Document Type : Research Paper
Authors
Department of Nature engineering, Faculty of Natural Resources and Earth Sciences, University of Shahrekord, Shahrekord, Iran
Abstract
Assessing rangeland health is of great importance due to its impact on ecosystem sustainability. This study investigated the relationship between evaluation criteria of rangeland health and functional diversity indices in part of the Sabzkouh Protected Area (Chaharmahal Va Bakhtiari Province, Iran). For this purpose, four rangeland sites with different grazing intensities (reference, light, moderate, and heavy grazing) were selected. In each site, two representative areas were sampled using three 30×30 meter macroplots. Plant functional traits, including plant height, various leaf traits, mean crown diameter, and growth form, were measured. Functional diversity indices, including Functional Richness, Functional Evenness, Functional Dispersion, Rao’s Quadratic entropy and growth forms, were calculated using the FD package in R 4.4.2. Additionally, three evaluation criteria of rangeland health, including soil/site stability, hydrologic functions, and biotic integrity, were evaluated. The data were analyzed using ANOVA, correlation, and univariate regression tests, employing the aov and duncan.test functions and the R packages ggcorrplot, dplyr, reshape2, ggpubr, and ggpmisc for 21 data pairs. Results revealed that soil/site stability, hydrologic function, and biotic integrity had significant positive relationships with certain functional traits such as leaf dry weight (R² = 0.6), leaf area (R² = 0.5), leaf length (R² = 0.5), perennial forb (R² = 0.3), and perennial grass (R² = 0.5). Conversely, negative correlations were observed with other indices including functional divergence (R² = 0.5), functional dispersion (P < 0.05), mean crown diameter (P < 0.05), annual grass (P < 0.05), and shrub (R² = 0.5). These findings emphasize the importance of incorporating quantitative biodiversity indices alongside qualitative assessments to improve rangeland management and develop a quantitative evaluation protocol.
Keywords
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