Conservation Status of Vegetation in the Dryland of Northwestern Nigeria
Vegetation contributes to human and ecosystem existence is overwhelming. It provides food, raw materials and oxygen, as well as in exchange of water, energy, and nutrients. The study assessed conservation status of fifty plant species that were encountered in nineteen study locations in the dryland of northwestern Nigeria. Quantitative data for the assessment was obtained through quadrat sampling. The sampling was done at 100 x 100m2 quadrat in nineteen locations identified on a line drawn diagonally along a north–south transect; which cover the major bioclimatic gradient of the study area. Relative densities of plants are used to categorise the fifty plants into five conservation statuses namely critically endangered, endangered, vulnerable, threatened and stable categories as found in IUCN Red lists version 3.1. Result show that the stable group (6%) consists of Piliostigma reticulatum (RD=21.02%), Guiera senegalensis (RD=12.40%) and Azadirachta indica (RD=10.32%) in order of decreasing relative densities. Vulnerable category (8%) consists of Fadherbia albida (RD=9.79%), Ziziphus mauritania (RD=8.16%), in decreasing order of relative densities. Threatened group (24%) consist of fourteen species. Notable species are Balanite aegyptiaca (RD=4.26%), Adansonia digitata (RD=2.47%), Lannea acida (RD=2.00%) and Acacia seyal (RD=1.60%) in decreasing order of relative density. Endangered group (44%) consist of twenty two species. Notable members are Vitex doniana (RD=0.14%), Anogiessus leocarpus (RD=0.19%), Tamarindus indica (0.38%) in order of decreasing relative density. Critically endangered group (18%) with nine plants comprises of Albizia chivalieri (RD=0.01%), Butyresopermum parkii (RD=0.09%), Proposis africana (RD=0.09%), and Ficus iteophylla (RD=0.09%) among others. The study concludes that there are lot of species in vulnerable, endangered and threatened categories. The study recommends that conservation status assessments and monitoring should be conducted regularly using local parameters so as to provide up to date information for the effective management of vegetation in the country and particularly the dryland of northern Nigeria.
Conservation Status, Vegetation, Dryland, Northwestern Nigeria
Borokini, T. I. (2013). A Systematic Compilation of IUCN Red-listed Threatened Plant Species in Nigeria. International Journal of Environmental Sciences, Vol. 3(3):104-133.
Briggs, J. and Leigh, J. (1996). Rare or Threatened Australian Plants. CSIRO Publications, Melbourne.
Chuai, X. W., Huang, X. J., Wang, W. J. and Bao, G. (2013). NDVI, temperature and precipitation changes and their relationships with different vegetation types during 1998–2007 in Inner Mongolia, China. International Journal of Climatology, vol. 33(7):1696–1706.
David, M. (2008). 118/119 Biodiversity and Tropical Forest Assessment for Nigeria. USDA Forest Service/International Forestry for USAID/Bureau for Africa. Washington, DC.
Edward, C. W. (1998). Threats to biodiversity. In: Brown, L.: The elimination of species- rich tropical forests and other habitats is driving many plant and animal species to extinction. Washington, DC.
Eric, F. L., Helmut, J. G. and Erika, L. (2003). Dynamics of land-use and land-cover Change in tropical regions. Annu. Rev. Environ. Resour., 28:205-41.
Federal Government of Nigeria (2006). Approved National Forest Policy 2006. Federal Ministry of Environment of Nigeria, Abuja
Fewster, R. M., Laake, J. L. and Buckland, S. T. (2005). Line transect sampling in small and large regions. Biometrics, 61:856-859.
Gbile, Z. O., Ola-Adams, B. A. and Soladoye, M. O. (1978). Endangered species of the Nigerian Flora. Nigerian Journal of Forestry, 8(1, 2).
Guinko, S. (1984). Vegetation de la Haute-Volta. "Docteur en Science Naturelle" thesis, Université de Bordeaux.
International Union for Conservation of Nature, IUCN (2009). IUCN Red List of Threatened Species. Version 2009.2, Gland, Switzerland.
International Union for Conservation of Nature, IUCN (2012). IUCN Red List Categories and Criteria: Version 3.1. Second edition. Gland, Switzerland and Cambridge, IUCN, UK.
Kindt, R. and Coe, R. (2005). Tree Diversity Analysis. A manual and software for common statistical methods for ecological and biodiversity studies. World Agroforestry Centre (ICRAF), Nairobi.
Li, X. H., Shi, Q. D., Chang, S. L., et al. (2008). Change of NDVI based on NOAA image in northwest arid area of China in 1981−2001. Arid Land Geography, 31(6): 940−945.
Lykke, A. N., Fog, B. and Madsen, J. E. (1999). Woody Vegetation changes in the Sahel of Burkina Faso assessed by means of local knowledge, aerial photos, and botanical investigations. GeografiskTidsskrift, Danish Journal of Geography Special Issue, 2: 57-68.
Mace, G. M. and Lande, R. (1991). Assessing Extinction Threats: Toward a Re-evaluation of IUCN Threatened Species Categories. Conservation Biology, 5:2
Miller, R. M. (2013). Threatened Species: Classification Systems and their Applications. In: Levin, S. A. (Ed.) Encyclopedia of Biodiversity (Second Edition). Elsevier, Massachusetts, USA.
Mortimore, M. and Adams, W. (1999). Working the Sahel: Environment and society in Northern Nigeria. Routledge, London.
Onyekwelu, J. C., Mosandl, R. and Stimm, B. (2007). Tree species diversity and soil status of two natural forest ecosystems in lowland humid tropical rainforest region of Nigeria. Conference on International Agricultural Research for Development. University of Kassel-Witzenhausen and University of Göttingen, October 9-11, 2007.
Piao, S. and Fang, J. (2013). Seasonal changes in vegetation activity in response to climate changes in China between 1982 and 1999. Acta Geographica Sinica, vol. 58(1): 119–125.
Possingham, H. and Andelman, S. (2002). Limits to the use of threatened species lists. Trends Ecol. Evol., vol. 17:11:503–507.
Rajendran, P., Thirumurthi, S. and Kanna, S. U. (2001). Seed dispersal by Avian fauna in forest ecosystem. Advances in Horticulture and Forestry, 8:265-273.
Secretariat of the Convention on Biological Diversity (2009). The Convention on Biological Diversity Plant Conservation Report: A Review of Progress in Implementing the Global Strategy of Plant Conservation (GSPC), Montreal, Canada
Secretariat of the Convention on Biological Diversity (2010). Global Biodiversity Outlook 3. Convention on Biological Diversity, Montreal, Canada
Singh, J. S. (2002). The Biodiversity Crisis: A Multifaceted Review. Current Science, 82:638–647.
Stem, C., Margolius, R., Salafsky, N. and Brown, M. (2005). Monitoring and Evaluation in Conservation: a Review of Trends and Approaches. Conservation Biology, 19(2):295-309.
Stuart, S. N., Wilson, E. O., McNeely, J. A., Mittermeier, R. A. and Rodriguez, J. P. (2010). The Barometer of Life. Science, vol. 328:80.
Sun, H. Y., Wang, C. Y. and Niu, Z. et al. (1998). Analysis of the vegetation cover change and the relationship between NDVI and environmental factors by using NOAA time series data. Journal of Remote Sensing, 2(3): 204−210.
Udo, R. K. (1970). Geographical Regions of Nigeria, Heinemann, London.