Rangeland Ecology & Management

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Livestock Browsing, Not Water Limitations, Contributes to Recruitment Failure of Dobera glabra in Semiarid Ethiopia
Author
Tsegaye, Diress
Moe, Stein R.
Haile, Mitiku
Publisher
Society for Range Management
Publication Year
2009-11-01
Body

The study used nursery and field experiments to investigate why recruitment of Dobera glabra (Forssk) Poir., a native food source for both humans and livestock, often fails in the semiarid rangelands of Afar, Ethiopia. We hypothesized that soil water limitations and browsing by livestock would be the primary mechanisms accounting for the failure of natural regeneration. We used three sets of experiments—1) seedling performance in response to shade and watering in a nursery, 2) field regeneration with and without browsing, and 3) regeneration beneath trees with and without browsing—to examine regeneration success. Seedlings were established in plots from seeds sown directly into the soil for nursery and field experiments, but natural germination occurred beneath trees. Survival and relative growth rates (RGR) were used to monitor seedling performance. Seedlings that received neither shade nor watering treatments had lower seedling survival (53 +/- 15%) as compared with other treatment combinations. Highest seedling survival was recorded under shade and 1 d watering wk-1 treatment combinations (92 +/- 1%). However, shade treatments had a minimal increase on seedling RGR. Water limitation is not a crucial limiting factor for D. glabra recruitment, as 53% of the seedlings survived without both shade and supplemental water for 1 yr. Field experiments, however, demonstrated that browsing greatly reduced seedling survival (below 15%) and suppressed growth of surviving seedlings, suggesting that browsing is the major factor preventing natural recruitment. Natural recruitment of D. glabra is unlikely with the existing continuous and intensive grazing/browsing in Afar rangelands, where the mobility of pastoralists is restricted. We suggest that planting nursery-raised seedlings in home gardens of settled pastoralists and establishment of grazing reserves in some key range sites that contain D. glabra could help offset the recruitment failure of native food species D. glabra in Afar rangelands.  The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information. Migrated from OJS platform August 2020

Language
en
Resource Type
Text
Document Type
Journal Issue/Article
Digital Object Identifier (DOI)
10.2111/08-219.1
Additional Information
Tsegaye, D., Moe, S. R., & Haile, M. (2009). Livestock browsing, not water limitations, contributes to recruitment failure of Dobera glabra in semiarid Ethiopia. Rangeland Ecology & Management, 62(6), 540-549.
IISN
0022-409X
OAI Identifier
oai:repository.arizona.edu:10150/643060
Journal Volume
62
Journal Number
6
Journal Pages
540-549
Journal Name
Rangeland Ecology & Management
Keywords
Afar pastoralists
herbivory
seedling survival
tree regeneration