Seyed Taghi Mirhaji; Morteza Akbarzadeh; Farhad Azhir
Volume 25, Issue 1 , April 2018, , Pages 54-62
Abstract
Awareness of annual and monthly production of various rangeland types is essential for efficient management of rangelands. It would be achievement by determining the relationship between plant forage production and climatic variables affecting them especially rainfall which would make easier management. ...
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Awareness of annual and monthly production of various rangeland types is essential for efficient management of rangelands. It would be achievement by determining the relationship between plant forage production and climatic variables affecting them especially rainfall which would make easier management. Achieving this goal is facilitated by determining the relationship between the amount of forage production and climatic variables affecting it, especially rainfall, in rangelands. Firuzkuh rangelands were studied to determine the relationship between rainfall and shrub forage production during 2006-2010. For this purpose, the annual and monthly forage production was measured during plant growth season in research exclosure plots by clip and weigh method. Each plant species studied had a specific production during the grazing season in different years. Relationship between forage production and precipitation in periods of winter and spring as well as each month of winter and spring was estimated. Results showed that correlation between the forage production of study species and precipitation in different periods including crop year (0.06 - 0.42), winter and spring (0.01-0.23), March and spring (0.13 -0.35), March and May (0.06 – 0.45), February to June rainfall (0.13 – 0.40), was positive and reached its highest level in June (0.63 -0.94). A significant relationship was found between the forage production of Acantholimon erinaceum, Acanthophyllum spinosum, Astragalus gossypinus, Onobrychis cornuta and Thymus fedtschenkoi and June rainfall.
Aezam Khosravi Mashizi; Gholamali Heshmati; Najmeh Faryabi
Volume 21, Issue 4 , March 2015, , Pages 571-579
Abstract
Negative and positive interactions among plants have important role for species coexistence and community diversity. The strength and direction of the interaction effect may change with environmental disturbances such as grazing and fire. This study was aimed to evaluate the effects of environmental ...
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Negative and positive interactions among plants have important role for species coexistence and community diversity. The strength and direction of the interaction effect may change with environmental disturbances such as grazing and fire. This study was aimed to evaluate the effects of environmental disturbances such as fire and grazing on interactions between shrubs and herbs in rangelands of Goghar Bafte. Hence, beneath 20 dominant species of Artemisia aucheri and 20 open patches, a quadrate of 20 cm×20 cm was plotted and the variation in the biomass, richness and vegetation cover of herbs were measured in regions under exclosure, fire and grazing. Results showed that biomass and vegetation cover of herbs were increased by shrub presence because of positive interaction between shrubs and herbs inside exclosure. Although the facility of shrubs was reduced by grazing and fire, its rate was not equal in both places. Under grazing, interaction between shrubs and herbs remained positive but shrubs were severely damaged by fire and the interaction between species altered from positive to negative. The overall conclusion is that fire plays a more important role in changing the interaction between shrubs and herbs.