abstract soil, is a reclamable and sustainable source. it is the basis of survival and it’s implication, should be performed on the basis of productivity identification according to scientific and technical rules, we can protect this valuable source, and increase it’s productivity and usage. nowdays, saline soils cover nearly 14.6% of the country area. study areas (kashan’ playa) have saline an...

In disturbance-adapted ecosystems, the removal of disturbance can lead to losses diversity and sometimes irreversible changes in community composition. It is important identify thresholds at which these occur, understand reversibility shifts. We examined this question a vernal pool ecosystem that evolved with low moderate levels grazing disturbance. system, it not clear whether negative effects...

Increased farming intensity led to massive declines across multiple farmland taxa. In Europe, measures introduced counteract these losses include those considered agronomically productive, such as organic farming, well that support no direct production of crops, non-crop flowering fields in conventional systems. We studied biodiversity effects non-productive managed under compared both an organ...

Objective To evaluate the in vitro antibacterial activities of five plant extracts which have been used as traditional medicines by local healers against three multidrug resistant bacteria, namely, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Results The highest mean zone of inhibition (4.66 mm) was recorded from methanol extract of Calpurnia aurea (Ait.) Benth. at a c...

the study of the exclosure effects on the vegetation changes undergrazing and non-grazing conditions in the rangeland areas has particularimportance in the rangeland improvement and revivification projects. theresearch was accomplished in semi-steppe khoybilehvar area, from 1999 to2005. vegetation cover was annually measured within fixed plots during transact.the results showed that during nine...

BACKGROUND AND AIMS Intra-specific variation in nectar chemistry under natural conditions has been only rarely explored, yet it is an essential aspect of our understanding of how pollinator-mediated selection might act on nectar traits. This paper examines intra-specific variation in nectar sugar composition in field and glasshouse plants of the bumblebee-pollinated perennial herbs Aquilegia vu...

in many studies, topographic factors have been considered as an important factor in establishing the vegetation in different ecosystems. so, it affects vegetation composition and diversity by influencing soil moisture, fertility and soil depth. the aim of this research was to investigate the effects of slope, elevation and geographical aspects on species growth, forage production and vegetation...

Human land cover can degrade estuaries directly through habitat loss and fragmentation or indirectly through nutrient inputs that reduce water quality. Strong precipitation events are occurring more frequently, causing greater hydrological connectivity between watersheds and estuaries. Nutrient enrichment and dissolved oxygen depletion that occur following these events are known to limit popula...

the purpose of this study was the introduction of seed accumulation index as a new approach in the evaluation of soil seed bank consistency in the populus caspica in noor reserved forest park. sampling were made above ground vegetation at peak vegetation cover during june 2010 by systematic- selective method. soil samples were collected during late june, late november and early february by hamm...