Journal of Range and Watershed Managment

Prolonged Assessment of Plant Species Diversity and Richness Indices in the Jishabad Rangeland (Tarom County, Iran)

Document Type : Research Paper

Authors

Farhad Aghajanlou
Peyman Akbarzadeh

Forest and Rangeland Department, Agricultural and Natural Resources Research and Education Center of Zanjan, Agricultural Research, Education and Extension Organization (AREEO), Zanjan, Iran

10.22059/jrwm.2025.398912.1845
Abstract
Rangelands, as one of the vital ecosystems in Iran's arid and semi-arid regions, play a crucial role in biodiversity conservation, soil erosion prevention, and forage supply. In recent years, anthropogenic pressures such as overgrazing and climate change have led to the decline in species diversity and the ecological degradation of rangelands. This study aimed to investigate the trends of plant species diversity and richness indices from 2021 to 2023 (corresponding to 1400–1402 in the Iranian calendar) in the Jishabad rangeland site of Tarom County. For this purpose, a systematic sampling design was applied, in which four main plots (each 10×10 m) were randomly selected within a one-hectare study site. In each main plot, four subplots of 1×1 m were established. Field measurements were conducted during the peak growth season (May–June) over three consecutive years. In each subplot, data on species composition, life form, percentage cover of vegetation, litter, moss, bare soil, gravels, and erosion intensity were recorded. Species identification was conducted using reliable floristic references for Iranian flora. Diversity indices including richness (Margalef and Menhinick), evenness (Pielou), and diversity (Shannon–Wiener and Simpson) were calculated and analyzed using appropriate parametric and non-parametric statistical methods. The results revealed that biodiversity indices varied significantly across the study years. Results showed significant increases in biodiversity indices over the study period (2021–2023): the mean number of species per subplot rose from 5.69 in 2021 to 7.75 in 2023 (P < 0.01); the Shannon–Wiener index increased from 1.62 to 1.96, and the Simpson index from 0.16 to 0.83 These changes, accompanied by a 10% reduction in bare soil cover and increased perennial plant frequency, were likely driven by grazing management, natural exclosure, and favorable climatic conditions.

Highlights

Assadi, M., Maassoumi, A. A., Khatamsaz, M., & Mozaffarian, V. (Eds.). (1988–2018). Flora of Iran. Research Institute of Forests and Rangelands, Tehran, Iran. (In Persian).

Aghajanlou, F., & Akbarzadeh, P. (2025). Assessment of changes in biodiversity indices and plant species structure over a three-year period in Shirmisheh site, Tarom County. Journal of Renewable Natural Resources Research, 16(1), 85–105. https://doi.org/10.71916/jrnr.2025.1216021 (In Persian).

Aghajanlou, F., & Akbarzadeh, P. (2026). Assessment of vegetation cover changes and floristic structure in the Shir Misheh forest stand, Tarom County. Plant and Ecosystem Conservation, 13(27), 13. http://pec.gonbad.ac.ir/article-1-1023-fa.html (In Persian).

Akbarzadeh, P., nikoo, S., & Akbarzadeh, M. (2025). Investigating Spatial and Temporal Changes in Vegetation via Remote Sensing Indicators and Revealing Their Trends in The Central Desert of Iran. Applied Environmental Research, 47(3). https://doi.org/10.35762/AER.2025024

Akbarzadeh, P., & Niko, S. (2022). Investigating the effect of regional development as land-use change on groundwater table level: A case study of Damghan watershed. Geography and Environmental Sustainability, 12(3), 1–21. https://doi.org/10.22126/ges.2022.7594.2512(In Persian).

Azarnivand, H., & Zare Chahouki, M. A. (2011). Rangeland Ecology. Tehran University Press. (In Persian).

Banihashemi, A., Tahmasabi, P., & Asadi, A. (2017). The effect of different grazing managements on the functional traits of plants in the semi-steppe area of Krasnak, Chaharmahal and Bakhtiari province. Journal of Range and Desert Research, 25(3), 547–561. https://doi.org/10.22092/ijrdr.2018.117806(In Persian).

Che, J., Ye, M., He, Q., Zeng, G., Li, M., Chen, W., Pan, X., Qian, J., & Lv, Y. (2025). Elevation gradient effects on grassland species diversity and phylogenetic in the Two-River Source Forest Region of the Altai Mountains, Xinjiang, China. Frontiers in Plant Science, 16, 1487582. https://doi.org/10.3389/fpls.2025.1487582

Dinarvand, M., Fayaz, M., Behnamfar, K., Khaksarian, F., Yasreby, B., & Arami, S. A. (2021). An assessment of species diversity and vegetation richness indices in two dust centers of Khuzestan province. The Iranian Journal of Biology, 9(4), 73–87. http://dx.doi.org/10.47176/ijae.9.4.12781 (In Persian).

Dornelas, M., et al. (2014). Assemblage time series reveal biodiversity change but not systematic loss. Science, 344(6181), 296-299. https://doi.org/10.1126/science.1248484

Ejtehadi, H., Sepehri, A., & Akefi, H. R. (2008). Methods of Measuring Biodiversity. Ferdowsi University of Mashhad Publications. (In Persian).

