Topic
Pocosin
About: Pocosin is a research topic. Over the lifetime, 72 publications have been published within this topic receiving 1655 citations.
Papers published on a yearly basis
Papers
TL;DR: In this paper, the authors examined factors controlling aerobic and anaerobic soil respiration in three contrasting types of freshwater North Carolina peatland communities (short pocosins, tall poccosins and gum swamps) which occur along a natural soil nutrient availability gradient.
Abstract: Production of soil gases is important in nutrient and carbon cycling, particularly in peatlands due to their large atmospheric emissions of several greenhouse gases. We examined factors controlling aerobic and anaerobic soil respiration in three contrasting types of freshwater North Carolina peatland communities (short pocosins, tall pocosins and gum swamps) which occur along a natural soil nutrient availability gradient. Short pocosins occur in the ombrotrophic center of the bog complexes and are extremely nutrient-deficient; tall pocosins are slightly less nutrient-deficient; and gum swamps are relatively nutrient-rich. Short pocosin had the lowest soil CO 2 production rates under both aerobic and anaerobic conditions in laboratory experiments, while rates in tall pocosin were similar to or somewhat less than in the gum swamp. Methanogenesis rates were extremely low in laboratory experiments, and indicate that CH 4 production is not a significant pathway of carbon flow in these peatlands. Methane production is also low in relation to other peatlands. Amendment experiments indicate that the poor substrate quality of the highly decomposed, humified peat limits both CO 2 and CH 4 production rates, even though the peat is 95% organic matter. Low soil nutrient concentrations and low pH do not directly limit soil respiration in these peatlands, although there is a positive feedback of nutrients with organic matter inputs and litter quality, causing greater soil respiration in nutrient-rich sites. In situ CO 2 emissions similarly differed between the communities, with highest rates in the gum swamp and lowest rates in the pocosins. Emissions were highly seasonal with soil temperature explaining the majority of the temporal variability. Maximum potential CH 4 emission estimates derived from laboratory temperature relationships and in situ soil temperature data indicate that pocosins make an insignificant contribution to the global atmospheric CH 4 flux. The continued existence of peatlands in warm climates may to a large extent depend on the low substrate quality of their soil organic matter, which maintains low decomposition rates under both aerobic and anaerobic conditions.
296 citations
1 Nov 1982
TL;DR: Pocosins and Carolina bays as mentioned in this paper are types or subclasses of shrub bogs on the coastal plains of the Carolinas and Georgia and share roughly the same distribution patterns, soil types, floral and faunal species composition and other community attributes, but differ in geological formation.
Abstract: Shrub bogs of the Southeast occur in areas of poorly developed internal drainage that typically but not always have highly developed organic or peat soils. Pocosins and Carolina bays are types or subclasses of shrub bogs on the coastal plains of the Carolinas and Georgia. They share roughly the same distribution patterns, soil types, floral and faunal species composition and other community attributes, but differ in geological formation. Carolina bays may contain pocosin as well as other communities, but are defined more by their unique elliptical shape and geomorphometry. The pocosin community is largely defined by its vegetation, a combination of a dense shrub understory and a sparser canopy. The community is part of a complex successional sequence of communities (sedge bogs, savannas, cedar bogs, and bay forests) that may be controlled by such factors as fire, hydroperiod, soil type, and peat depth. Pocosins and Carolina bays harbor a number of animal groups and may be locally important in their ecology. Although few species are endemic to these habitats, they may provide important refuges for a number of species. These communities are simultaneously among the least understood and most rapidly disappearing habitats of the Southeast. Forestry and agricultural clearage aremore » current impacts.« less
159 citations
TL;DR: In this paper, the authors compared hydrology, soils, and water quality of an agricultural field (AG), a two-year-old restored wetland (RW), and two reference ecosystems (a non-riverine swamp forest (NRSF) and a high pocosin forest (POC)) located at the Barra Farms Regional Wetland Mitigation Bank, a Carolina bay complex in Cumberland County, North Carolina.
