Résultats de la recherche | Land Portal

Résultats de la recherche

Showing items 1 through 9 of 3160.
  1. Library Resource
    Articles et Livres
    décembre, 2012
    États-Unis d'Amérique

    The relationship among land cover, topography, built structure and stream water quality in the Portland Metro region of Oregon and Clark County, Washington areas, USA, is analyzed using ordinary least squares (OLS) and geographically weighted (GWR) multiple regression models. Two scales of analysis, a sectional watershed and a buffer, offered a local and a global investigation of the sources of stream pollutants. Model accuracy, measured by R² values, fluctuated according to the scale, season, and regression method used.

  2. Library Resource
    Articles et Livres
    décembre, 2016
    Géorgie, États-Unis d'Amérique

    Geographically isolated wetlands (GIWs) are common features of the Dougherty Plain physiographic region in southwestern Georgia. Due to lack of protection at the state and federal levels, these wetlands are threatened by intensive agricultural and silvicultural land uses common in the region.

  3. Library Resource
    Articles et Livres
    décembre, 2008
    États-Unis d'Amérique

    Policy tools are employed to effect changes in the behaviors of citizens. Policy tools, such as incentives and regulation, act as the medium through which the target population may comply with policy objectives; however, policymakers must choose carefully which policy tools to adopt. Given the predominance of privately-owned forestland in Indiana and the United States, this research explores forest policy tool preferences of family forest owners in southern Indiana. The research is based on data from 309 respondents to a mail survey of landowners in 32 southern Indiana counties.

  4. Library Resource
    Articles et Livres
    décembre, 2008
    États-Unis d'Amérique

    Baseflow and precipitation in the Kickapoo River Watershed, located in the Driftless Area of Wisconsin, exhibit a step increase around 1970, similar to minimum and median flows in many other central and eastern USA streams. Potential effects on streamflow due to climatic and land management changes were evaluated by comparing volumetric changes in the hydrologic budget before and after 1970. Increases in precipitation do not fully account for the increase in baseflow, which appears to be offset by a volumetric decrease in stormflow.

  5. Library Resource
    Articles et Livres
    décembre, 2016
    États-Unis d'Amérique

    Flood regulation is a widely valued and studied service provided by watersheds. Flood regulation benefits people directly by decreasing the socio-economic costs of flooding and indirectly by its positive impacts on cultural (e.g., fishing) and provisioning (e.g., water supply) ecosystem services. Like other regulating ecosystem services (e.g., pollination, water purification), flood regulation is often enhanced or replaced by technology, but the relative efficacy of natural versus technological features in controlling floods has scarcely been examined.

  6. Library Resource
    Documents de politique et mémoires
    décembre, 2002
    États-Unis d'Amérique

    Leafy spurge is an exotic, noxious, perennial weed which is widely established in the north central United States and is an especially serious problem in the northern Great Plains (Bangsund et al. 1999). In 1997, the Agriculture Research Service and Animal Plant Health Inspection Service, U.S. Department of Agriculture, initiated a major Integrated Pest Management (IPM) research and demonstration project to develop and demonstrate ecologically based IPM strategies that can produce effective, affordable leafy spurge control.

  7. Library Resource
    Articles et Livres
    décembre, 2014
    Canada

    Traditional approaches to ecological land classification (ELC) can be enhanced by integrating, a priori, data describing disturbances (natural and human), in addition to the usual vegetation, climate, and physical environment data. To develop this new ELC model, we studied an area of about 175,000� km² in the Abies balsamea–Betula papyrifera and Picea mariana-feathermoss bioclimatic domains of the boreal forest of Québec, in eastern Canada.

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

    Land area planted to row crops has expanded globally with increased demand for food and biofuels. Agricultural expansion in the Dakota Prairie Pothole Region (DPPR), USA affects a variety of agricultural and non-agricultural land-use types, including grasslands and wetlands that provide critical wildlife habitat and other ecosystem services. The purpose of this study was to quantify recent changes in rural land cover/land use, analyze trends, and interpret results in relation to climate, agronomic practice, and ethanol production.

  9. Library Resource
    Articles et Livres
    mai, 2011
    Europe, Amérique septentrionale

    „Kísértet járja be Európát és Észak-Amerikát: az erdőpusztulás kísértete.” Ezzel a drámai hangvételű mondattal kezdődik a World Resources 1986. évi kötetének erdőkkel foglalkozó része, ami a 70-es években kezdődött nagyarányú erdőpusztulás világméretű „jajkiáltása” volt, melynek visszhangja: „Mentsétek meg a Föld erdeit – amíg nem késő, amíg van mit megmenteni és megőrizni!” Nemzetközi tudományos, világméretű társadalmi fórumok témájává vált az erdő. Az emberiség egyre jobban ráébredt arra, hogy az erdő az emberiség létfeltételeinek elengedhetetlen része.

  10. Library Resource
    Articles et Livres
    décembre, 2007
    États-Unis d'Amérique

    The environmental setting (e.g., climate, topography, geology) and land use affect stream physical characteristics singly and cumulatively. At broad geographic scales, we determined the importance of environmental setting and land use in explaining variation in stream physical characteristics. We hypothesized that as the spatial scale decreased from national to regional, land use would explain more of the variation in stream physical characteristics because environmental settings become more homogeneous.

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