Investigation of Stability and Relationships between Species Diversity Indices and Topographical Factors (Case Study: Ghorkhud Mountainous Rangeland, Northern Khorasan Province, Iran)

Document Type : Research and Full Length Article


1 Range Management, Gorgan University of Agricultural Sciences and Natural Resources Sciences, Gorgan

2 Gorgan University of Agricultural Sciences and Natural Resources Sciences, Gorgan

3 Natural Resources Organization, North Khorasan


One of the main objectives of ecosystem management is to preserve the species
diversity. Many researchers regard higher species diversity as the stability of ecological
systems. The aim of this study is to investigate the stability and relationships between
topographical factors with diversity indices in Ghorkhud mountainous rangeland in
northern Khorasan province, Iran. For data sampling (2012), land units were specified.
Floristic list was prepared and minimal area was determined based on the nested plot
(Braun-Blanquet method). 120 plots of 1m2 were selected and within each plot, the
presence of species and cover percent were estimated. For data analysis and means
comparison of species diversity between the study sites, One-way ANOVA and Duncan
tests were used. The species diversity was investigated using numerical indices and
stability of the habitat was determined using parametric indices. The results showed that
species diversity was decreased due to the increased altitude. Diversity indices were
increased by the increased slope percent. Also, eastern slopes had the most diversity as
compared to the other driving directions since the communities with high and low
diversities generally follow the Log-Normal and Geometric models, respectively.
According to our results, the areas with light slopes, middle altitudes and north and west
directions followed the Log Normal distribution which had the most stable levels. It was
concluded that the area with Log-Normal model represents a relatively stable communities
with medium to high species richness.


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