Evaluation of Structural Biodiversity in Natural Systems of Arid and Semi-arid Regions: Plants and Arthropods

Plants and arthropods are the main elements of biodiversity in ecosystems. In order to evaluate structural biodiversity of plants and arthropods in natural systems of arid land, a study was carried out in Shirvan, Mashhad and Gonabad, three regions of Razavi and Northern Khorasan provinces, Iran. In each region, 10 areas of natural systems selected and sampling was done in these selected areas. Plant sampling performed by quadrates and arthropod sampling was done by sweep net. Species richness of plants in natural systems of Mashhad and Gonabad was greater than Shirvan. In the same time, species richness and abundance of insects in the natural system of Shirvan were greater than two other systems. Furthermore, species richness and abundance of spiders in the natural system of Shirvan were greater than two other systems. Results showed that biodiversity of plants and arthropods were affected by increasing of mean annual temperature and decreasing of mean annual precipitation.