Document Type : Research Paper

Authors

• Zahra Heidari Ghahfarrokhi ¹
• Pejman Tahmasebi ²
• Ali Asghar Naghipour ³

¹ Ph.D. in Range Management, Department of Nature Engineering, Faculty of Natural Resources and Earth Sciences, Shahrekord University, Shahrekord, Iran

² Associate Professor, Department of Nature Engineering, Faculty of Natural Resources and Earth Sciences, Shahrekord University, Shahrekord, Iran

³ Associate Professor, Department of Nature Engineering, Faculty of Natural Resources and Earth Sciences, Shahrekord University, Shahrekord, Iran.

Abstract

Abstract
Background and Objectives
The functional condition of rangeland ecosystems is strongly influenced by the structural and compositional characteristics of vegetation patches and the intervening interpatch spaces. Landscape Function Analysis (LFA) is a widely used approach for assessing patch organization and evaluating key functional attributes of rangeland ecosystems. The present study aimed to investigate the effects of different livestock grazing intensities on the structural characteristics and functional performance of ecological patches in the rangelands of the Mouteh Wildlife Refuge, central Iran.
Materials and Methods
Three rangeland sites representing different levels of livestock grazing pressure were selected along a grazing-intensity gradient. At each site, two representative areas were selected, and within each area, three transects, each at least 30 m long and separated by more than 60 m, were established. Along the transects, at least three replicates of each major patch type, including shrub patches and plant hummocks (grasses and forbs), as well as interpatch spaces, were identified and evaluated. Three major LFA functional indices, including stability, infiltration, and nutrient cycling, were assessed using LFA software based on 11 soil-surface indicators recorded in the field. In total, 162 patches and interpatch spaces were evaluated. Structural and functional characteristics of patches were compared among grazing intensities using one-way analysis of variance (ANOVA; aov function), followed by Duncan’s multiple range test (duncan.test) in R software.
Results
The highest values of the structural attributes of ecological patches, including the landscape organization index, number of patches per 10 m, patch area index, total patch area, and mean patch length and width, were recorded under light grazing intensity. In contrast, the highest structural values for interpatch spaces, including mean, minimum, and maximum interpatch lengths, were observed under heavy grazing intensity. In contrast to interpatch spaces and plant hummock patches, most soil-surface indicators in shrub patches differed significantly among grazing intensities (p ≤ 0.001 and p ≤ 0.01). With increasing grazing intensity, soil cover, perennial vegetation cover, crust stability, soil erosion type and severity, and slaking-test scores decreased, with the highest values recorded under light grazing (4.000, 7.429, 2.357, 3.500, and 5.429, respectively). Light grazing also resulted in the highest overall stability and infiltration indices (49.619% and 24.351%, respectively), as well as the highest values in interpatch spaces (47.994% and 23.079%), plant hummock patches (42.917% and 22.651%), and shrub patches (56.528% and 29.700%). The highest nutrient-cycling index values were also recorded under light grazing, both overall and in plant hummock patches (15.707% and 15.490%, respectively).
Conclusion
Appropriate rangeland management, particularly in arid and semi-arid environments, plays a critical role in maintaining and improving the structural organization and functional condition of ecological patches. Maintaining adequate vegetation cover and a diverse combination of shrubs, grasses, and forbs can enhance patch connectivity, soil-surface protection, and overall ecosystem functionality. The findings indicate that light grazing pressure is more compatible with the maintenance of organized patch structures, greater patch extent, and higher functional integrity. Consequently, grazing management based on appropriate stocking rates and controlled grazing intensity can contribute to maintaining rangeland resilience, reducing soil degradation, and sustaining key ecosystem functions in the Mouteh Wildlife Refuge.
 

Keywords

• Ecological patches
• grazing intensity
• infiltration
• Landscape Function Analysis (LFA)
• nutrient cycling
• stability