 to 80-cm) depths...
Dead, downed wood is an important component of upland forest and aquatic ecosystems, but its role in wetland ecosystems, including mangroves, is poorly understood. We measured downed wood in ten sites on the western Pacific islands of Kosrae, Pohnpei, and Yap, all located within the Federated States of Micronesia. Our goals were to examine patterns of variability in the quantity of downed wood in...
Sulfur transformations in freshwater peat were studied using contrasting stable isotope signatures of atmospheric input (high δ34S) and Sphagnum peat substrate (low δ34S). Wet subsurface peat samples from the Lehstenbach watershed, Fichtelgebirge, Germany were incubated anaerobically at 5 and 15°C. Pore-water sulfate was augmented with natural precipitation at the onset of the experiments. Sulfate...
We described the vegetation of two alluvial swamp forest stands along Durham Creek in Beaufort County, North Carolina, USA in relation to elevation, hydrologic, and edaphic gradients. Over 3,000 surveyed elevations of individual plant microsites were used in conjunction with 26 years of stream gage data to examine individual species responses to annual and growing season flooding frequencies. Direct...
Studies have documented the flora, fauna, and soils of ground-water fed wetlands, but very little is known about their plant-mycorrhizal associations. This study was designed to determine the presence of arbuscular mycorrhizal (AM) fungi in several wetland plant species associated with fens in west central Ohio, USA. Roots of wetland plant species collected at four sites had mycorrhizal fungal colonization...
The U.S. Fish and Wildlife Service and Canadian Wildlife Service incorporate information from annual aerial and ground counts of waterfowl into harvest management strategies. Timing of population surveys is thought to be optimal for early nesting species but may not reliably reflect the status of species with later migration chronology. The purpose of this study was to evaluate effects of survey timing...
The Everglades crayfish (Procambarus alleni Faxon) is the only species reported from Everglades National Park (ENP) and Big Cypress National Preserve (BICY). However, we identified a second species, Procambarus fallax (Hagen), from those locations. Reexamination of archived samples showed that P. fallax had been collected as early as 1985 but had been misidentified or overlooked; therefore, we provide...
We used time-activity budget techniques to measure foraging behavior of green-winged teal (Anas crecca carolinensis) and mallards (A. platyrhynchos). Observations were made on tidal mudflats in the Atchafalaya River Delta, Louisiana, USA, in the winter of 1994–1995. Green-winged teal spent more diurnal time than mallards foraging (68% vs. 35%). Time spent in different foraging postures also differed...
Wetland scientists and managers recognize the need to characterize hydrology for understanding wetland ecosystems. Hydrologic data, however, are not routinely collected in wetlands, in part because of a lack of knowledge about how to effectively measure hydrologic attributes and how frequently to measure water levels. To determine how measurement interval affects interpretation of water-level data,...
This experiment examined how elevation and control of early successional vegetation would affect the growth and survival of tree species used in restoration. Vegetation was controlled by either mowing or spraying with Accord [glyphosate,-(phosphononomethyl)glycine, in the form of its isopropylamine salt] herbicide. These control methods were applied to either the entire plot or a narrow 1-m strip...
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