Showing 4 results for Habitat
S.j. Khajeddin,
Volume 4, Issue 4 (1-2001)
Abstract
Astracantha adscendens is an endemic species in Iran growing on alpine and above alpine timberline habitats on the Zagross Mountain Range. These habitats are characterized by steep slopes, heavy snowfalls and long ice formation periods. The present study was carried out in Chelgerd, Bakhtiari, and Fereidan, Isfahan. Slopes, elevation above sea-level, and magnetic north azimuth were measured. The canopy cover was also measured along four radii in upward, downward, left and right directions. Regression analysis was performed for the measured values of plant and environmental factors.
The results revealed that the upward radius had a high negative correlation with slope changes while the downward radius showed no relationship with slope variations. The two left and right radii had a high and positive relationship with each other, both reducing in length as the slope steepness increased. Shrub volume decreases with increasing slope steepness. Plant shape was classified into seven groups using Sorenson similarity index and constructing the dendrogram. Snow pressure bends the stem toward the soil surface. Snow gliding pressure scratches stem and its base buds above the bent stem. Soil and debris move downward the slope as a result of snow gliding and rainfall runoff as well as wildlife and domestic animals. Snow gliding along with other natural factors have various effects on A. adscendens plant form which can be grouped under three categories: direct mechanical effect of snow, physiological effect of snow, and indirect effect of precipitation and wildlife. The environmental factors and plant physiological responses to them change the A. adscendens plant form from a funnel or ob-conical shape to a semi-funnel or semi ob-conical form.
M Hemami, F Hazeri, S.j Khajedin,
Volume 13, Issue 48 (7-2009)
Abstract
Population of Persian gazelle has been declining in recent decades and as a result, this species was added to the IUCN list of threatened species in 2006. However, there is paucity of ecological data about this species within its range. Mooteh Wildlife Refuge is one of the best habitats of Persian gazelle in Iran where one of the biggest populations of this species live. Habitat selection by threatened Persian gazelle was studied in three seasons in Mouteh wildlife refuge. Habitat use was related to plant communities and plant vegetation variables using clearance transect pellet group counts carried out every 45th day. The effects of water resources and disturbance by man and livestock were controlled. Habitat selection was significantly different between seasons and plant communities. Salt bearing clay soils with a high diversity of holophyte plants were mostly used particularly over winter, while Artemisia- Zygophyllum community was avoided in all seasons. Minimal models resulting from multiple regression retained a number of vegetation variables in each season including a negative effect of Tamarix sp. and Alhaji camelorum and a positive effect of Halocnemum strobilaceum and Salsola dendroide in autumn and winter. It is concluded that selection of habitat by Persian gazelle changes by seasons and that salt-bearing soils and Artemisia-Salsola community are the most important habitats for gazelles in Mouteh Wildlife Refuge.
A. H. Gharehsheikhloo , M. R. Vahabi , H. R. Karimzadeh ,
Volume 14, Issue 53 (10-2010)
Abstract
In order to classify and determine the plant communities in Karkas mountainsides, central Iran, quantitative data of 46 environmental characteristics including climate (12 characteristics), soil (26 characteristics), geology and physiology (8 characteristics), were analyzed based on partial Euclidean distance indicator using minimum variation method. The results showed the clustered separation of studied sites at 68% similarity level with three different growth places. Of these 46 factors, 24 factors (8 climate characteristics and 16 soil characteristics) were effective in this classification at 95% certainty level. Only 24 of these 46 factors were effective in this classification at 95% certainty level. These 24 effective factors were divided into 8 climate and 16 soil characteristics. In another classification, combinational percentage index of 17 plant species were investigated as an effective factor in separating growth place and determining the plant communities. Result of cluster classification indicated that the studied sites cold be classified to 3 habitats.
M.j. Aghasi, S.a.r. Mousavi, M. Tarkesh, S. Soltani,
Volume 28, Issue 3 (10-2024)
Abstract
Astragalus is the vegetation of many mountains of Iran's plateau and plays a major role in providing ecosystem services due to its pillow shape and deep rooting system, they facilitate the control and penetration of precipitation into the soil. The correlation of Astragalus ecosystems with arid and semi-arid climates has made them vulnerable to climate change. In this study, a runoff yield map based on the Budyco curve under current and future conditions of climate change (2050) was prepared using climate and temperature data from the Chelsea site (CanESM2 GCM) in TerrSet software and by using maps of sub-watersheds, annual precipitation, annual potential evapotranspiration, soil depth, plant accessible water and the current and future "Land Cover - Land Use" map, with a combination of field methods and species distribution models at the local scale of the Shur River watershed of Dehaghan (Central Zagros). Finally, the excess runoff damage produced due to climate change was estimated using the replacement cost method. The results indicated an increase in the annual runoff volume of the watershed from 70 million cubic meters to 105 million cubic meters under climate change conditions for the RCP26 scenario in 2050. Taking into account the cost of 10 million Rials for controlling 530 cubic meters of runoff through various watershed management projects, preventing the damages of excess runoff produced requires a credit amounting to 660 billion Rials based on the present value. This study proved the ability of TerrSet software to predict and produce an ecosystem service map of runoff yield under climate changes or land use changes and with the purpose of valuation on a local scale. Also, the above valuation can be the basis for planning and providing credit for the study and implementation of watershed management projects to deal with the threats of climate change.
