Offered Papers Theme B: Grassland and the Environment
Description
Semi-steppe vegetation with a mean annual precipitation of 250 mm covers 18.5% of Iran (Pabot, 1967). Under full protection, bunch grasses are dominant in this grassland ecosystem. Golestan National Park, (100,000 ha), is representative of this semi-steppe vegetation zone. It has been protected for 40 years and can be considered as a reference area (RA) of semi-steppe vegetation. Under moderate grazing the The Gorokhoud Protected Area acts as a buffer zone to the National Park, with grazing based on permits issued by the Range and Forest Organisation. Parts of the protected area can be considered as a key area (KA), the palatable forbs and grasses were weakened and the dominant species of the steppe region invaded the semi-steppe ecosystems. Under severe grazing in critical areas (CA), most of the perennial grasses and legumes were eliminated and unpalatable spiny and cushion shrubs and annuals invaded. Under heavy grazing the composition of forage species shifts towards undesirable species, especially ephemeral species, and ultimately the plant richness declines. In contrast, under light to moderate grazing the plant diversity improves. However, improving the plant diversity under full protection has been questioned by many authors (West, 1993, Naveh & Whittaker, 1979).
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Plant Species Richness at Three Levels of Range Potential in Semi-Steppe Vegetation of Iran
Semi-steppe vegetation with a mean annual precipitation of 250 mm covers 18.5% of Iran (Pabot, 1967). Under full protection, bunch grasses are dominant in this grassland ecosystem. Golestan National Park, (100,000 ha), is representative of this semi-steppe vegetation zone. It has been protected for 40 years and can be considered as a reference area (RA) of semi-steppe vegetation. Under moderate grazing the The Gorokhoud Protected Area acts as a buffer zone to the National Park, with grazing based on permits issued by the Range and Forest Organisation. Parts of the protected area can be considered as a key area (KA), the palatable forbs and grasses were weakened and the dominant species of the steppe region invaded the semi-steppe ecosystems. Under severe grazing in critical areas (CA), most of the perennial grasses and legumes were eliminated and unpalatable spiny and cushion shrubs and annuals invaded. Under heavy grazing the composition of forage species shifts towards undesirable species, especially ephemeral species, and ultimately the plant richness declines. In contrast, under light to moderate grazing the plant diversity improves. However, improving the plant diversity under full protection has been questioned by many authors (West, 1993, Naveh & Whittaker, 1979).
