Article

Kide M. Gebremedihin, Mekelle University, Ethiopia
Emiru Birhane, Mekelle University, Ethiopia; e-mail: emiru.birhane@mu.edu.et, emiru.birhane.hizikiaz@nmbu.edu.et
Tewodros Tadesse, Mekelle University, Ethiopia
Hailemariam Gbrewahid, Mekelle University, Ethiopia

Gebremedihin K.M., Birhane E., Tadesse T., Gbrewahid H. 2018. Restoration of degraded drylands through exclosures enhancing woody species diversity and soil nutrients in the highlands of Tigray, Northern Ethiopia. Nature Conservation Research 3(1): 1–20. https://dx.doi.org/10.24189/ncr.2018.001

Exclusion of grazing animals and tree plantations were among the methods used for the rehabilitation of degraded lands in tropical semiarid areas. Exclosures can foster secondary forest succession by improving soil conditions, attracting seed-dispersal agents and modifying microclimate for understory growth. This paper compares the woody species diversity and soil chemical properties under exclosure with increasing age and grazing land at different slope positions. The study has been conducted in northern Ethiopia from 12 exclosure sites paired each with adjacent grazing land with four treatments replicated three times. In the entire study 216 plots were examined of which 108 were in exclosures and 108 in communal grazing lands.There were four age classes and three slope positions in each of the landuses. Vegetation data were collected using plots measuring 100 m². Soils for physicochemical properties were collected from the four corners and center of 5 × 5m plots which was inside the 10 × 10m plot. A total of 61 woody plant species belonging to 41 families were recorded. Diversity and species richness were higher in the exclosures than in grazing lands. Among exclosures these parameters were higher in exclosures older than 30 years and at the foot of the slope. Grazing lands, the youngest exclosures and upper elevation gradient recorded lower values. Chemical soil properties were significantly higher in the exclosures, among them in the oldest exclosures and at foot elevation (except for P) than these were in the grazing land, the youngest exclosures and upper parts of slopes respectively. Exclosures are instrumental to improve the woody species diversity and soil chemical properties in the drylands.

