The effect of water spreading system on the functionality of rangeland ecosystems

Abstract

In recent decades, the control of floods is an efficient management practice for the rehabilitation of rangelands in most arid and semiarid areas. To evaluate the benefits, we used the Landscape Function Analysis (LFA) method to assess the function of patches and qualitative capability of a rangeland ecosystem in Gareh Bygone region, Fars province, southwestern Iran. Landscape functionality depends on soil, water and nutrient (collectively called "resources") conservation and use within a given ecosystem. Many landscapes are naturally heterogeneous in terms of resource control and possess patches, where resources tend to accumulate, and inter-patches. Assessing rangeland health and function of landscape patches in response to environment and management can give rise to correct management decisions for qualitative improvement of the ecosystem. Therefore, our study area was divided into two parts, i.e. water spreading and control parts, and sampling was done using LFA method in each part separately. Structural parameters, including the number, length and width of patches, and the mean length of inter-patches, were determined by the method to characterize the functional status of the monitoring sites. For each patch/inter-patch type identified in the transect organization log, we recorded its soil surface properties classified according to the Soil Surface Assessment Method. The density, canopy cover and composition of plants were then assessed. The results showed that the number of ecological patches and their dimensions were significantly increased in the water spreading site. Soil stability and the values of nutrient cycling indices were increased but the infiltration values were decreased in the water spreading site. It could be related to the effect of suspended materials transported by floods to the soils in the study area. The improvement of ecological patches and rangeland ecosystem was achieved where water spreading systems were practiced. Therefore it can be concluded that water spreading as a management plan plays an important role in arid land ecosystem functionality.

Indicators of landscape organization and functionality in semi-arid former agricultural lands under a passive restoration management over two periods of abandonment

“…Our results are in agreement with the higher levels of infiltration and nutrient cycling indexes found in shrub patches in semiarid degraded steppes of Spain (Maestre and Cortina, 2004). These results can be explained by the role of shrub patches in maintaining soil stability (Bidgoli et al, 2012) and improved infiltration due to root development as found in rangeland ecosystems of Iran (Forouzeh and Sharafatmandrad, 2012).…”

“…These processes allow the landscape to function as a biogeochemical system and also to evaluate its dysfunctionality (Tongway and Hindley, 2004). Hence, the LFA methodology has been widely applied to reflect the status of critical ecosystem processes in arid lands of Australia (Ludwig et al, 2004;van der Walt et al, 2012), Iran (Ata Rezaei et al, 2006Bidgoli et al, 2012;Forouzeh and Sharafatmandrad, 2012;Siroosi et al, 2013), Mongolia (Addison et al, 2013), and Spain (Maestre and Cortina, 2004;Cortina et al, 2006;Maestre and Puche, 2009). In South American deserts, the land degradation is increasing due to intensive land use (Villagra et al, 2009), consequently emphasizing the interest in understanding ecosystem changes triggered by activities such as agriculture (Bertiller et al, 2002;Salazar et al, 2015).…”

Spate Irrigation of Barley Through Floodwater Harvesting in the Gareh-Bygone Plain, Iran

“…Therefore, a technique called floodwater spreading (FWS) developed by Phillips (1957) and improved by Newman (1963) and Quilty (1972), has been implemented at 36 FWS project locations in Iran since 1983 (Ghayoumian et al, 2002). The system serves as spate irrigation (Tesfai and Stroosnijder, 2001;Kowsar, 2011), artificial recharge (Hashemi et al, 2013(Hashemi et al, , 2014, soil enrichment and stabilization (Ghazavi et al, 2010), rangeland improvement (Mesbah and Kowsar, 2010;Forouzeh and Sharafatmandrad, 2012), flood mitigation (Ghayoumian et al, 2005;Kheirkhah Zarkesh, 2005), combating desertification (Kowsar, 2009), and in general, changing the outlook of deserts as potential living spaces. It is estimated that at present between 450 000 and 800 000 ha are under spate irrigation in Iran (Kowsar, 2011;Mehari et al, 2011).…”