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Efficiency and Accuracy of Wildland Weed Mapping Methods

Journal Articles & Books
Diciembre, 2011

Land managers must set weed management priorities if limited resources are to be utilized effectively. Weed surveys and inventories assist land managers in this process by providing information regarding the identity, location, and relative abundance of weeds on their land. Although this information is vital, it can be challenging to select a method that provides the necessary data to meet management objectives while remaining accurate and cost effective. This paper critically evaluates four wildland weed mapping methods.

National Inventory of Landscapes in Sweden (NILS)--scope, design, and experiences from establishing a multiscale biodiversity monitoring system

Journal Articles & Books
Diciembre, 2011
Suecia

The landscape-level and multiscale biodiversity monitoring program National Inventory of Landscapes in Sweden (NILS) was launched in 2003. NILS is conducted as a sample-based stratified inventory that acquires data across several spatial scales, which is accomplished by combining aerial photo interpretation with field inventory. A total of 631 sample units are distributed across the land base of Sweden, of which 20% are surveyed each year. By 2007 NILS completed the first 5-year inventory phase.

Cross-evaluation of measurements of peatland methane emissions on microform and ecosystem scales using high-resolution landcover classification and source weight modelling

Journal Articles & Books
Diciembre, 2011

The methane exchange in an oligotrophic mire complex was measured on the ecosystem and microform scale with the eddy covariance (EC) and the closed chamber technique, respectively. Information about the distribution of three distinct microform types in the area of interest and in each 30min EC flux source area was derived from a high-resolution (1m²) landcover map in combination with an analytical source weight model (Kormann and Meixner, 2001).

Spatial and seasonal variations of polycyclic aromatic hydrocarbons in Haihe Plain, China

Journal Articles & Books
Diciembre, 2011
China

A dynamic fugacity model was developed to simulate the spatial and seasonal variations of PAHs in Haihe Plain, China. The calculated and measured concentrations exhibited good consistency in magnitude with deviations within a factor of 4 in air and 2 in soil. The spatial distributions of PAHs in air were mainly controlled by emission while the seasonal variations were dominated by emission and gas–particle partition. In soil, the spatial distributions of PAHs were controlled by the soil organic carbon content while the seasonal variations were insignificant.

influence of watershed characteristics on nitrogen export to and marine fate in Hood Canal, Washington, USA

Journal Articles & Books
Diciembre, 2011
Estados Unidos de América

Hood Canal, Washington, USA, is a poorly ventilated fjord-like sub-basin of Puget Sound that commonly experiences hypoxia. This study examined the influence of watershed soils, vegetation, physical features, and population density on nitrogen (N) export to Hood Canal from 43 tributaries. We also linked our watershed study to the estuary using a salinity mass balance model that calculated the relative magnitude of N loading to Hood Canal from watershed, direct precipitation, and marine sources.

Evaluations of seasonal habitat variations of freshwater fishes, fireflies, and frogs using a habitat suitability index model that includes river water temperature

Journal Articles & Books
Diciembre, 2011
Japón

The habitats of aquatic organisms, including freshwater fishes (Oncorhynchus masou masou, Plecoglossus altivelis altivel, and Cyprinus carpio), fireflies (Luciola cruciata and Luciola lateralis), and frogs (Anura sp.), were evaluated dynamically in the Natori River basin in the central Miyagi prefecture in Japan using water temperature as an environmental index.

Changes in land cover and vegetation carbon stocks in Andalusia, Southern Spain (1956–2007)

Journal Articles & Books
Diciembre, 2011
Europa

Land use has significantly changed during the recent decades at global and local scale, while the importance of ecosystems as sources/sinks of C has been highlighted, emphasizing the global impact of land use changes. Land use changes can increase C loss rates which are extremely difficult to reverse, in the short term, opposite to organic carbon (OC) which accumulates in soil in the long-term. The aim of this research is to improve and test methodologies to assess land cover change (LCC) dynamics and temporal and spatial variability in C stored in vegetation at a wide scale.

Risk-based modelling of diffuse land use impacts from rural landscapes upon salmonid fry abundance

Journal Articles & Books
Diciembre, 2011

Research has demonstrated that landscape or watershed scale processes can influence instream aquatic ecosystems, in terms of the impacts of delivery of fine sediment, solutes and organic matter. Testing such impacts upon populations of organisms (i.e. at the catchment scale) has not proven straightforward and differences have emerged in the conclusions reached.

Application of Markov-chain model for vegetation restoration assessment at landslide areas caused by a catastrophic earthquake in Central Taiwan

Journal Articles & Books
Diciembre, 2011

The 921 earthquake caused a catastrophic disaster in Central Taiwan. Ten years have passed since the earthquake occurred. Vegetation succession is the basis for establishing a restoration reference which plays an important role in vegetation restoration at landslide sites. Generally, growth conditions for grass are easier and the growth rate is faster than that for trees. Therefore, grass can be considered a pioneer species or an important reference for the early vegetation succession stage. This is the reason why grass is required to be extracted from other land covers.

Long-term water balance and conceptual model of a semi-arid mountainous catchment

Journal Articles & Books
Diciembre, 2011
Estados Unidos de América

Long-term water balance investigations are needed to better understand hydrologic systems, especially semi-arid mountainous catchments. These systems exhibit considerable interannual variability in precipitation as well as spatial variation in snow accumulation, soils, and vegetation. This study extended a previous 10-year water balance based on measurements and model simulations to 24years for the Upper Sheep Creek (USC) catchment, a 26ha, snow-fed, semi-arid rangeland headwater drainage within the Reynolds Creek Experimental Watershed in southwestern Idaho, USA.

Stakeholder and expert-guided scenarios for agriculture and landscape development in a groundwater protection area

Journal Articles & Books
Diciembre, 2011
Dinamarca

Nitrate and pesticide leaching led to the designation of groundwater protection zones in Denmark. The protective measures in these zones often clash with local interests in agriculture. Scenarios were used to evaluate the development of a groundwater protection zone in a farming area. Stakeholders are accorded strong influence on the scenarios. Scenario inputs comprised land cover, land use and farmers' plans and preferences, as registered in interviews with farmers. Scenarios were evaluated regarding the effect on nitrate leaching, extent of pesticide-free area and farm income.

feature extraction software tool for agricultural object-based image analysis

Journal Articles & Books
Diciembre, 2011

A software application for automatic descriptive feature extraction from image-objects, FETEX 2.0, is presented and described in this paper. The input data include a multispectral high resolution digital image and a vector file in shapefile format containing the polygons or objects, usually extracted from a geospatial database.