distribution of the genus chondrostoma in iran, which is mostly known from the caspian sea, tigris river, kor river and esfahan basins was mapped. the kura nase, chondrostoma cyri is reported from armenia, georgia and iran and it is found in the streams and rivers draining to the western coast of the caspian sea from the kuma river in the north southward to the kura and aras river basins in the...

Density, diameter distribution and height-diameter (H-D) pattern of a forest stand are of primary importance in deriving various stand characteristics, but measuring diameters and heights of a tree stock is rather time-consuming. That is why theoretical diameter distribution and H-D models are usually employed. We examine the prediction of them for Scots pine sample plots using information obta...

the location of extracellular enzyme activities in soil aggregates can be influenced by slope position. this study aims to determine the effect of slope position on aggregate distribution of organic c and l-glutaminase activity. the soils were collected from different slope positions (shoulder, backslope, footslope and toeslope) at two pasture ecosystems (fereydoonshahr and chelgerd, central ir...

since density is considered as one of the most important numerical indices to explain quantitative values of a plant community by affecting on many aspects and activity of ecosystem, on the other hand, awareness about plants distribution pattern in environment is an essential preparation for measurement and study of vegetative cover, therefore, in this research determination of density and dist...

Simple network-level measures can tell us a great deal about the shape of a network, e.g., the mean degree, the degree distribution, local or global clustering coefficients, edge reciprocity, mean geodesic distance or diameter, etc. However, these simple measures are not sensitive to how the structural pattern they measure might vary non-uniformly across the network. For example, reciprocity te...