distribution and abundance of plants has been correlated with a variety of complex environmental gradients. environmental factors affect plants growth and need to be understood by ecosystem managers. this study was carried out to examine the relationships between site factors and different vascular and non-vascular plants in north of iran. for this purpose, vegetation and soil sampling was perf...

We examined changes in rangeland health in the semi-arid woodlands of eastern Australia at fixed sites between 1989 and 1999. Over the 11-year period there were significant declines in the quality of the vegetation, and changes in plant species were driven largely by seasonality, and to a lesser extent, amount of rainfall. Three indices of rangelands health (composition, function and stability)...

There have been few attempts to develop, test or apply sustainability indicators for natural resource management at a farm-level, and even fewer have fully consulted land users from the initiation of this process. While environmental sustainability indicators need to be accurate and reliable, land users also need them to be rapid, cost-effective and easy to use, in addition to being linked to m...

Ecological sites are the basic entity used in rangeland health assessment. This study evaluates the synergistic use of multiand hyper-spectral satellite imagery for sub-pixel classification of ecological sites in semiarid rangelands. Hyperion and Landsat enhanced thematic mapper (ETM) data are included in a two-step procedure to mapping ecological sites in Patagonian rangelands of Argentina. Fi...

Public land management agencies, such as the Bureau of Land Management (BLM), are charged with managing rangelands throughout the western United States for multiple uses, such as livestock grazing and conservation of sensitive species and their habitats. Monitoring of condition and trends of these rangelands, particularly with respect to effects of livestock grazing, provides critical informati...

Cattle and other livestock excrete endogenous steroid hormones, including estrogens, androgens, and progestins; therefore, allowing grazing livestock direct access to surface waters can result in the release of steroids in agricultural watersheds. Elevated concentrations of steroids are problematic because low concentrations of certain steroids can affect fish reproduction. To assess the occurr...

Afforestation of marginal agricultural lands represents a promising option for carbon sequestration in terrestrial ecosystems. An ecosystem carbon model was used to generate new national maps of annual net primary production (NPP), one each for continuous land covers of ‘forest’, ‘crop’, and ‘rangeland’ over the entire U. S. continental area. Direct inputs of satellite “greenness” data from the...