This study was conducted to investigate the effect of ecological factors on distribution, presence and absence of species Ferula ovina and F. persica in the semi-arid rangelands of Zanjan province, Iran in 2015. The locations of ten 4m2 plots with 15m spacing on three 150 m long transects were systematically randomized and determined in each key area within each hab...

We provide in this paper simulation algorithms for one-sided and two-sided truncated normal distributions. These algorithms are then used to simulate multivariate normal variables with restricted parameter space for any covariance structure.

for optimum planning, utilization, and management of lands, recognition of spatial variability of soil properties is necessary. this research was conducted to evaluate spatial variability of soil properties in 5000 ha of arsenjan plain in fars province. for this purpose, soil salinity, ph, particle size percentage, sodium, potassium, and organic carbon (oc) were measured on a systematic squared...

suspended sediment resulted from distributed soil erosions facilitates nutrient transportation and influences soil depletion. phosphorus (p) is one of the major limiting nutrients controlling eutrophication of surface water. irregular p load pulsed by heavy rainfall may damage the ecological quality of downstream waters. p transport study during rainfall events is important in both predicting a...

Agricultural producers require knowledge of soil water at plant rooting depths,while many remote sensing studies have focused on surface soil water or mechanisticmodels that are not easily parameterized. We developed site-specific empirical models topredict spring soil water content for two Montana ranches. Calibration data sample sizeswere based on the estimated variability of soil water and t...

this study was performed in order to investigate the changes in vegetation and soil properties in compartment no.317 (managed forest) and no.318 (control forest) of jamand district of golband forest in mazandaran (noshahr). for this purpose, random-systematic sampling method with regular grid of 100×200 m was used to locate samples. the plot size was 400 m2 considering to tree and shrub species...

Metacommunity theory provides an understanding of how ecological processes regulate local community assemblies. However, few field studies have evaluated the underlying mechanisms of a metacommunity on a small scale through revealing the relative roles of spatial and environmental filtering in structuring local community composition. Based on a spatially explicit sampling design in 2012 and 201...