International Journal of
Biodiversity and Conservation

  • Abbreviation: Int. J. Biodivers. Conserv.
  • Language: English
  • ISSN: 2141-243X
  • DOI: 10.5897/IJBC
  • Start Year: 2009
  • Published Articles: 638

Full Length Research Paper

Threat of agricultural production on woody plant diversity in Tankwidi riparian buffer in the Sudanian Savanna of Ghana

Emmanuel Amoah Boakye
  • Emmanuel Amoah Boakye
  • WASCAL Graduate Research Program in Climate Change and Biodiversity, Universite Felix Houphouet Boigny, Cote d?Ivoire and WASCAL Bonn, Germany.
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Dibi N?da Hyppolite
  • Dibi N?da Hyppolite
  • WASCAL Graduate Research Program in Climate Change and Biodiversity, Universite Felix Houphouet Boigny, Cote d?Ivoire and WASCAL Bonn, Germany.
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Victor Rex Barnes
  • Victor Rex Barnes
  • Faculty of Renewable Natural Resources, Kwame Nkrumah University of Science and Technology, Ghana.
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Stefan Porembski
  • Stefan Porembski
  • Institute of Biosciences, University of Rostock, Germany.
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Michael Thiel
  • Michael Thiel
  • Department for Geography and Geology, University of Wuerzburg, Germany.
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Francois N. Kouame
  • Francois N. Kouame
  • WASCAL Graduate Research Program in Climate Change and Biodiversity, Universite Felix Houphouet Boigny, Cote d?Ivoire and WASCAL Bonn, Germany
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Daouda Kone
  • Daouda Kone
  • WASCAL Graduate Research Program in Climate Change and Biodiversity, Universite Felix Houphouet Boigny, Cote d?Ivoire and WASCAL Bonn, Germany.
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  •  Received: 13 May 2015
  •  Accepted: 30 June 2015
  •  Published: 30 July 2015

Abstract

Riparian forest buffers (RF) are integrative part of the savanna agricultural landscape. However, they are under threat of deforestation from agricultural intensification. To ascertain the impact of the deforestation, this study used remote sensing techniques and field inventorying to assess riparian woody plant diversity on farmland (FA) and forest reserve (FR) along Tankwidi rivercourse in the Sudanian savanna of Ghana. Post-classification analysis of Landsat images revealed a reduction in forest cover from 1986 (23%) to 2014 (7%) in the river basin. Ground survey of sixty randomly selected plots (500 m2 per plot) equally divided between FA and FR along the river in a 50 m buffer zone showed a reduction in the number of woody species (diameter ≥ 5 cm) from FR (40) to FA (19). Anogeissus leiocarpus and Mitragyna inermis were the most abundant species in both FR and FA. Shannon-Wiener Index for species diversity reduced from FR (2.5±0.09) to FA (1.8±0.14). Within FR, there were more species (58%) in the lower diameter class (5 to 15 cm) than the higher diameter classes (15 to 50 cm) suggesting successful regeneration. The reverse was observed in FA where the individuals in the lower diameter class were fewer (26%) than the higher diameter classes. Reduction in species density from FR (355±21) to FA (146±11) will increase the surface exposure of the riparian area in farmland to heighten risks to climate disasters such as fires and flooding. Managing the risks will not be possible unless a conscious effort is made to educate farmers on the roles of RF, replanted to enhance diversity or riparian buffer excluded from farming for vegetation recovery.
 
Key words: Riparian buffer, biodiversity, Sudanian savanna, agricultural watershed.

Abbreviation

SWI, Shannon-Wiener; SI, Simpson; RF, riparian forest; FA, farmland; FR, forest reserve; TM, thematic mapper; ETM+, enhanced thematic mapper plus; OLI, landsat operational land imager; SR, species richness.