Investigating the Change in the Pattern of Crop Dominance in Iranian Agricultural Ecosystems
Jafari Leila1, Sara Asadi2, Asgari Ashkan3
1University of Hormozgan, Horticultural Science Department, Iran
Human have made fundamental changes in his environment in many aspects, and agriculture is no exception. We are witnessing the simplification of agricultural ecosystems, which has affected the biodiversity of agricultural products in different parts of the world, and ultimately human behaviour has changed the natural patterns of several thousand years and its effects are the instability of agricultural ecosystems. In order to investigate the predominance of some species in Iranian agricultural ecosystems in terms of biodiversity, a study was conducted in the period 1991-2018. We used time series of crop area data from 1991 to 2018 for Iran. Also, some biodiversity indicators, including Shannon, Simpson, dominance and uniformity, were used to determine the status of biodiversity. The results showed that wheat and barley species are cultivated in almost all parts of Iran (97% of agricultural areas). Wheat and barley in Iran have about 5.4 and 1.45 million hectares of cultivated area (61.83% of the total area under cultivation of crops and orchards), respectively. The trend of Simpson dominance index fluctuated in the study period but was generally affected by the area of wheat and barley. Also, the Shannon diversity index was strongly influenced by the area of wheat (b = -0.41, r = -0.51 **) and barley (x = -0.09, r = -0.34), so that by increasing the area of wheat and barley, Shannon index decreased. The results show the dominance of these plants and the prevalence of monoculture in Iran, which results in instability and vulnerability of agricultural ecosystems. Due to Iran's arid and semi-arid climate, the dependence of these crops on seasonal rainfall has increased the vulnerability of the agricultural system and food security. As the occurrence of drought in some years studied, the amount of wheat and barley production in Iran decreased significantly. In general, the biodiversity trend of crops in Iranian agricultural ecosystems was a function of the amount of dominance or area of wheat and barley cultivation. In other words, when the area of these two crops in this period decreased due to climatic or political reasons, the amount of diversity indices increased.
Keywords: Barley, diversity, food security, sustainability, wheat
Contact Address: Sara Asadi, Ferdowsi University of Mashhad, Fac. of Agriculture, Mashhaf, Iran, e-mail: saraasadi.saigmail.com