Wetlands

Wilcox, Douglas

doi: 10.1007/BF03160828pmid: N/A

Wood, John; Tanner, George

doi: 10.1007/BF03160829pmid: N/A

Estimates of species density, percentage vegetative cover, biomass, and sawgrass (Cladium jamaicense) height were made in Tall Sawgrass, Medium Sawgrass, and Wet Prairie communities in the SE portion of Water Conservation Area 3A (3A), the SW portion of Water Conservation Area 3B (3B), the NW portion of Northeast Shark Slough (NSS), and the NE portion of Everglades National Park (ENP) during dry season and wet season sampling periods in 1986 and 1987. We summarized the history of water management and hydroperiod manipulation in the study area. Wet Prairie had the deepest water of the three plant communities studied, while 3A had deepest water and longest hydroperiod of the four areas. Generally, the greatest species density occurred in NSS, where water was shallowest. Individual sawgrass plants and their basal tussocks were taller in 3A than in the other three areas, which may make plants in 3A more susceptible to damage by airboats and fire. Cover and biomass of sawgrass fluctuated more between sampling periods than among management areas, which rendered lower measurements in Tall Sawgrass in 3B non-significant. Species composition of Wet Prairies, particularly in 3A whereRhynchospora spp. were absent, andNymphaea odorata was dominant, resembled aquatic sloughs. The low species density in the study area may be related to rapid fluctuations in water levels that could drown slow-growing plants, and to infrequent dry periods that preclude seed germination. Species richness was low, compared with other Everglades plant community studies. No annual emergent plants were encountered.

Rey, Jorge; Shaffer, John; Crossman, Roy; Tremain, Derek

doi: 10.1007/BF03160830pmid: N/A

Yearly above-ground production estimates in natural, ditched, and impounded high salt marshes along the Indian River Lagoon in east central Florida ranged from 834.9 g/m2 in the impounded marsh to 2.316.5 g/m2 in the natural one. Mosquito control activities in the impounded marsh prior to the start of this study resulted in larger stocks of dead and litter biomass there during the first year than at the other two marshes. High soil temperature and salinity during the summer may have caused a decrease in production during that season. Annual tumover rales varied from 5.8 at the impounded marsh during the first year to 1.1 at the impounded marsh and at a nearby ditched marsh during the second year. Prduction was inversely correlated with flooding frequency. No significant differences were found in the rates of litter loss from any of the sites, but litter from the impounded marsh had greater organic content than litter from the open and the ditched marshes. The data suggest that flooding for mosquito control during the summer can curtail production, but the effects upon yearly production are minor, as production during the summer is naturally low.

Riley, Terry; Bookhout, Theodore

doi: 10.1007/BF03160831pmid: N/A

Effects of early-spring water-level reduction on aquatic macroinvertebrate populations were studied in four nodding smartweed (Polygonum lapathifolium L.) marshes in northwest Ohio. Water depths in two marshes were maintained at normal (>40 cm) overwinter levels then were reduced in early April each year to approximately 50% (20 cm) of over-winter depth. Water levels in two other marshes were allowed to fluctuate naturally throughout the study period.

Whitehead, John

doi: 10.1007/BF03160832pmid: N/A

Preservation of bottomland hardwood forest wetlands is threatened by pressure from surface coal mining activities in the western Kentucky coalfield. The contingent valuation, survey method was used to measure the economic benefits (willingness-to-pay) of preserving the Clear Creek wetland, the largest wetland area in the coalfield, from surface coal mining. Results indicated that Kentucky households are willing to pay between $6 and $13, in the form of voluntary contributions to a hypothetical “Wetland Preservation Fund,” for preservation. Mine reclamation as a substitute for preservation recreational use of wetlands by survey respondents, conservation club membership, and age are determinants of willingness-to-pay. Annual aggregate benefits of Clear Creek wetland preservation are estimated to be between $2.94 million and $19 million depending on aggregation assumptions.

McGovern, John; Wenner, Charles

doi: 10.1007/BF03160833pmid: N/A

Seasonal recruitment of larval and juvenile fishes into impounded and nonimpounded marshes in South Carolina was investigated from January 1983 to January 1984 (Year I) and from February 1984 to December 1984 (Year II). A total of 53,230 fishes representing over 29 families and at least 64 species was collected. The most numerous species, spot (Leiostomus xanthurus), comprised 55% of the total catch. Samples from creek stations (Years I and II) and an impoundment station (Year II) showed seasonal changes in diversity and species richness. These seasonal changes were probably due to the transient nature of the numerically dominant fishes. Year I impoundment samples did not show these seasonal fluctuations. A single peak in both the numbers of individuals and species in ichthyoplankton collections at the impoundments occurred in May 1983 *Year I) when tidal exchange was at a maximum. Otherwise, few fishes were collected at impoundment stations in Year I when flow rates through the water control structures were reduced. Thus, many species that normally would have used this marsh area as a nursery were denied access because trunks were closed when these species were abundant in the creeks.

Breininger, David; Smith, Rebecca

doi: 10.1007/BF03160834pmid: N/A

Monthly surveys were conducted on Kennedy Space Center for one year to determine densities of waterbirds within impounded salt marshes that were predominantly open water with little emergent vegetation. The objective was to assess the importance of these impoundments to waterbirds, particularly wading birds, which are species of special conservation concern. Water-level management for mosquito control and waterfowl provided habitat for an abundance of ducks, shorebirds, coots, and wading birds. Average densities throughout the year for these groups were 5.26, 4.12, 2.80, and 2.20 birds/ha, respectively. The majority of waterfowl were present during the winter. Shorebirds were most common during spring migration. Wading bird densities increased with declining water level. Due to the extensive alteration and development of coastal wetlands in central Florida, properly managed impoundments may provide important feeding areas for maintaining certain waterbird populations.

Wrubleski, Dale; Rosenberg, David

doi: 10.1007/BF03160835pmid: N/A

Adult midge flies, Chironomidae, were collected by emergence traps from a shallow, semi-isolated bay of the Delta Marsh, Manitoba, over a two-year period. Three habitats were sampled—sago pondweed (Potamogeton pectinatus), hybrid cattail (Typha ×glauca), and hardstem bulrush (Scirpus acutus). The pondweed habitat was the most productive of the three habitats sampled, both in terms of numbers and biomass of emerging chironomids. Eighty-four species were collected, the most abundant beingTanypus punctipennis, Psectrotanypus alaskensis, Cricotopus sylvestris, Corynoneuracf. scutellata, Limnophyes prolongatus, L. immucronatus, Glyptotendipes barbipes, G. lobiferus, Chironomus tentans. Dicrotendipes nervosus, Paratanytarsus sp. 1, andCladotanytarsus sp. Most of the dominant species were bi- or multivoltine, but considerable inter-annual variation was noted in emergence rates and patterns.

Larson, John; Stearns, Forest

doi: 10.1007/BF03160836pmid: N/A

Carex scoparia seeds collected in 1985, 1987, and 1988 in a southeastern Wisconsin sedge meadow were used to investigate appropriate storage conditions and the influence of two alternating temperature regimes on germination. Seeds collected in 1987 and 1988 stored dry at room temperature (dry-warm) had a higher germination at both 21/25 C and 25/32 C than seed of the same age that was stored dry in a refrigerator (dry-cool). Seeds collected in 1985, over two years old, gave a higher percentage germination when stored drycool than dry-warm seed of the same age.