Studying Short-Time Dynamics of Vegetation and Soil Organic Carbon in a Semi-arid Rangeland (Case Study: Zharf, Khorasan Province, Iran)

Document Type: Research and Full Length Article


1 Research Center for Agriculture and Natural Resources of Khorasan Razavi, Mashad, Iran

2 Rangeland Research Division, Research Institute of Forests and Rangelands, Tehran, Iran


Abstract. Rangeland vegetation dynamics encompass all processes of changes in vegetation composition and structure over time. Investigating the rangeland ecosystem dynamics makes it possible to determine the effects of climatic and management conditions on qualitative and quantitative changes of the vegetation in a specific period of time. Accordingly, data collection and measurements for evaluating vegetation dynamics in rangeland ecosystems of Zharf region in Khorasan province, Iran were conducted from 2009 to 2013. Vegetation variables were measured by the means of 3 transects with the length of 500m and sampling plots. Meanwhile, at the location of each plot, soil moisture content was measured at two depths of 0-15 and 15-30 cm using a Time-Domain Reflectometer (TDR) instrument. At the same locations, soil samples from topsoil layer (up to 15 cm depth) were collected to measure organic carbon. Results showed that at a four-year period, depending on inter-annual changes in rainfall and other climatic parameters and under local management practices, more or less changes occurred in some major vegetation factors such as species and total canopy cover. Changes were more prominent in canopy cover of annual plants, perennial forbs and to some extent in perennial grasses. Changes in soil organic carbon showed a very slow trend. Based on soil texture and variations of seasonal and annual rainfall, soil moisture caused variations in vegetation factors. In the study site, considering the relative stability of soil cover by stones, gravels and plant litter, total soil cover changes were a function of changes in total canopy cover of plants. The results of this study could be considered for proper adjustment of rangeland management in Zharf region.


Arzani, H., Fatahi, M. & Ektesasi, M. R., 1999. Survey on trend of quantity and quality changes of vegetation in Poshtkouh - Yazd rangelands during decade 1990-1999. Pajouhesh & Sazndeghi, 44(3):31-35. (In Persian).

Britta, T., Florian, J., Erwin, Z., Nikolaus, C., Alexander, G., Katja, S. and Jens, O., 2010. Effects of climate change on the coupled dynamics of water and vegetation in drylands. Ecohydrol. 3: 226-237.

Fernandez-Gimenz, M. E. and Allen- Diaz, B., 1999. Testing a non-equilibrium model of rangeland vegetation dynamics in Mongolia. Jour. App. Ecol. 36: 871-885.

Kashki, M. T., Sahmoradi, A., Mohamadi, M. and Namdost, T., 2012. The Final report of the research project "Vegetation dynamics in Khorasan rangeland ecosystems", pages 79. (In Persian).

Navarro, J. M., Galt, D., Holechek, J., McCormick, J. and Molinar, F., 2002. Long-term impacts of livestock grazing on Chihuahuan Desert rangelands. Jour. Range Manage. 55(4): 400-405.

O’Connor, T. G. and Roux, P. W., 1995. Vegetation changes (1949-1971) in semi-arid grassy dwarf shrublands in the Karoo, South Africa: Influence of rainfall variability and grazing by sheep. Jour. Applied Ecology. 32: 612-626.

O’Connor, T. G., 1995. Transformation of a Savana grassland by drought and grazing. African Jour. Range and Forage Science, 12: 53-60.

Sharifi, J. and Akbarzadeh, M., 2009. Survey on vegetation changes under rainfall effect on the Semi-steppe rangelands (Case study: Saeen, Ardabil province), The 4th National Congress on Range and Range management, P: 85. (In Persian).

Yavari, A., Tavakoli, H., Grivani, G., 2003. The final report of the project "of rangeland vegetation Dynamics in semi-arid North Khorasan. Office research agriculture and nature resources in Khorasan.48p. (In Persian).

Yorks, T. P., West, N. E. and Capels, K. M., 1992. Vegetation differences in desert shrub lands of western Utah, Pine Valley between 1993 and 1989. Jour. Range Manage. 45(6): 569-577.

Arzani, H., Fatahi, M. & Ektesasi, M. R. Arzani, H., Fatahi, M. & Ektesasi, M. R., 1999. Survey on trend of quantity and quality changes of vegetation in Poshtkouh - Yazd rangelands during decade 1990-1999. Pajouhesh & Sazndeghi, 44(3):31-35. (In Persian)..