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Claudia I. Mora - One of the best experts on this subject based on the ideXlab platform.

  • Sensitivity of bulk sedimentary stable carbon isotopes to prehistoric Forest Clearance and maize agriculture
    Journal of Archaeological Science, 2008
    Co-Authors: Chad S. Lane, Sally P. Horn, Claudia I. Mora, Kenneth H. Orvis
    Abstract:

    The stable carbon isotope compositions (d 13 C) of tropical lake sediments and soils have been used to reconstruct the occurrence of prehistoric maize cultivation and its relative importance through time. This study assesses some of the possible variables affecting the response of lake sediment bulk organic carbon isotope (d 13 CTOC) values to variations in the scale of prehistoric maize cultivation and the potential of this proxy to yield quantitative estimates of the scale of prehistoric maize agriculture in small tropical watersheds. High resolution analyses of d 13 CTOC values, maize pollen concentrations, and mineral influx were conducted on sediments deposited during a w220 year period of prehistoric maize agriculture in the watershed of Laguna Castilla, a small lake in the mid-elevations of the Cordillera Central, Dominican Republic. Close correspondence between d 13 CTOC values and maize pollen concentrations in the Laguna Castilla sediment record indicates a close relationship between the isotopic values and the scale of prehistoric maize cultivation. Correlations between the d 13 CTOC signature and mineral influx indicate that the isotope record is also sensitive to variations in allochthonous carbon delivery. This study establishes that sedimentary d 13 CTOC values can provide a highly sensitive proxy of the spatial scale of prehistoric maize agriculture in small tropical watersheds, but

  • Stable carbon isotope ratios in lake and swamp sediments as a proxy for prehistoric Forest Clearance and crop cultivation in the Neotropics
    Journal of Paleolimnology, 2004
    Co-Authors: Chad S. Lane, Sally P. Horn, Claudia I. Mora
    Abstract:

    Close correspondence between stable carbon isotope ratios (δ 13 C), pollen, and charcoal profiles in sediment cores from Laguna Zoncho and Machita swamp, Costa Rica, shows that prehistoric Forest Clearance and crop cultivation can be detected in the stable carbon isotope ratios of total organic carbon (δ 13C TOC ). Analyses of I´ 13C TOC complement evidence from pollen, charcoal, and phytoliths and provide a proxy that is sensitive to the intensity and/or proximity to core sites of prehistoric Forest Clearance and agriculture in watersheds. Stable carbon isotope analyses are particularly useful in situations in which other evidence of Forest Clearance and agriculture is limited.

Chad S. Lane - One of the best experts on this subject based on the ideXlab platform.

  • Sensitivity of bulk sedimentary stable carbon isotopes to prehistoric Forest Clearance and maize agriculture
    Journal of Archaeological Science, 2008
    Co-Authors: Chad S. Lane, Sally P. Horn, Claudia I. Mora, Kenneth H. Orvis
    Abstract:

    The stable carbon isotope compositions (d 13 C) of tropical lake sediments and soils have been used to reconstruct the occurrence of prehistoric maize cultivation and its relative importance through time. This study assesses some of the possible variables affecting the response of lake sediment bulk organic carbon isotope (d 13 CTOC) values to variations in the scale of prehistoric maize cultivation and the potential of this proxy to yield quantitative estimates of the scale of prehistoric maize agriculture in small tropical watersheds. High resolution analyses of d 13 CTOC values, maize pollen concentrations, and mineral influx were conducted on sediments deposited during a w220 year period of prehistoric maize agriculture in the watershed of Laguna Castilla, a small lake in the mid-elevations of the Cordillera Central, Dominican Republic. Close correspondence between d 13 CTOC values and maize pollen concentrations in the Laguna Castilla sediment record indicates a close relationship between the isotopic values and the scale of prehistoric maize cultivation. Correlations between the d 13 CTOC signature and mineral influx indicate that the isotope record is also sensitive to variations in allochthonous carbon delivery. This study establishes that sedimentary d 13 CTOC values can provide a highly sensitive proxy of the spatial scale of prehistoric maize agriculture in small tropical watersheds, but

