جستجوی مقالات مرتبط با کلیدواژه « Species Diversity indices » در نشریات گروه « جنگلداری »

To investigate the effect of recreation on plant species diversity and edaphic characteristics, this study was done in Gamboueh Forest Park of Ahvaz with an area of 60 hectares in 1398. For this study, sampling method was used using a linear transect with a length of 300 meters and sampling parts were randomly used at 50-meter intervals. In order to study the tree and shrub cover in two recreational and non-recreational areas, 24 sample plots of 20×20 m (400 m2) were placed and in the center of each plot, in order to study the grass cover, the sample plots of 8×8 m (64 m2) were implemented. In this study, 28 plant species were identified. Conventional comparative analysis (CCA) showed that the control area and the recreation area each formed a separate ecological group in the area. In terms of plant species composition, the highest values of Simpson species diversity indices (0.33±0.023), Shannon-Wiener (0.44 ±0.012) and Shannon-Wiener uniformity index (0.6±0.003) And plant species richness (2.9±0.61) was estimated in the control area. Examination of edaphic conditions showed that recreation could not have an effect on soil texture, but characteristics such as porosity, nitrogen, potassium, phosphorus and organic matter decreased under the influence of recreation and characteristics of bulk density, saturated moisture, electrical conductivity and lime increased significantly. The results of this study indicate that recreation without observing technical and scientific criteria can reduce the density and diversity of grassland vegetation in the region, which can have destructive effects on habitat.

Awareness of species diversity changes in effect of forest management and utilization, will give us valuable information from forests stand that help us in correct decision making, future planning and sustainable management. The aim of this study is evaluation of tree species diversity indices in natural forest stands compared to managed forest stands in a part of district one and two Shast Kalate forests of Gorgan. The circular plots with 0.1 ha area were collected in a systematic random sampling design. In each plot, we recorded species and their diameter for all trees with a diameter at breast height (D.B.H) greater than or equal to 12.5cm and richness, evenness and diversity indices computed in all plots. Also, the independent T test was used for comparing richness, evenness and diversity indices between natural and managed forest stands. Also, the rarefaction method was used for accumulation pattern of species. The results of statistical test showed that differences in Menhenick and Margalef richness indices, Simpson Reciprocal (Hill), Shannon-Wiener and common species diversity, Simpson, Camargo, Smith-wilson and Modified nee evenness indices between managed forest stands and natural stands forest in 95% probability are significant that represented the correct management and positive trend in managed forest stand. Also this result expressed that forest management and utilization were preserved the tree diversity in this study area and managed forest didn’t have distance from evolutionary trend.