chemical soil properties, exclosure, slope position, woody diversity

Received: 21.08.2017

Ajorlo M., Abdullah R., Hanif A.H.M., Halim R.A., Yusoff M.K. 2011. Impacts of livestock grazing on selected soil chemical properties in intensively managed pastures of Peninsular Malaysia. Pertanika Journal of Tropical Agricultural Science 34: 109–121.
Bekele-Tesemma A. 2007. Useful trees and shrubs of Ethiopia: Identification, Propagation and Management for 17 Agroclimatic Zones. Nairobi: RELMA. 550 p.
Berry L. 2003. Land degradation in Ethiopia: Its extent and impact. In: L. Berry, J. Olson, D. Campbell (Eds.): Assessing the extent, cost and impact of land degradation at the national level: Findings and lessons learned from seven pilot case studies.Washingon, DC: World Bank. P. 29–51.
Babulo B., Muys B., Nega F., Tollens E., Nyssen J., Deckers J., Mathijs E. 2008. Household livelihood strategies and forest dependence in the highlands of Tigray, Northern Ethiopia. Agricultural Systems 98: 147–155. DOI: 10.1016/j.agsy.2008.06.001
Birhane E., Teketay D., Barklund P. 2006. Actual and potential contribution of exclosures to enhance biodiversity of woody species in the drylands of Eastern Tigray. Journal of the Drylands 1(2): 134–147.
Birhane E. 2002. Actual and Potential Contributions of Enclosures to Enhance Biodiversity in Drylands of Eastern Tigray, with Particular Emphasis on Woody Plants. Upsala, Sweden: Swedish University of Agricultural Sciences. 63 p.
Bremmer J.M., Mulvaney C.S. 1982. Nitrogen total. In: A.L. Page (Ed.): Methods of Soil Analysis, Part 2 Chemical and Microbiological Properties, №9. Madison, WI, USA: ASA Monograph. P. 595–624.
Cheng J., Wu G.L., Zhao L.P., Li Y., Li W., Cheng J.M. 2011. Cumulative effects of 20-year exclusion of livestock grazing on above and belowground biomass of typical steppe communities in arid areas of the Loess Plateau, China. Plant, Soil and Environment 57: 40–44.
Dejenie A. 2011. Impact of Resettlement on Woody Plant Species and Local Livelihood: The Case of Guraferda Woreda in Bench Maji Zone, South Western, Ethiopia. PhD Thesis. Addis Ababa, Ethiopia. 98 p.
Descheemaeker K., Muys B., Nyssen J., Poesen J., Raes D., Haile M., Deckers J. 2006. Litter production and organic matter accumulation in exclosures of the Tigray highlands, Ethiopia. Forest Ecology and Management 233: 21–25. DOI: 10.1016/j.foreco.2006.05.061
Edwards S., Tadesse M., Hedberg I. (Eds.). 1995. Flora of Ethiopia and Eritrea. Vol. 2, Part 2: Canellaceae to Euphorbiaceae. Ethiopia: Addis Ababa University Press. 456 p.
Edwards E., Tadesse M., Demissew S., Hedberg I. (Eds.). 2000. Flora of Ethiopia & Eritrea. Vol. 2, Part 1: Magnoliaceae to Flacourtiaceae. Ethiopia: Addis Ababa University Press. 532 p.
EMA. 2014. Ethiopian Meteorological service agency Report of Ethiopian meteorological service agency from the respective areas. Addis Ababa, Ethiopia.
FAO. 2007. Enhancing Stakeholder Participation in National Forest Programmes. Rome, Italy: Forestry Policy Brief.
Gee G.W., Bauder J.W. 1982. Particle size analysis. In: A. Klute (Ed.): Methods of Soil Analysis, Part 1 Physical and Mineralogical Methods, №9. Madison, WI, USA: ASA Monograph. P. 383–411.
Getachew M. 2014. Vegetation Dynamics of Area Enclosure Practices: A Case of Gonder Zuria District, Amhara Region, Ethiopia. Journal of Natural Sciences Research 4(7): 75–82.
Girmay G., Singh B.R., Nyssen J., Borrosen T. 2009. Runoff and sedimentassociated nutrient losses under different land uses in Tigray, Northern Ethiopia. Journal of Hydrology 376: 70–80. DOI: 10.1016/j.jhydrol.2009.07.066
Haileslassie A., Priess J., Veldkamp E., Teketay D., Lensschen J.P. 2005. Assessment of soil nutrient depletion and its spatial variability on smallholders' mixed farming systems in Ethiopia using partial versus full nutrient balances. Agriculture Ecosystem and Environment 108(1): 1–16. DOI: 10.1016/j.agee.2004.12.010
Hedberg I. & Edwards S. (Eds). 1989. Flora of Ethiopia. Vol. 3: Pittosporaceae to Araliaceae. Ethiopia: Addis Ababa University Press. 670 p.
Hedberg I., Edwards S., Nemomissa S. (Eds.). 2003. Flora of Ethiopia and Eritrea. Vol. 4, Part 1: Apiaceae to Dipsacaceae. Ethiopia: Addis Ababa University Press. 352 p.
Hiernaux P., Bielders C.L., Valentin C., Bationo A., Fernandez-Rivera S. 1999. Effects of livestock grazing on physical and chemical properties of sandy soils in Sahelian rangelands. Journal of Arid Environments 41: 231–245. DOI: 10.1006/jare.1998.0475
Hurni H., Kebede T., Gete Z. 2005. The implications of changes in population, land use, and land management for surface runoff in the Upper Nile Basin area of Ethiopia. Mountain Research and Development 25: 145–149. DOI: 10.1659/0276-4741(2005)025[0147:TIOCIP]2.0.CO;2
Jama B., Zeila A. 2005. Agroforestry in the drylands of eastern Africa: a call to action. ICRAF Working Paper – №1. Nairobi: World Agroforestry Centre. 29 p.
Jeddi K., Chaieb M. 2010. Changes in soil properties and vegetation following livestock grazing exclusion in degraded arid environments of South Tunisia. Flora – Morphology, Distribution, Functional Ecology of Plants 205: 184–189. DOI: 10.1016/j.flora.2009.03.002
