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Ecosystems Restoration and Sustainability: Forest Ecosystems

Research

 

Duberstein, J.A., Conner, W.H., and Krauss, K.W., 2013, Woody vegetation communities of tidal freshwater swamps in South Carolina, Georgia and Florida (US) with comparisons to similar systems in the US and South America: Journal of Vegetation Science, http://dx.doi.org/10.1111/jvs.12115

An extensive survey of trees and shrubs was conducted to describe the communities from a range of tidal freshwater swamps. Four general communities were characterized and named according to the strongest individual indicator species in each: Water Tupelo (Nyssa aquatica) Community, Swamp Tupelo (Nyssa biflora) Community, Dwarf Palmetto (Sabal minor) Community and Cabbage Palm (Sabal palmetto) Community.

 

Duberstein, J.A., Krauss, K.W., Conner, W.H., Bridges, W.C. Jr., and Shelburne, V.B., 2013, Do Hummocks Provide a Physiological Advantage to Even the Most Flood Tolerant of Tidal Freshwater Trees?: Wetlands, v. 33, n. 3, p. 399-408, http://dx.doi.org/10.1007/s13157-013-0397-x

Hummock and hollow microtopography is pervasive in tidal freshwater swamps. Many tree species grow atop hummocks significantly more than in hollows, leading to the hypothesis that hummocks provide preferred locations for maximizing physiological proficiency of inhabiting trees that experience repeated flooding. We used thermal dissipation probes to measure the ecophysiological proficiency of a very flood-tolerant tree, Taxodium distichum, as manifested through in-situ changes in sapflow (a proxy for transpiration) in 11 trees on hummocks and 11 trees in hollows.

 

Noe, G.B., Krauss, K.W., Lockaby, B.G., Conner, W.H., Hupp, C.R., 2013, The effect of increasing salinity and forest mortality on soil nitrogen and phosphorus mineralization in tidal freshwater forested wetlands: Biogeochemistry, v. 114, n. 1-3, p. 225-244, http://dx.doi.org/10.1007/s10533-012-9805-1

Tidal freshwater wetlands are sensitive to sea level rise and increased salinity, although little information is known about the impact of salinification on nutrient biogeochemistry in tidal freshwater forested wetlands. We quantified soil nitrogen (N) and phosphorus (P) mineralization using seasonal in situ incubations of modified resin cores along spatial gradients of chronic salinification (from continuously freshwater tidal forest to salt impacted tidal forest to oligohaline marsh) and in hummocks and hollows of the continuously freshwater tidal forest along the blackwater Waccamaw River and alluvial Savannah River.

 

McCoy, J.W., Draugelis-Dale, R.O., Keeland, B.D., and Darville, R., 2010, A comparison of litter production in young and old baldcypress (Taxodium distichum L.) stands at Caddo Lake, Texas: Texas Journal of Science, v. 62, n. 1, p. 25-40, http://pubs.er.usgs.gov/publication/70038187

Aboveground primary productivity for cypress forests was assessed from measurements of litter production in two age groups and in two hydrological regimes (standing water and free-flowing). Caddo Lake, located in northeast Texas on the Texas-Louisiana border, offers a unique study site since it is dominated by extensive stands composed entirely of Taxodium distichum (L.) Rich. (baldcypress) in different age groups. Young stands (approximately 100 years old) are found along the shoreline and on shallow flooded islands. Old stands (~150 to 300 years old) are found in deeper water where they are continuously flooded.

 

Krauss, K.W., Doyle, T.W., and Howard, R.J., 2009, Is there evidence of adaptation to tidal flooding in saplings of baldcypress subjected to different salinity regimes?: Environmental and Experimental Botany, v. 67, n. 1, p. 118-126, http://dx.doi.org/10.1016/j.envexpbot.2009.05.005

Plant populations may adapt to environmental conditions over time by developing genetically based morphological or physiological characteristics. For tidal freshwater forested wetlands, we hypothesized that the conditions under which trees developed led to ecotypic difference in response of progeny to hydroperiod. Specifically, we looked for evidence of ecotypic adaptation for tidal flooding at different salinity regimes using growth and ecophysiological characteristics of two tidal and two non-tidal source collections of baldcypress (Taxodium distichum (L.) L.C. Rich) from the southeastern United States.