Abstract: We compared hydrology, soils, and water quality of an agricultural field (AG), a two-year-old restored wetland (RW), and two reference ecosystems (a non-riverine swamp forest (NRSF) and a high pocosin forest (POC)) located at the Barra Farms Regional Wetland Mitigation Bank, a Carolina bay complex in Cumberland County, North Carolina. Our main objectives were to: 1) determine if the RW exhibited hydrology comparable to a reference ecosystem, 2) characterize the soils of the AG, RW, and reference ecosystems, and 3) assess differences in water quality in the surface outflow from the AG, RW, and reference ecosystems. Water table data indicated that the hydrology of the RW has been successfully reestablished as the hydroperiod of the RW closely matched that of the NRSF in 1998 and 1999. Jurisdictional hydrologic success criterion was also met by the RW in both years. To characterize soil properties, soil cores from each ecosystem were analyzed for bulk density (Db), total carbon (Ct), nitrogen (Nt), and phosphorus (Pt), extractable phosphate (PO4w), nitrogen (Nex), and cations (Caex, Mgex, Kex, Naex), as well as pH. Bulk density, Pt, Caex, Mgex, and pH were greatly elevated in the AG and RW compared to the reference ecosystems. Water quality monitoring consisted of measuring soluble reactive phosphorus (SRP), total phosphorus (TP), nitrate + nitrite (NOX), and total nitrogen (TN) concentrations in surface water from the AG, RW, and reference outflows. Outflow concentrations of SRP, TP, and NOX were highest and most variable in the AG, while TN was highest in the reference. This study suggested that while restoration of wetland hydrology has been successful in the short term, alteration of wetland soil properties by agriculture was so intense, that changes due to restoration were not apparent for most soil parameters. Restoration also appeared to provide water quality benefits, as outflow concentrations of SRP, TP, NOX, and TN were lower in the RW than the AG.
101 citations
TL;DR: The results indicate that relative bark thickness is likely the primary bark trait affecting fire-induced topkill and influencing the distribution of species along the pocosin-to-savanna gradient.
Abstract: The probability of stem survival after fire is strongly influenced by energy allocation to bark because bark thickness affects heat transfer during fire. Greater relative investment in inner bark versus outer bark should also enhance survival because of greater moisture content of inner bark. We measured stem diameter, bark thickness, and habitat preference of five species typical of long-leaf pine savannas, and six species characteristic of adjacent wetlands (pocosins), and calculated relative bark thickness, the inner bark proportion, radial growth, and bark accumulation of each species. We hypothesized that savanna species have thicker bark and greater relative investment in inner bark than pocosin species, because fires occur more frequently in savannas than pocosins. As hypothesized, savanna species have relatively thicker bark than pocosin species. Relative bark thickness and the rate of bark accumulation were correlated with the mean location of a species along the pocosin-to-savanna gradient. However, the inner bark proportion did not differ between savanna and pocosin species. Our results indicate that relative bark thickness is likely the primary bark trait affecting fire-induced topkill and influencing the distribution of species along the pocosin-to-savanna gradient.
70 citations
TL;DR: In this article, the effects of land development activities on hydrologic fluxes in peatlands (Typic Medisaprists) were compared to the effect of forest management practices in North Carolina using a field-tested hydrological simulation model (DRAINMOD), which revealed that natural peat-based pocosin systems lose 66% of the 123 cm of average annual rainfall by evapo-transpiration (ET) and 34% (42 cm/yr) via annual runoff.
Abstract: Land development activities such as agriculture, clear cutting, peat mining, and the planting of forest plantations on wetlands can affect the hydrologic behavior of these ecosystems by affecting their water storage and release patterns on the landscape. The effects of these development activities on hydrologic fluxes in peatlands (Typic Medisaprists) were compared to the effects of forest management practices in North Carolina using a field-tested hydrologic simulation model (DRAINMOD). Simulations revealed that natural peat-based (Histosol) pocosin systems lose 66% (80 cm) of the 123 cm of average annual rainfall by evapo-transpiration (ET) and 34% (42 cm/yr) via annual runoff. Annual runoff values were 63 cm/yr for peat mining areas, 48 cm/yr for cleared peatlands, 46 cm/yr for peatlands converted to agriculture and 34 cm/yr for pine plantations, once the forest canopy is closed. Thus, these wetland alterations, except for forestry, significantly increased runoff and decreased ET compared to the natural ecosystem. Forest pine plantation management decreased runoff and increased ET. A case study of the effects of forest management practices was reviewed for a 15-year-old drained loblolly pine plantation growing on fine sandy loam soils (Thermic Typic umbraquults) in the coastal plains of North Carolina. Forestry activities such as thinning (i.e., reduced leaf area index by 50%) decreased ET and canopy interception and nearly doubled drainage loss (38 cm/yr to 60 cm/yr). Commonly applied forest practices, such as drainage, increased the average number of flow events with flows > 5 mm/day to 86 days per year from 26 days per year under natural conditions.
58 citations
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