Effects of Topographical Factors on Distribution of Plant Communities in Semi-Steppe Grasslands (Case Study: Ghorkhud Region, Northern Khorasan Province, Iran)
الموضوعات :
Negin Nodehi
1
(M.Sc. Student of Range Management, University of Agricultural Sciences and Natural Resources Sciences, Gorgan, Iran (Corresponding Author))
Mousa Akbarlou
2
(Assistant Professor, University of Agricultural Sciences and Natural Resources Sciences, Gorgan, Iran)
Adel Sepehry
3
(Professor, University of Agricultural Sciences and Natural Resources Sciences, Gorgan, Iran)
Hasan Vahid
4
(Expert M.Sc. of Natural Resources Organization, Northern Khorasan, Iran)
الکلمات المفتاحية: furrow, Grassland, Topography factors, Ghorkhud protected area, Plant communities,
ملخص المقالة :
Abstract. The purpose of this study was to investigate the effects of topographical factors on the classification of grassland plant communities in the rangelands of Ghorkhud, Northern Khorasan Province, Iran. For sampling, land units were specified. A floristic list was prepared using minimal area method based on the nested plot (Braun-Blanquet method). 116 10m2 furrows were selected. Within each furrow, the presence and cover percent were estimated. On the basis of Braun-Blanquet classification method, cover percent of each species was ranked and the representative matrix was established. Vegetation was characterized by the means of Braun-Blanquet classification method using TWINSPAN level 2. To determine the relationships between vegetation and effective topographic factors, a Canonical Correspondence Analysis (CCA) method was used. Results showed that the region's vegetation was divided into four plant communities including Stipa barbata-Festuca ovina, Festuca ovina-Agropyron trichophorum, Stipa hohenackeriana-Festuca ovina and Agropyron cristatum-Stipa barbata, respectively. Based on results of CCA, the first and second axes (Eigenvalue=0.39, 0.29 ) were accounted for 50.2 and 37.7% variations, respectively and totally, the first two axes were accounted as 82% of total variation concerning the environmental factors such as aspect with the first axis and elevation and slope with the second axis.
Brauch, Z., 2005. Vegetation-environmental relationships and classification of the seasonal savannas in Venezuela. Jour. flora, 200: 49-64.
Braun-Blanquet, J., 1972. Plant Sociology: The study of plant communities, hafner publishing, New York.
De Martone, M., 1942. Geography universelle, VI: I, 140.
El-Ghani, M. M., 1998. Environmental correlates of species distribution in arid desert ecosystems of eastern Egypt go vernal. Arid Environments, 38: 297-313 pp.
Gauch, H. G., 1982. Multivariate analysis in community ecology, Cambridge University Press Cambridge, UK. 360p.
Goodall, D. W., 1954. Objective methods for the comparison of vegetation III. An essay in the use of factor analysis. Australian Jour. Botany, 1: 39-63.
Jongman, R. H. G., Ter braak, C. J. F. and Van Tongeren, O. F. R., 1987. Data analysis in landscape ecology. Pudoc. Wageningen. 299 p.
Keshtkar, H., 2007. Investigated the ability of satellites to map land cover (case study: Ghorkhud protected area in northern province). Range management master's thesis, department of natural resources, Tehran university. 141 p.
Layon, J. and Sagers, L., 2002. Correspondence analysis of functional groups in a riparian landscape. Jour. Plant Ecology, 164: 171-183.
Mirmohammadi, S. A., Amini, M. and Hajiabadi, A., 2002. Factors affecting the establishment of four Halophytes in the north marshes Gavkhooni using the ordination method. Jour. Agricultural Sciences & Natural Resources, 6 (2): 215-229. (In Persian).
Moghaddam, M., 2001. Vegetation ecology and descriptive statistics. Tehran university press, 285 p. (In Persian).
Moghaddam, M., 2006. Terricolous plant ecology. Tehran University Press, 701 p. (In Persian).
Moslemi, M., 1997. Relationship between vegetation and soil using the ordination method, the national park of Kolahghazi, range management master's thesis, University of Tarbiat Modarres. 106 pp. (In Persian).
Naqinezhad, A. R., Jalili, A., Attar, F., Ghahreman, A., Wheeler, B. D., Hodgson, J. G., Shaw, S. C. and Maassoumi, A., 2009. Floristic characteristics of the wetland sites on dry southern slopes of the Alborz Mts., N. Iran: The role of altitude in floristic composition. Jour. Flora, 204: 254–269.
Noy- Mayer, I., Tadmor, N. H. and Arshan, G., 1970. Multivariate analysis of desert vegetation, Israel Jour. Botany, 19:91-561.
Shaltout K. H., Sheded, M. G., Kady, H. F. E. and Al-Sudani, Y. M., 2002. Phytosociology and size structure of Nitraria retusa along the Egyptian Red Sea coast. Jour. Arid Environment, 53: 331-345 pp.
Sharifi Niyaragh, J., 1997. The relationship between species diversity and vegetative forms of natural grasslands in Ardabil. Jour. Research and Development, 33: 26-31. (In Persian).
Shokri, M. Bahmanyar, M. R. and Tatiyan, M. R., 2003. Ecological study of vegetation summer pastures Hezarjarib Behshahr. Iranian Jour. Natural Resources, 56 (1, 2): 131-141. (In Persian).
Yibing, Q., 2008. Impact of habitat heterogeneity on plant community pattern in Gurbantunggut Desert. Geographical Science, 14(4): 447-455.
Zare Chahuki, M. A., 2008. investigated the relationship between species diversity and environmental factors in pastures Poshtkuh