 

Krauss, K.W., Duberstein, J.A., Doyle, T.W., Conner, W.H., Day, R.H., Inabinette, L.W., and Whitbeck, J.L., 2009, Site condition, structure, and growth of baldcypress along tidal/non-tidal salinity gradients:
Wetlands, v. 29, n. 2, p. 505-519, http://dx.doi.org/10.1672/08-77.1

This report documents changes in forest structure and growth potential of dominant trees in salt-impacted tidal and non-tidal baldcypress wetlands of the southeastern United States. We inventoried basal area and tree height, and monitored incremental growth (in basal area) of co-dominant baldcypress (Taxodium distichum) trees monthly, for over four years, to examine the inter-relationships among growth, site fertility, and soil physico-chemical characteristics.

 

Lindquist, E.S., Krauss, K.W., Green, P.T., O’Dowd, D.J., Sherman, P.M., and Smith, T.J., 2009, Land crabs as key drivers in tropical coastal forest recruitment: Biological Reviews, v. 84, n. 2, p. 203-223, http://dx.doi.org/10.1111/j.1469-185X.2008.00070.x

Plant populations are regulated by a diverse assortment of abiotic and biotic factors that influence seed dispersal and viability, and seedling establishment and growth at the microsite. Rarely does one animal guild exert as significant an influence on different plant assemblages as land crabs. We review three tropical coastal ecosystems–mangroves, island maritime forests, and mainland coastal terrestrial forests–where land crabs directly influence forest composition by limiting tree establishment and recruitment. Land crabs differentially prey on seeds, propagules and seedlings along nutrient, chemical and physical environmental gradients.

 

Day, R.H., Williams, T.M., and Swarzenski, C.M., 2007, Hydrology of tidal freshwater forested wetlands of the Southeastern United States, IN, Conner, W.H., Doyle, T.W., and Krauss, K.W., eds., Ecology of Tidal Freshwater Forested Wetlands of the Southeastern United States: Springer, The Netherlands, p. 29-63, http://dx.doi.org/10.1007/978-1-4020-5095-4_2

The downstream, coastward boundary of tidal freshwater forests is easy to define. There is usually an abrupt border from forest to fresh, brackish, or salt marsh as tidal effect and salinity increase. Upstream, however, there is a continuum within the forested community as salinity and tidal signature diminish. The boundary conditions can be defined by salinity ranges, species distributions, or hydraulic relations. Unfortunately, each of these criteria leads to a different spatial and functional delineation of the tidal freshwater zone. We propose that tidal freshwater forested wetlands are coastal forested wetlands where the hydrology is affected by astronomical tides, and salinity does not normally exceed the tolerance of nonhalophytic tree species.

 

Krauss, K.W., Young, P.J., Chambers, J.L., Doyle, T.W., and Twilley, R.R., 2007, Sap flow characteristics of neotropical mangroves in flooded and drained soils: Tree Physiology, v. 27, n. 5, p. 775-783, http://dx.doi.org/10.1093/treephys/27.5.775

Effects of flooding on water transport in mangroves have previously been investigated in a few studies, most of which were conducted on seedlings in controlled settings. In this study, we used heat-dissipation sap probes to determine if sap flow attenuates with radial depth into the xylem of mature trees of three south Florida mangrove species growing in Rookery Bay.

 

Lockhart, B.R., Keeland, B., McCoy, J. and Dean, T.J., 2003, Comparing regeneration techniques for afforesting previously farmed bottomland hardwood sites in the Lower Mississippi Alluvial Valley, USA: Forestry, v. 76, n. 2, p. 169-180, http://dx.doi.org/10.1093/forestry/76.2.169

A study was implemented to test site preparation methods and artificial regeneration of three oak (Quercus spp.) species on four agricultural fields in the Lower Mississippi Alluvial Valley in Louisiana, USA. Successful bottomland hardwood afforestation projects require plans that include specific objectives, site evaluation, and a regeneration prescription prior to sowing the first seed or planting the first seedling.

 

Allen, J.A., Keeland, B.D., Stanturf, J.A., Clewell, A.F., and Kennedy, H.E., Jr., 2001 (revised 2004), A guide to bottomland hardwood restoration: U.S. Geological Survey, Biological Resources Division Information and Technology Report USGS/BRD/ITR–2000-0011, U.S. Department of Agriculture, Forest Service, Southern Research Station, General Technical Report SRS–40, 132 p., http://www.srs.fs.usda.gov/pubs/gtr/gtr_srs040.pdf

During the last century, a large amount of the original bottomland hardwood forest area in the United States has been lost, with losses greatest in the Lower Mississippi Alluvial Valley and East Texas. With a holistic approach in mind, this manual describes methods to restore bottomland hardwoods in the lower Midwest, including the Lower Mississippi Alluvial Valley and the southeastern United States.


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