the study was performed for assess the environmental factors affecting weed species diversity and composition of wheat (triticum aestivum l.) fields in jajarm, north-khorasan of iran, in 2009. the crop management (herbicide, amount of nitrogen applied and preceding crop type) and edaphic factors (ph, texture and content of phosphorus) of 16 fields were collected. shannon’s diversity index, spec...

The tree species diversity in mixed stands of beech and valuable broadleaves was researched in the area of the National Park `Djerdap` on fifteen sample plots (total study area of about 5 ha). For this purpose, the following diversity measures were applied: (1) Shannon`s index H', (2) Simpson`s index (Simpson 1949), (3) McIntosh`s diversity index D' (McIntosh 1967), (4) Hill’s N1 diversity numb...

our planet is threatened by nuclear wars, climate change and degradation of biodiversity. the first two dangers are relatively focused on, but biodiversity degradation is not properly considered yet. species diversity is mostly composed of biodiversity and is considered an index of changes in ecosystems. many of researchers think of higher species diversity as an index of bio-system’s stability...

In this paper, we argue that the metaphor form of a comparison (i.e., a topic-vehicle pair) is preferred over, and more comprehensible than, the simile form when the interpretive diversity for that comparison is high. Interpretive diversity refers to the richness of the figurative meaning of a comparison; it is high to the extent that more features or properties are related to the figurative me...

plant diversity conservation is a main objective in rangelandmanagement. plant diversity is a suitable index for showing the changes ofvegetation in rangelands and has a high correlation with ecosystem parameters.therefore, using this index it is possible to find the changes and manage theecosystem correctly. the current research was performed to determine the speciesdiversity in fashandak rang...

Plant Diversity conservation is a main objective in rangelandmanagement. Plant diversity is a suitable index for showing the changes ofvegetation in rangelands and has a high correlation with ecosystem parameters.Therefore, using this index it is possible to find the changes and manage theecosystem correctly. The current research was performed to determine the speciesdiversity in Fashandak rang...