Fakhar Izadi, N., & Keshtkar, H. (2020). Investigating the effects of distribution patterns on ecological indices of plant species in a simulated environment. Desert. 25(2): 201-211. 10.22059/jdesert.2020.79257

Fakhimi, E., Shirmardi, H. A., & Asadi, S. M. (2023). Vegetation indices and species diversity monitoring under exclosure management in semi-steppe rangelands: A case study of Ghalehgharak Rangelands, Chaharmahal and Bakhtiari Province. Journal of Rangeland, 17(3), 382–397. https://dor.isc.ac/dor/20.1001.1.20080891.1402.17.3.4.7 (In Persian).

Ghorbani, A., Dadjou, F., Moameri, M., Fekri, A., Sattarian, A., Cheraghi, M., Azarnivand, H., & Naseri, A. (2021). Effect of grazing exclusion on soil and vegetation characteristics in desert steppe rangelands: A case study from north-western Iran. Arid Land Research and Management, 35(1), 63–85. https://doi.org/10.1080/15324982.2020.1850542

Ghorbanpour Delivand, M., Tatian, M., Tamartash, R., Gonzalez Alday, J., & Alavi, S. J. (2023). Scale-dependent changes in plant species richness and diversity indicators: A case study in the plain rangelands of Northern Iran (Khomam, Gilan). Journal of Rangeland, 17(3), 398–410. https://dor.isc.ac/dor/20.1001.1.20080891.1402.17.3.5.8 (In Persian).

Gurevitch, J., et al. (2018). Sampling scale and biodiversity patterns. Ecology Letters, 21(2), 234-250. https://doi.org/10.1111/ele.12864

Heydarian Aghakhani, M., Naqipour Borj, A. S., & Nasri, M. (2011). The effect of exclosure on vegetation cover and soil chemical properties in C. Sub Bojnord pastures. Journal of Renewable Natural Resources Research, 1(2), 14–27. (In Persian).

Hill, M. O. (1973). Diversity and evenness: A unifying notation and its consequences. Journal of Ecology, 54(2), 427–432. https://doi.org/10.2307/2259232

Kawada, K., Suzuki, K., Suganuma, H., Smaoui, A., & Isoda, H. (2012). Plant biodiversity in the semi-arid zone of Tunisia. Journal of Arid Land Studies, 22(1), 83–86.

Khademolhosseini, Z. (2010). Comparison of numerical plant species diversity indices in three different grazing intensities (Case study: Gardanch Zambouri-Arsanjan). Rangelands, 4(1), 104–111. (In Persian).

Magurran, A. E. (2004). Measuring Biological Diversity. Blackwell Publishing.

McCann, K. S. (2000). The diversity–stability debate. Nature, 405, 228–233. https://doi.org/10.1038/35012234

Mesdaghi, M. (2018). Plant Ecology. Mashhad: Jahad Daneshgahi Mashhad Press. (In Persian)

Nikbakht, M., Farzam, M., Khajeh Hosseini, M., & Ejtehadi, H. (2017). Study of plant species biodiversity in arid rangelands of Iran. Iranian Journal of Range and Desert Research, 23(1), 55–67. (In Persian).

Omidipour, R., Erfanzadeh, R., & Faramarzi, M. (2017). Investigating the effect of livestock grazing on plant diversity components in the semi-arid rangelands of Iran. Journal of Rangeland and Watershed Management, 70(3), 723–734. https://doi.org/10.22059/jrwm.2017.113281.803 (In Persian).

Rostampour, M. (2024). Evaluation of the accuracy of the numeric indices of the biodiversity calculated based on the quantitative characteristics of vegetation in the rangelands of Darmian-Sarabisheh Protected Area, South Khorasan. Journal of Range and Watershed Management, 77(4), 419–432. 419-432. doi: 10.22059/jrwm.2024.373062.1749 (In Persian).

Tamartash, R. (2012). Evaluation of rangeland condition based on plant indices in Lasem Haraz meadows. Journal of Range and Desert Research, 19(2), 221–232. (In Persian).

Vellend, M., Baeten, L., Myers-Smith, I. H., Elmendorf, S. C., Beauséjour, R., Brown, C. D., De Frenne, P., Verheyen, K., & Wipf, S. (2013). Global meta-analysis reveals no net change in local-scale plant biodiversity over time. Proceedings of the National Academy of Sciences, 110(48), 19456–19459. https://doi.org/10.1073/pnas.1312779110

Whittaker, R. H. (1972). Evolution and Measurement of Species Diversity. Taxon, 21(2-3), 213-251. https://doi.org/10.2307/1218190

Wilson, S. D., & Tilman, D. (2002). Quadratic variation in old-field species richness along gradients of disturbance and nitrogen. Journal of Ecology, 83(4), 450–479. https://doi.org/10.1890/0012-9658(2002)083%5B0492:QVIOFS%5D2.0.CO;2

Zare Chahouki, M. A., Hosseini, M., & Tavili, A. (2013). Investigation of factors affecting species diversity changes in the middle Taleghan rangelands. Plant Research Journal, 4(2), 234–245. (In Persian)

Keywords

Diversity and Richness Indices
Exclosure Management
Long-term Vegetation Monitoring
Plant Biodiversity
Iranian–Turanian Rangeland
Journal of Range and Watershed Managment
Volume 79, Issue 2
Summer 2026
Pages 147-168

  • Receive Date 19 September 2025
  • Revise Date 24 October 2025
  • Accept Date 27 October 2025
  • Publish Date 01 July 2026

Home

Guide for Authors

Submit Manuscript

Contact Us