Vegetation ecology of tidal freshwater swamps of the lower Chesapeake Bay, United States of America

Woody and herbaceous vegetation were sampled in 23 tidal swamps along a tidal freshwater tributary of lower Chesapeake Bay. Four vegetative categories were ordinated with Detrended Correspondence Analysis (DECORANA). Species distribution patterns of each strata were compared with respect to edaphic factors, a wetness index, and mean water table depth. Woody species are restricted to hummocks (topographic highs). Hummocks drain as quickly as the tide drops and so are partially inundated for only short periods each day. Although low in canopy diversity, tidal swamps are floristically rich in herbaceous and woody understory species, ranking them among the most speciose in temperate North America. Canopy composition is related to the wetness of a site as determined by the percent of the forest floor covered by hollows (low inter-hummock depressions) and by mean water table depth. Fraxinus spp. and Nyssa biflora dominated swamps are best developed in wetter sites, which contain higher calcium (Ca) and organic matter (Om) levels and where the mean water table depth is about &-&17 cm. In contrast, Acer rubrum-Liquidambar styraciflua-Nyssa biflora dominated swamps occur at less wet sites where mean water table depth is deeper than 20 cm. Although DECORANA separated canopy and herbaceous strata similarly, the woody subcanopy (shrubs and small understory tree species) did not separate into the same two communities. to determine whether this pattern might be indicative of forests in general, distributional data of canopy and subcanopy species were also compared using similarly collected data from a southern Appalachian forest. Sapling (juvenile canopy species) distribution patterns were also compared in both systems. Separate ordinations were performed on canopy, sapling, and subcanopy species. Canopy trees and saplings showed a similar pattern of distribution, suggesting that resource requirements of saplings and canopy-statured adults are similar. In contrast, the subcanopy species of neither ecosystem showed any discernable distributional relationship to the canopy or sapling layers, suggesting that subcanopy life-forms may partition different resources than canopy species in temperate forests. If so, the common practise of combining sapling and subcanopy species in structural analyses may hinder our understanding of subcanopy structural patterns in forests

Carbon storage of headwater riparian zones in an agricultural landscape

<p>Abstract</p> <p>Background</p> <p>In agricultural regions, streamside forests have been reduced in age and extent, or removed entirely to maximize arable cropland. Restoring and reforesting such riparian zones to mature forest, particularly along headwater streams (which constitute 90% of stream network length) would both increase carbon storage and improve water quality. Age and management-related cover/condition classes of headwater stream networks can be used to rapidly inventory carbon storage and sequestration potential if carbon storage capacity of conditions classes and their relative distribution on the landscape are known.</p> <p>Results</p> <p>Based on the distribution of riparian zone cover/condition classes in sampled headwater reaches, current and potential carbon storage was extrapolated to the remainder of the North Carolina Coastal Plain stream network. Carbon stored in headwater riparian reaches is only about 40% of its potential capacity, based on 242 MgC/ha stored in sampled mature riparian forest (forest > 50 y old). The carbon deficit along 57,700 km headwater Coastal Plain streams is equivalent to about 25TgC in 30-m-wide riparian buffer zones and 50 TgC in 60-m-wide buffer zones.</p> <p>Conclusions</p> <p>Estimating carbon storage in recognizable age-and cover-related condition classes provides a rapid way to better inventory current carbon storage, estimate storage capacity, and calculate the potential for additional storage. In light of the particular importance of buffer zones in headwater reaches in agricultural landscapes in ameliorating nutrient and sediment input to streams, encouraging the restoration of riparian zones to mature forest along headwater reaches worldwide has the potential to not only improve water quality, but also simultaneously reduce atmospheric CO₂.</p

Feral horse seasonal habitat use on a coastal barrier spit

Management of feral horses grazing on Atlantic and Gulf coast barrier islands requires information on seasonal habitat preferences and distribution of important forage species to maintain stable populations and prevent destruction of fragile island ecosystems, particularly as coastal development further restricts free range. Counts from seasonal aerial surveys of Currituck Banks, N.C. were used to determine whether particular habitats were used more or less than would be expected by chance. On-ground observations were used to determine the relative intensity of grazing on vegetation by habitat and season. Feral horses showed seasonal preferences for particular forage species and habitat types. Horses grazed upon at least 16 graminoid and 5 forb species across 6 identified habitat types covering 4,619 ha. In late winter, Maritime Forest was used significantly more than expected while Tidal Freshwater Marsh was used less than expected. In spring, all habitats were used in the proportion expected based on availability. In early summer, Wet Grassland was preferentially used while Dry Grassland was preferentially avoided. The relative degree of exposure from wind may explain why horses spent less time than expected in exposed marshes during winter and more time than expected in forest. The availability of fresh water and hydrophytes may explain why horses spent more time than expected in Wet Grassland in summer and less time than expected in Dry Grassland. Seasonal habitat preferences should be considered when managing for ecosystem sustainability of feral horses on barrier islands.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

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this report was authorized by Headquarters, U.S. Army Corps of Engineers (HQUSACE), as part of the Delineation and Evaluation Task Area of the Wetlands Research Program (WRP). The work was performed under Work Unit 32756, &quot;Evaluation of Wetland Functions and Values,&quot; for which Mr. R. Daniel Smith, Environmental Laboratory (EL), U.S. Army Engineer Waterways Experiment Station (WES), was the Principal Investigator. Mr. John Bellinger (CECW-PO) was the WRP Technical Monitor for this work. Development funds were also contributed by the institutions, agencies, and firms with which the authors are associated (the Environmental Protection Agency (3-BO978NTEX) and the Divisions of Coastal Management (F3078) and Environmental Management (J-3054) of the North Carolina Department of Environment, Health, and Natural Resources), as well as other sources of funds and support. Mr. Dave Mathis (CERD-C) was the WRP Coordinator at the Directorate of Research and Development, HQUSACE; Dr. William L. Klesch (CECW-PO) served as the WRP Technical Monitor&apos;s Representative; Dr. Russell F. Theriot, WES, was the Wetlands Program Manager; and Mr. Ellis J. Clairain, WES, was the Task Area Manager. The work was performed under the direct supervision of Mr. Smith and under the general supervision of Mr. Clairain, Acting Chief, Wetlands Branch; Dr. Conrad J. Kirby, Chief, Ecological Research Division; and Dr. John W. Keeley, Director, EL. This report was prepared by Dr. Mark M. Brinson, professor, Biology Department, and Dr. Richard D. Rheinhardt, research assistant, East Carolina University, Greenville, NC; Dr. F. Richard Hauer, professor, Flathead Lake Biological Station, University of Montana, Polson, MT; Dr. Lyndon C. Lee, L. C. Lee and Associates, Inc., Seattle, WA; Dr. Wade L. Nutter, hydrologi..