The protective and sheltering role of shrub plants on the stability of the Astragalus ecosystems

Document Type : Research Paper

Authors

1 Assistant Professor, Khorasan-e-razavi Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Mashhad, Iran,

2 Assistant Professor, Khorasan-e-Razavi Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Mashhad. Iran

3 Associate Professor, Rangeland Research Division, Research Institute of Forests and Rangelands, Agricultural Research Education and Extension Organization (AREEO), Tehran, Iran

4 Researcher, Research and Education Center for Agriculture and Natural Resources of Khorasan Razavi Province, Organization for Research, Education and Extension of Agriculture, Mashhad, Iran

Abstract

Background and objectives: Shrub plants, acting as living shelters, significantly influence species diversity and the stability of grazed ecosystems. Removing shrubs from rangeland plant communities without protective measures can destabilize rangeland habitats. This study aimed to investigate the protective and sheltering roles of Astragalus heratensis Bunge. and Acanthophyllum glandulosum Bunge ex Boiss. on the stability of Astragalus habitats in the eastern highlands of Iran.
Methodology: The study was conducted in the Astragalus habitats of Torbat-e-Heydarieh, representing the eastern highlands. Species type and density were measured in 50 plots (2 m²) placed 10 meters apart along five 100-meter transects. Along each transect, 10 plant bases of each species (A. heratensis and A. glandulosum) with crowns intersecting the transect were selected. Height, major and minor diameters, and canopy cover were measured. Within microplots (0.25 m²) placed under the canopy of each shrub, crown cover percentage and species density were recorded. Simultaneously, at a distance of less than 2 meters from each plant base on the opposite side of the transect, a similar microplot (0.25 m²) was established in open areas to measure crown cover and species density. Species diversity indices were calculated for both under-canopy and open areas. Independent samples t-tests were used to compare species diversity between these areas.
Results: Based on the results, Astragalus heratensis Bunge. has a greater protective role for sub-shrub species than Acantholimon glandulosum Bunge ex Boiss., primarily due to its superior height and canopy cover. The percentage of canopy cover, density, and species diversity indices under its crown are higher than those under A. glandulosum. Additionally, the vegetation characteristics and species diversity under the canopy of shrub plants are greater than in the open spaces between them. Most species that exhibit high density under the canopy of A. heratensis and A. glandulosum are rarely observed in open areas. This phenomenon is attributed to the favorable microhabitat conditions that shrub plants create for annual species. No significant difference was observed in the protective and sheltering roles of A. heratensis and A. glandulosum in terms of outdoor biomass production. However, the biomass production of sub-shrubs under A. heratensis was 35% higher than under A. glandulosum.
Conclusion: Shrub plants, functioning as living shelters, protect species under their canopy from direct livestock grazing and create a refuge for palatable species that are sensitive to grazing pressure. Additionally, they provide favorable conditions for the germination, growth, survival, and production of edible species. In general, due to their role in sheltering and supporting annual species, shrub plants play a crucial role in the diversity, conservation, and management of grazed ecosystems. Their protective function can be utilized to enhance and restore rangeland vegetation.

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References

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History

  • Receive Date: 08 June 2024
  • Revise Date: 06 August 2024
  • Accept Date: 11 November 2024

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