Scarp Forest

The location of Angola in the confluence of different biomes had led to the presence of a high biodiversity in the country (Huntley 1974). It is considered one of the most important countries for birds in Africa (Dean 2000). However, knowledge of this biodiversity is limited or non-existent because of the succession of armed conflicts that lasted for over 30 years. Most information available has been collected before the independence or during recent sporadic expeditions and research projects (Ryan et al. 2004, Mills 2010).

Vegetation map of Africa: Angola has six of the seven vegetation types of Africa (Sinclair & Ryan 2010)

The Angolan Escarpment ("Scarp") Forest is one of the most interesting areas in the country in terms of biodiversity. This Forest presents affinities with the three adjacent biomes: 

• The South-West Arid 
• The Brachystegia Biome 
• The Congo-Guinean Forest 

But the Forest also acts as a barrier between these biomes (Dean 2001). Additionally its isolation and location as a natural barrier between the habitats of the Coastal Belt in the west and the High Plateau in the east provides perfect conditions for the formation of new species (Huntley 1974).

This area is particularly important for the bird communities it holds – the best documented taxa in the country – and especially for its endemics. The Angolan Scarp together with the Afromontane Forests form the Western Angola Endemic Bird Area (EBA), the country’s only centre of bird endemism. Within the EBA, the Scarp Forests hold 14 out of the 15 endemic species and five of these are restricted to this habitat. Moreover, six of these endemics are threatened (BirdLife 2011).

Western Angola Endemic Bird Area (EBA). The Angolan Escarpment Forest and the Afromontane Forest are considered the most important habitats in this EBA (BirdLife 2011)

In the north of the Angolan Scarp, due the lack of geographical barriers and isolation, the bird community is more diverse and similar with the Congo Forest and not many endemic species are present (Braun’s Bush-shrike). In the south the Forest belt becomes narrower and very dry. However in the central area the Scarp Forest presents the highest biodiversity and endemism (Mills 2010).

The unique characteristics of this Forest make it particularly important for threatened and endemic bird species. The lack of information available for this area prevented it to be considered a biodiversity hotspot (Myers et al. 2000).

Unfortunately these forests are being destroyed by the local population at an alarming pace. Slash-and-burn techniques are being used for agricultural purposes and the deforested and degraded areas are increasing. Angola endemic species are more likely to be extremely affected by these human activities, as they are restricted to small distribution ranges and had been poorly studied (Dean 2001). Most of the endemic and threatened bird species of the country are present mainly in the central Angolan Escarpment, around Gabela area (Dean 2001). The lack of knowledge of these species and the human pressure this area is suffering urges to know the effect of the human land-use in the bird’s population in order to provide strategies that will allow the conservation of this area. 

REFERENCES

* BirdLife. 2011. Endemic Bird Area factsheet: Western Angola.

* Dean, W. R. J. 2000. The Birds of Angola: an annotated checklist. BOU Checklist 18 edition.

* Dean, W. R. J. 2001. Angola. Pages 71-91 in L. D. C. Fishpool and M. I. Evans, editors. Important Birds Areas in Africa and associated islands: priority sites for conservation. Pisces Publications and BirdLife International, Newbury and Cambridge, UK.

* Huntley, B. J. 1974. Outlines of wildlife conservation in Angola. Journal of the South African Wildlife Management Association 4:157-166.

* Mills, M. 2010. Angola’s central scarp forests: patterns of bird diversity and conservation threats. Biodiversity and Conservation 19:1883-1903.

* Myers, N., R. A. Mittermeier, C. G. Mittermeier, G. A. B. da Fonseca, and J. Kent. 2000. Biodiversity hotspots for conservation priorities. Nature 403:853-858.

* Ryan, P. G., I. Sinclair, C. Cohen, M. Mills, C. Spottiswoode, and R. Cassidy. 2004. The conservation status and vocalizations of threatened birds from the scarp forest of the Western Angola Endemic Area. Bird Conservation International 14:247-260.

* Sinclair, I. and P. G. Ryan. 2010. Birds of Africa. 2nd edition. Struik Nature, Cape Town.