Résultats de la recherche | Land Portal

Résultats de la recherche

Showing items 1 through 9 of 55.
  1. Library Resource
    Articles et Livres
    décembre, 2013
    États-Unis d'Amérique

    Despite numerous ecosystem services provided by urban trees, they are continually threatened by combined natural disturbances, invasive species, development and negligent management practices. This research characterizes the amount and cause of tree loss in Worcester, Massachusetts, in the northeast United States, and neighbouring towns between 2008 and 2010 using multi-source remotely sensed imagery and historical land cover maps (1976–2009).

  2. Library Resource
    Articles et Livres
    décembre, 2013
    États-Unis d'Amérique

    Lidar and orthophotograph-derived land cover are combined with in situ vegetation measurements to assess habitat characteristics typifying four species of butterflies with differing habitat preferences across a large spatial extent (∼30,000 ha) in northern Idaho, USA. Lidar data are employed to characterize both vegetation structure and topography, whereas digital orthophotographs and in situ vegetation measurements are employed to quantify surrounding land use and larval host plant cover, respectively.

  3. Library Resource
    Articles et Livres
    décembre, 2011
    Groenland, Antarctique

    In this study, a terrain classification algorithm is presented that was derived from various properties of the returned full waveform signals collected from the Ice, Cloud and land elevation Satellite (ICESat) mission. Such an algorithm would be beneficial for current and future studies of the cryosphere, particularly Greenland and Antarctica, by helping to identify changes in the large scale surface properties over time. The algorithm developed was validated over a test region in the Dry Valleys of Antarctica, where the terrain is well known and regularly monitored.

  4. Library Resource
    Articles et Livres
    décembre, 2013
    États-Unis d'Amérique

    Removing excess biomass from fire-hazardous forests can serve dual purposes: enhancing the health and sustainability of forest ecosystems and supplying feedstock for energy production. The physical availability of this biomass is fairly well-known, yet availability does not necessarily translate into actual supply. We assess the perception and behavior of private forestland owners in the southern United States with respect to thinning overstocked forests for bioenergy production.

  5. Library Resource
    Articles et Livres
    décembre, 2013
    États-Unis d'Amérique

    Water rights markets in the western United States have expanded over the last 40 years, as a result of population growth in the West and Southwest, and limited development of new storage. Until 2008, house prices, home construction and population growth appeared to be locked in an ever-increasing upward trend. With little historical experience to the contrary, water right market prices similarly appeared to be driven by real estate development.

  6. Library Resource
    Articles et Livres
    décembre, 2013
    Groenland, États-Unis d'Amérique, Antarctique

    We have produced the first 30 m resolution global land-cover maps using Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) data. We have classified over 6600 scenes of Landsat TM data after 2006, and over 2300 scenes of Landsat TM and ETM+ data before 2006, all selected from the green season. These images cover most of the world's land surface except Antarctica and Greenland. Most of these images came from the United States Geological Survey in level L1T (orthorectified).

  7. Library Resource
    Articles et Livres
    décembre, 2015
    États-Unis d'Amérique

    The Brook Trout Salvelinus fontinalis is an important species of conservation concern in the eastern USA. We developed a model to predict Brook Trout population status within individual stream reaches throughout the species’ native range in the eastern USA. We utilized hierarchical logistic regression with Bayesian estimation to predict Brook Trout occurrence probability, and we allowed slopes and intercepts to vary among ecological drainage units (EDUs).

  8. Library Resource
    Articles et Livres
    décembre, 2015
    États-Unis d'Amérique

    The fate of ecosystem services (ESS) in the United States depends on the actions of private landowners and operators (‘farmers’). This work uses a mixed qualitative and quantitative method to understand farmer knowledge of ESS and willingness to manage lands from an ESS perspective. Fourteen interviews were conducted to analyze farmer understanding of ESS within the context of conservation management.

  9. Library Resource
    Articles et Livres
    décembre, 2014
    États-Unis d'Amérique

    Urban areas contribute disproportional nitrogen (N) loads to downstream aquatic ecosystems resulting in potential hypoxic ‘dead’ zones. Riparian areas along streams and rivers reduce inorganic N concentrations through denitrification, an anaerobic microbial process. Our study objective was to investigate the denitrification potential of riparian areas with differing land cover composition along the Licking River in Kentucky, USA – a tributary of the Ohio River. For one year we collected monthly samples from four sites along a 60 km reach of the Licking River.

  10. Library Resource
    Articles et Livres
    décembre, 2011
    Mexique, États-Unis d'Amérique

    A novel approach to image radiometric normalization for change detection is presented. The approach referred to as stratified relative radiometric normalization (SRRN) uses a time-series of imagery to stratify the landscape for localized radiometric normalization. The goal is to improve the detection accuracy of abrupt land cover changes (human-induced, natural disaster, etc.) while decreasing false detection of natural vegetation changes that are not of interest. These vegetation changes may be associated with such phenomena as phenology, growth and stress (e.g.

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