Lemenih M., Kassa H. 2014. Re-Greening Ethiopia: History, Challenges and Lessons. Forests 5: 1896–1909. DOI: 10.3390/f5081896
Magurran A.E. 2004. Measuring biological diversity. London: Blackwell Publishing. 256 p.
Mekuria W. 2010. Effectiveness of Exclosures to Restore Ecosystem Carbon Stock and Vegetation in the Highlands of Tigray, Northern Ethiopia. PhD thesis. Göttingen: University of Göttingen.
Mekuria W. 2013. Changes in Regulating Ecosystem Services following establishing Exclosures on Communal Grazing lands in Ethiopia. Journal of Ecosystems 2013 (2013): 1–12. DOI: 10.1155/2013/860736
Mekuria W., Aynekulu E. 2011. Exclosure land management for restoration of the soil in degraded communal grazing lands in northern Ethiopia. Land Degradation and Development 246(6): 528–538. DOI: 10.1002/ldr.1146
Mekuria W., Edzo V., Haile M., Gebrehiwot K., Bart M., Jan N. 2009. Effectiveness of exclosures to control soil erosion and local community perception on soil erosion in Tigray, Ethiopia. African Journal of Agricultural Research 4(4): 365–377.
Mekuria W., Veldkamp E., Mitiku H., Nyssem J., Muys B., Kindeya G. 2007. Effectiveness of exclosures to restore degraded soils as a result of overgrazing in Tigray, Ethiopia. Journal of Arid Environments 69: 270–284. DOI: 10.1016/j.jaridenv.2006.10.009
Mekonen K., Tesfahunegn G.B. 2011. Impact assessment of soil and water conservation measures at Medego watershed in Tigray, northern Ethiopia. Maejo International Journal of Science and Technology 5(3): 312–330.
Mengistu T., Demel T., Håkan H., Yonas Y. 2005. The Role of Communities in Closed Area Management in Ethiopia. Mountain Research and Development 25(1): 44–45. DOI: 10.1659/0276-4741(2005)025[0044:TROCIC]2.0.CO;2
Minal T., Anil V. 2012. Mycorrhizae at polluted site of western rajasthan. International Journal of Plant, Animal and Environmental Sciences 2(4): 325–487.
Molla M., Kindeya G., Birhane E., Tewoldeberhan S. 2009. Regeneration, Density and Diversity of Woody Vegetation in Awash National Park, Ethiopia. Journal of the Drylands 2(2): 101–109.
Nedessa B., Ali J., Nyborg I. 2005. Exploring Ecological and Socio-Economic Issues for the Improvement of Area Enclosure Management a Case Study from Ethiopia. Drylands Coordination Group Report №38. Oslo: Mail Boxes ETC. 55 p.
Olsen S.R., Sommers L.E. 1982. Phosphorus. In: A.L. Page (Ed.): Methods of Soil Analysis, Part 2 Chemical and Microbiological Properties, №9. Madison, WI, USA: ASA Monograph. P. 403–430.
Reusing M., Schneider T., Ammer U. 2000. Modelling soil loss rates in the Ethiopian highlands by integration of high resolution MOMS-02/D2-stereo data in a GIS. Journal of Remote Sensing 21: 1885–1896.
Seyoum Y., Birhane E., Kassa H., Hagazi N., Esmael N., Mengistu T. 2015. Enhancing the role of the forestry sector in Ethiopia: strategy for scaling up effective forest management practices in Tigray Region with emphasis on area exclosures. Addis Ababa: CIFOR Ethiopia Office. 62 p.
Solomon D., Fritzche F., Lehmann J., Tekalign M., Zech W. 2002. Soil organic matter dynamics in the sub humid agro-ecosystems of the Ethiopian highlands: evidence from natural ¹³C abundance and particle-size fraction. Soil Science Society of America Journal 66: 969–978.
Sonneveld B.G.J.S., Keyzer M.A. 2002. Land under pressure: soil conservation concerns and opportunities for Ethiopia. Land Degradation and Development 14(5): 5–23. DOI: 10.1002/ldr.503
Tadesse G. 2001. Land Degradation: A Challenge to Ethiopia. Journal of Environmental Management 27(6): 815–824. DOI: 10.1007/s002670010
Tadesse G., Penden D. 2002. Livestock grazing impact on vegetation, soil and hydrology in a tropical highland watershed. Proceedings of MoWR/EARO/IWMI/ILRI International Workshop (ILRI, Addis Ababa, Ethiopia 2–4 December, 2002). Addis Ababa. P. 87–97.
Van Ranst E., Verloo M., Demeyer A., Pauwels J.M. 1999. Manual for the soil chemistry and fertility laboratory: analytical methods for soils and plants, equipments and management of consumables. Belgium: University of Gent. 243 p.
Wairore J.N.U., Mureithi S.M., Wasonga O.V., Nyberg G. 2015. Characterization of enclosure management regimes and factors influencing their choice among agropastoralists in North-Western Kenya. Pastoralism 5: 1–14. DOI: 10.1186/s13570-015-0036-7
World Bank. 2001. African Development Indicators. Washington D.C. 392 p.
WRB. 2006. World reference base for soil resources. 2^nd ed. World Soil Resources Reports №103. Rome: FAO. 128 p.
Yami M., Gebrehiwet K., Stein M., Mekuria W. 2006. Impact of Area Enclosures on Density and Diversity of Large Wild Mammals: The Case of May Ba'ati, Douga Tembien District, Central Tigray, Ethiopia. East African Journal of Sciences 1(1): 55–68.
Yayneshet T., Eik L.O., Moe S.R. 2009. The effects of exclosures in restoring degraded semi-arid vegetation in communal grazing lands in northern Ethiopia. Journal of Arid Environments 73: 542–549. DOI: 10.1016/j.jaridenv.2008.12.002
Yirdaw E. 2001. Diversity of naturally-regenerated native woody species in forest plantations in the Ethiopian highlands. New Forests 22: 159–177. DOI: 10.1023/A:1015629327039