Subsistence Agricultural Expansion Threatening Biodiversity

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Summary:

Agricultural expansion in Coastal Eastern Africa is resulting in primary vegetation loss and fragmentation. This area is home to numerous endemic species, which are extremely susceptible to habitat loss, in this case, land cover conversion for agriculture. With the current increase in population and influx of commercial agricultural prospects, the land degradation and fragmentation in the name of agricultural expansion for food will continue to threaten the region's biodiversity.

Critical Statistics:
  1. I an area that covers 291,250 sq km of the East African coast, only 29,125 sq km (less than 10%) of the natural vegetation is left undegraded (Conservation International 2007). This original vegetation is highly fragmented, resulting in small areas of viable species habitat and isolation. The need for agriculture and urban land has resulted in the conversion of around 60% of the natural forest (WWF 2006).

  2. Currently the population density is 52 people/ per sq km (Conservation International 2007), but can vary between 10 to 100 people per sq km in rural areas (WWF 2001). However, the population is projected to increase between 2.5-3.5% per year (Conservation International 2007).

  3. There are close to 2,000 endemic species residing in this area. The majority of these are plants, reptiles, and freshwater fishes, which are extremely vulnerable to changes in land cover (Conservation International 2007).

Causes:
  1. Yearly increases in population lead to increasing demands for food. The main way for farmers in this region to meet these demands is to increase the amount of cultivated land (Conservation International 2007).

  2. Burning to clear areas for agriculture is generally uncontrolled, leading to unnecessary damage to primary vegetation and species habitat (Conservation International 2007). Continuous uncontrolled fires can eventually wipe out the natural vegetation, enabling invasive species to populate the area (WWF 2006; Conservation International 2007).

  3. Commercial agricultural prospects have also expanded to this area (WWF 2001; Conservation International 2007). These plantations grow “coconut, sisal, cclove, cardamom, and cashew nuts” (Conservation International 2007).

Impacts:
  1. Fragmentation of the landscape due to agricultural expansion is a serious threat to the region's biodiversity. There are currently about 400 forest patches left in the area (WWF 2006). Habitat degradation can lead to the population decrease and potential extinction of endemic species. Land conversion to agriculture leads to vegetation patches that are too small to support viable species populations, as well as species isolation, which can result in the inability to relocate should the current area of habitat become threatened (Azeria et al. 2007).

  2. The region's poor soil necessitates shifting agriculture, where cleared land is used for a relatively short time before it is unsuitable for agriculture. This leads to a perpetuating cycle of forest clearing for subsistence agriculturalists, in a region where the demand for food is increasing (WWF 2006; Conservation International 2007).

What is Next:
  1. The development of protected areas is important to not only protect the remaining viable patches of species habitat in the region, but to also provide links or corridors between habitat patches for species travel and vegetationregrowth(WWF2006;Azeria2007)

  2. Developments with the local populace to reduce agricultural expansion through improved agricultural practices or providing an alternative income to agriculture are essential (WWF 2006).

  3. Participatory forest management with both conservation organizations and local populations is currently developing within the area in order to sustainably use forest resources (WWF 2006; Conservation International 2007).

Citations:
  1. Azeria, E.T., I. Sanmartin, S. As, A. Carlson, N.Burgess. 2007. Biogeographic Patterns of the East African Coastal Forest Vertebrate Fauna. Biodiversity and Conservation 16: 883-912.

  2. Conservation International. 2007. Coastal Forests of Eastern Africa. Www.biodiversityhotspots.org/xp/Hotspots/coastal_forests/Pages/impacts.aspx (last accessed 6 October 2009).

  3. World Wildlife Fund. 2001. Northern Zanzibar-Inhambane coastal forest mosaic. Www.worldwildlifefind.org/wildworkd/profiles/terrestrial/at/at0125_full.html (last accessed 7 October 2009).

  4. World Wildlife Fund. 2006. The Eastern Africa Coastal Forests Ecoregion: Strategic Framework for Conservation 2005-2025. Ed. K. Mungo. Http://assets.panda.org/downloads/eacfe_strategic_framework.pdf (last accessed 7 October 2009).