  • Stable carbon isotope ratios in lake and swamp sediments as a proxy for prehistoric Forest Clearance and crop cultivation in the Neotropics
    Journal of Paleolimnology, 2004
    Co-Authors: Chad S. Lane, Sally P. Horn, Claudia I. Mora
    Abstract:

    Close correspondence between stable carbon isotope ratios (δ 13 C), pollen, and charcoal profiles in sediment cores from Laguna Zoncho and Machita swamp, Costa Rica, shows that prehistoric Forest Clearance and crop cultivation can be detected in the stable carbon isotope ratios of total organic carbon (δ 13C TOC ). Analyses of I´ 13C TOC complement evidence from pollen, charcoal, and phytoliths and provide a proxy that is sensitive to the intensity and/or proximity to core sites of prehistoric Forest Clearance and agriculture in watersheds. Stable carbon isotope analyses are particularly useful in situations in which other evidence of Forest Clearance and agriculture is limited.

Sally P. Horn - One of the best experts on this subject based on the ideXlab platform.

  • Sensitivity of bulk sedimentary stable carbon isotopes to prehistoric Forest Clearance and maize agriculture
    Journal of Archaeological Science, 2008
    Co-Authors: Chad S. Lane, Sally P. Horn, Claudia I. Mora, Kenneth H. Orvis
    Abstract:

    The stable carbon isotope compositions (d 13 C) of tropical lake sediments and soils have been used to reconstruct the occurrence of prehistoric maize cultivation and its relative importance through time. This study assesses some of the possible variables affecting the response of lake sediment bulk organic carbon isotope (d 13 CTOC) values to variations in the scale of prehistoric maize cultivation and the potential of this proxy to yield quantitative estimates of the scale of prehistoric maize agriculture in small tropical watersheds. High resolution analyses of d 13 CTOC values, maize pollen concentrations, and mineral influx were conducted on sediments deposited during a w220 year period of prehistoric maize agriculture in the watershed of Laguna Castilla, a small lake in the mid-elevations of the Cordillera Central, Dominican Republic. Close correspondence between d 13 CTOC values and maize pollen concentrations in the Laguna Castilla sediment record indicates a close relationship between the isotopic values and the scale of prehistoric maize cultivation. Correlations between the d 13 CTOC signature and mineral influx indicate that the isotope record is also sensitive to variations in allochthonous carbon delivery. This study establishes that sedimentary d 13 CTOC values can provide a highly sensitive proxy of the spatial scale of prehistoric maize agriculture in small tropical watersheds, but

  • Stable carbon isotope ratios in lake and swamp sediments as a proxy for prehistoric Forest Clearance and crop cultivation in the Neotropics
    Journal of Paleolimnology, 2004
    Co-Authors: Chad S. Lane, Sally P. Horn, Claudia I. Mora
    Abstract:

    Close correspondence between stable carbon isotope ratios (δ 13 C), pollen, and charcoal profiles in sediment cores from Laguna Zoncho and Machita swamp, Costa Rica, shows that prehistoric Forest Clearance and crop cultivation can be detected in the stable carbon isotope ratios of total organic carbon (δ 13C TOC ). Analyses of I´ 13C TOC complement evidence from pollen, charcoal, and phytoliths and provide a proxy that is sensitive to the intensity and/or proximity to core sites of prehistoric Forest Clearance and agriculture in watersheds. Stable carbon isotope analyses are particularly useful in situations in which other evidence of Forest Clearance and agriculture is limited.

P.a. Stevens - One of the best experts on this subject based on the ideXlab platform.

  • Soil fertility under Calliandra calothyrsus hedgerows and other land-use treatments following Forest Clearance in Jamaica
    Agroforestry Systems, 2003
    Co-Authors: Morag A. Mcdonald, P.a. Stevens, John R. Healey
    Abstract:

    An experiment in the Blue Mountains of Jamaica investigated the consequences of three land-use treatments applied following Forest Clearance on soil fertility and resulting crop growth over a five year period. The treatments were: maintained weed-free without cultivation (bare); cultivated with herbaceous crops (agriculture); and cultivated with herbaceous crops and intercropped with Calliandra calothyrsus contour hedges (agroForestry) and compared with an uncleared secondary Forest control (Forest). Nitrogen mineralisation rates declined over time since Forest Clearance in the cleared treatments, but not in the Forest. In the second and third years after Clearance nitrogen mineralisation was higher under the hedgerows than all other treatments. However, by the fifth year this had reduced to net immobilization (both under and between hedgerows). Under controlled shade-house conditions bioassay plant growth was similar in soil from agricultural plots and from Forest plots. In all the soils bioassay plant growth showed a slight (not significant) positive response to P addition. However, it did show a large positive response to N addition in all soils: most for agriculture soils, least for Forest soils and intermediate for agroForestry. Crop plants growing in the agroForestry plots had significantly higher growth than those in the agriculture plots. This was sufficient to lead to grain yield per hectare being only 5% lower in agroForestry plots despite there being c. 20% fewer maize plants per hectare than in the agriculture plots. However, the results suggest that there was no clear positive effect of C. calothyrsus on soil fertility five years after establishment.

  • The effects of secondary Forest Clearance and subsequent land-use on erosion losses and soil properties in the Blue Mountains of Jamaica
    Agriculture Ecosystems & Environment, 2002
    Co-Authors: Morag A. Mcdonald, John R. Healey, P.a. Stevens
    Abstract:

    As pressure on land and Forest resources increases, there is a growing need to assess and improve the sustainability of slash-and-burn agriculture in tropical uplands. On steep-hillslopes (24–32 ◦ ) in the Forest buffer zone of the Blue Mountains of Jamaica, following Clearance of secondary Forest the relative impact on surface runoff, soil erosion and soil properties of three land-use treatments: maintained weed-free without cultivation (bare); cultivated with herbaceous crops (agriculture); and cultivated with herbaceous crops and intercropped with Calliandra calothyrsuscontour hedges (agroForestry) was assessed over a 5-year period and compared with an uncleared secondary Forest control (Forest). The Forest provided good protection against surface runoff (which was consistently less than 0.2% of rainfall) and soil erosion losses (less than 500 kg ha −1 per year); agriculture caused a seven-fold increase in surface runoff and 21-fold increase in soil erosion. However, agroForestry was effective in conservation of water (45% reduction in runoff compared with agriculture) and soil (erosion reduced by 35%). The Clearance of the secondary Forest led to large changes in most measured soil properties. Over 5 years concentrations of organic matter declined by 31%, total N by 38%, exchangeable K by 47%, Ca by 43% and Mg by 56%; over the same period bulk density increased by 48%. Of the soil properties more subject to year-to-year fluctuations, after 5 years the concentration of available P was 36% less in cleared plots than in Forest, exchangeable Na was 50% less and moisture content 43% less. Only total P concentration and pH were unaffected. Five years after Forest Clearance there was no good evidence that these changes had stabilised and very little difference in soil properties was found amongst the three land-use treatments. However, within the agroForestry plots, exchangeable K, Na and sand concentrations became higher under the hedgerows than between them (by 14, 9 and 8%, respectively), whilst clay concentration became higher between them (by 9%). The results indicate that this low-input, contour-tree-hedgerow technology is effective at soil and water conservation through the sieve-barrier effect and increased water infiltration (respectively) and has the potential to enhance the sustainability of this land-use system at a plot scale. © 2002 Elsevier Science B.V. All rights reserved.

P. L. Marks - One of the best experts on this subject based on the ideXlab platform.

  • Environmental causes and consequences of Forest Clearance and agricultural abandonment in central New York, USA
    Journal of Biogeography, 2005
    Co-Authors: Kathryn M. Flinn, Mark Vellend, P. L. Marks
    Abstract:

    Aim Climate, topography and soils drive many patterns of plant distribution and abundance across landscapes, but current plant communities may also reflect a legacy of past disturbance such as agricultural land use. To assess the relative influences of environmental conditions and disturbance history on vegetation, it is important to understand how these forces interact. This study relates the geographical distribution of land uses to variation in topography and soils; evaluates the consequences of land-use decisions for current Forests; and examines the effects of agricultural land use on the chemical properties of Forest soils. Location Tompkins County occupies 1250 km 2 in central New York’s Finger Lakes region. Like much of eastern North America, this area underwent Forest Clearance for agriculture during the 1800s and widespread field abandonment and Forest recovery during the 1900s. The current landscape consists of a patchwork of Forests that were never cleared, Forests that developed on old fields and active agricultural lands.