overgrazing, via harvesting of forage species and decrease the other herbs, is of progressive factors in biodiversity destroying. in order to investigate the animal grazing impacts on changing of plant structure and diversity, we selected the comparison between this effect with exclosure area, and proving of the excluded area effects on plant diversity; two sites of kojour rangeland, mazandran ...

Monitoring fish assemblages is needed to assess whether Marine Protected Areas (MPAs) are meeting their conservation and fisheries management goals, as it allows one to track the progress of recovery of exploited species and associated communities. Underwater Visual Census techniques (UVC) are used to monitor fish assemblages in MPAs. UVCs should be adapted to fish abundance, body-size and beha...

This study presents the effect of water level variation on the assemblages of herbaceous species in Mourão I Reservoir, Lago Azul State Park, Southern Brazil. The structure and distribution of populations was examined in February (dry period) and April (rainy period), 2011, in two transects. These transects started at the forest edge towards the center of the lake. The end of the transect coinc...

The recreational load is an important factor in transforming the living conditions of organisms urban environment. This article examines role recreation as a driver changing habitat soil micromolluscs park environment landscape. hypothesis that exposure changes hierarchical organization spatial distribution micromollusc community was tested. An experimental polygon located Novooleksandrivskiy P...

Between 1945 and 1965, 1.82 million hectares, or about 17 percent of the total commercial forestland in Oregon, were treated with 2.02 million kg DDT. Detectable residues of this insecticide might be present in forest soils, even those which have never received a direct application of insecticide. Forest floor and mineral soil samples were collected along four east-west transects across the Coa...

Fine roots ( 1 mm diameter) are critical in plant water and nutrient absorption, and it is important to understand how rising atmospheric CO2 will affect them as part of terrestrial ecosystem responses to global change. This study’s objective was to determine the effects of elevated CO2 on production, mortality, and standing crops of fine root length over 2 years in a free-air CO2 enrichment (F...

The temporal and spatial variabilities of phytoplankton absorption coefficients (aph(λ)) and their relationships with physical processes in the northern South China Sea were examined, based on in situ data collected from two cruise surveys during May 14 to 25, 2001 and November 2 to 21, 2002. Significant changes in the surface water in aph values and B/R ratios (aph(440)/aph(675)) were observed...

in this study variations of field data such as temperature, salinity and density in and across the transects of chahbahar bay were analyzed using ctd data acquired between winter 2006 and spring 2007 (winter monsoon).the results showed that thermocline layer intensify in mouth of bay between 2m and 6m with 7.81 ?c decrease before the gonou hurricane occured (mid-may 2007). below thermocline lay...

Semivariograms were used to exploit the spatial information inherent in digital imagery of a variety of Douglas-fir [Pseudotsuga menziesii (Mirbel) Franco] forest stands in the Pacific Northwest region of the United States. Calculations involved digital numbers from single transects of pixels representative of each stand and from a full spatial matrix of pixels from each stand. Digitized aerial...

to find the effect of atriplex canescens on soil chemical properties, two adjacent areas, each with and area of 1 ha, were selected in hossein abad hapeshloo shahryar. in one area it was planted atriplex canescens in 2003 while the later one without atriplex canescens was considered as control area. to sample soil, random- systematic method was used along 3 transects with a length of 100 m. in ...