Investigation of the effect of Crataegus species on diversity indices in the natural species (Anagyris foetida L.)

Species diversity is one of the most important topics in vegetation ecology. The aim of this study was to investigate the effects of Crataegus species on diversity indices in the natural population of Crataegus species. For this purpose, 55 samples of 10R circles of 100 × 100 m network with a regular random pattern were identified in a mass with an area of 55 ha in Gilan-e Gharb Kaseh Karan section in Kermanshah province. For harvesting tree and shrub species, the mentioned pieces were used and for herbaceous species, 4 m2 samples were used in the center of the circular pieces. Simpson, Shannon, Mann-Heninck and Margalef diversity indices were calculated for all sample plots. First, the influence of the four geographic directions (east, north, west, and south) and elevation (two elevations) below and above 1100 m on the diversity indices was investigated. In the next phase, four clusters were identified based on the presence and absence of Crataegus species in the sample plots and on the image created using the diversity indices to compare the diversity indices. The statistical results showed that the two factors of geographic direction and altitude had no effect on the diversity indices. However, Crataegus species did affect the diversity indices, such that species diversity was lower in the sample plots where Crataegus species were present.