Garlic mustard (Alliaria petiolata), a biennial species, is considered to be among the most troublesome of the invasive plants in the Eastern Deciduous forest of North America. It has been shown to prevent or reduce mycorrhizal colonization of native herbaceous ground layer plants and trees in these forests. It is estimated that 70-90% or more of herbaceous native ground layer plant species for...

At a site in the northwestern Sonoran Desert the percent ground cover for the C $ subshrub Encelia farinosa was eighttimes higher on more arid 20° south-facing slopes than on 20° north-facing slopes at 820 m elevation, and was sixtimes higher on north-facing slopes at a 300-m-lower elevation, also the more arid condition. The ground cover of the C % bunchgrass Pleuraphis rigida decreased over 5...

Fourteen avocado groves were surveyed by leaf samples, beat samples and sticky cards to assess avocado thrips (AT) and natural enemies (NE) populations in avocado trees in 2003. In the groves, the presence of NE and AT between January and September was only slightly affected by a single abamectin treatment, with Chrysopa sp. being the only NE significantly impacted. In untreated groves, conside...

A portion of Arizona's San Pedro River is managed as a National Riparian Conservation Area but is potentially affected by ground-water withdrawals beyond the conservation area borders. We applied an assessment model to the Conservation Area as a basis for monitoring long-term changes in riparian ecosystem condition resulting from changes in river water availability, and collected multi-year dat...

introduction soil is one of the most valuable national resources that can be wasted by erosion phenomenon. therefore, prevention of soil erosion is universally considered. erosion is a process by which soil particles are separated from their original context and can be moved to another location. rill erosion is a kind of water erosion in which detachment and movement of soil particles can be af...