**Author details**

250 Multivariate Analysis in Management, Engineering and the Sciences

direct relationship with Salinity, Lime, pH and Loam.

statistical significance further extends the utility of CCA.

vegetation pattern.

**Appendix** 

For example all ordination techniques, used in North East rangeland of Semnan, clearly indicated that gypsum, EC, slope are the most important factors for the distribution of the

In the present study, combination of CCA, DCA and RA results showed that *Ar.aucheri-As.spp-Br.to, Artemisia sieberi-Erotia ceratoides, Ar.sieberi-Zy. eurypterum and Zy. eurypterum -Ar. sieberi*  types correlated with A.W2, gr2, O.M2 and clay1 factors and clay in 0-20 depth indicates *Ar.aucheri-As.spp-Br.to* type. *H.strobilaceum* type has strong relationship with soil salinity and heavy texture. This species showed a trend to high soluble rate, salinity and clay percent. S. rosmarinus types indicate soils with light texture and this type directly related to pH and lime percentage while St.barbata-A.aucheri type shows an inverse relation with these factors.

I fact, analysis with DCA gave results similar to CCA, suggesting that there is a relatively strong correspondence between vegetation and environmental factors; with the difference that the DCA is less isolated the site. CCA better shows differences between types. RA shows relationship between sites and factors, like the CCA analysis. RA axis 1 has an eigenvalue of 0.86. RA axis 2 with an eigenvalue of 0.017 is less important. Total variance (inertia) in the species data is 0.8887.In this method eigenvalue of RA axis1 was higher than CCA and DCA axis1. This study reflects that a spatial approach dealing with the most distinctive species of vegetation communities can yield similar results to those obtained with costly physico-chemical analysis and based on complex matrices of plant communities. Similarity as this study, also Jafari et al (2003) in their study in Hoz-e-Soltan Reigion of Qom Province, showed that PCA analysis indicates that Halocnemum strobilaceum type has

May this series of papers serve to enhance the understanding and the proper and creative use of ordination methods in community ecology. Finally, understanding relationships between environmental variables and vegetation distribution in each area helps us to apply these findings in management, reclamation, and development of arid and semi-arid grassland ecosystems (Alisauskas, 1998). The ability to factor out covariables and to test for

Understanding the relationships between ecological variables and distribution of plant communities can provide guidance to sustainable management, reclamation and development of this and similar regions. In this sense, these results increase our understanding of distribution patterns of desert vegetation and related major environmental factors in the North East of Semnan. The results will also provide a theoretical base for the restoration of degenerated vegetation in this area. Understanding the indicator of environmental factors of a given site leads us to recommend adaptable species for

reclamation and improvement of that site and similar sites (Zhang et al, 2005)

*Artemisia sieberi-Erotia ceratoides. A.sieberi-E.ceratoides Halocnemum strobilaceum H. strobilaceum Artemisia sieberi–Zygophylom eurypoides. A.sieberi-Z.eurypterum*  Mohammad Ali Zare Chahouki

*Associate Professor, Department of Rehabilitation of Arid and Mountainous Regions, Natural Resources Faculty, University of Tehran, Iran* 
