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Effect of Elevation on the Density and Species Composition of Encroacher Woody Plants in Borana Rangeland, Southern Ethiopia

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Abstract

Woody plant encroachments are major concerns across the grasslands biome, while the patterns of individual species existence at a landscape level can be limited locally and regionally. The paper assesses the species composition, community structure, and density of individual and combined encroacher woody species in terms of tree equivalent per hectare (TE ha−1) within five different height classes at four elevation levels in Borana arid thorn bush savanna grasslands in Southern Ethiopia. At each elevation class, a grid of 20 × 20 m main plot was placed, and samples were collected randomly from three 100 m2 sub-plot within the main plot. Using a single-factor analysis of variance, the effects of four elevation classes were considered on encroacher woody plant species composition, total, and individual density (TE ha−1) within height classes. A total of 22 encroacher woody plant species composition were identified. The identified woody plants are seemingly a threat to the Borana rangelands of Southern Ethiopia with various patterns of distribution and density (TE ha−1) among the different elevation levels. Of the identified species, Acacia reficiens had the highest density (1052.22 ± 265.34 TE ha−1) at elevation level II. The most important encroaching species in each elevation level was varied considerably, while the combined woody plants density (TE ha−1) within height classes across elevation levels showed minimal variations. This suggests that the management of a specific ecological site might require greater focus in terms of the functional traits of individual woody species composition, density coverage within height classes, and community structure. Hence, identifying the patterns, distribution, and density of encroaching woody species is crucial for the control of key encroacher woody species at a landscape level.

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Data availability

Data for this manuscript were collected through field vegetation sampling and observation in the field.

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Acknowledgements

We thank the local community and staff members of Pastoral Development Office of Dubluk, Dirre, and Dillo districts for their kind support during data collection and the University of Chinese Academy of Sciences, Beijing, and National Engineering Technology Research Center for Desert-Oasis Ecological Construction, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang, China.

Funding

This study received financial support from National Key Research and Development Program of China-Joint Research on Technology to Combat Desertification for African Countries of the “Great Green Wall” (No. 2018YFE106000); Projects of International cooperation and Exchanges NSFC (Grant No. 41861144020); Science and Technology Partnership Program, Ministry of Science and Technology of China (Grant No. KY201702010).

Author Contributions

Conceptualization and methodology: ZB and AA. Formal analysis and investigation: ZB. Writing (original draft preparation): ZB. Writing (review and editing): ZB, AA, YW and YY. Resources and Supervision: XX. All authors read and approved the final manuscript.

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Authors and Affiliations

  1. National Engineering Technology Research Center for Desert-Oasis Ecological Construction, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Beijing Road, Urumqi, 830011, Xinjiang, China

    Zinabu Bora, Yongdong Wang, Xinwen Xu & Yuan You

  2. University of Chinese Academy of Sciences, 100049, Beijing, China

    Zinabu Bora

  3. Oromia Pastoral Area Development Coordination Commission, P. Box 20120, Addis Ababa, Ethiopia

    Zinabu Bora

  4. Department of Range and Forest Resources, Faculty of Natural Resources, Botswana University of Agriculture and Natural Resources, Private Bag 0027, Gaborone, Botswana

    Ayana Angassa

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  1. Zinabu Bora
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  2. Ayana Angassa
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  3. Yongdong Wang
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  4. Xinwen Xu
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  5. Yuan You
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Correspondence to Zinabu Bora or Yongdong Wang.

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Bora, Z., Angassa, A., Wang, Y. et al. Effect of Elevation on the Density and Species Composition of Encroacher Woody Plants in Borana Rangeland, Southern Ethiopia. Environmental Management 67, 1075–1087 (2021). https://doi.org/10.1007/s00267-021-01458-x

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  • DOI: https://doi.org/10.1007/s00267-021-01458-x

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