Angola’s hidden flora
Botanist David Goyder describes how Kew’s inventory work and recent participation in a major international expedition to Angola is helping to address gaps in our knowledge of plant diversity in southern Africa.
Major gap in African plant collections and knowledge
Kew has had an interest in Angolan botany since at least 1862, when Joseph Hooker described the enigmatic desert plant Welwitschia mirabilis from material originating in southern Angola. Today, however, Angola presents the largest single gap in our knowledge of plant diversity in southern Africa. The outline of this large country is clearly discernible on the map below, which was generated through the GBIF portal (Global Biodiversity Information Facility) and shows georeferenced plant data available for the region – Angola lies to the north of Namibia on the Atlantic coast of Africa and is more or less square in shape. Even more apparent is the uneven distribution of records within Angola – the eastern half of the country appears as a black vertical rectangle on this map reflecting a near-complete absence of plant collections.
Civil war and remoteness deter exploration
During the colonial period, the gaps may have been due to remoteness from the major centres of population in the centre and west of the country, and perhaps also to the highly leached Kalahari sand deposits which cover much of eastern Angola. These support very little agriculture or wildlife, and the whole region is very sparsely populated. Parts of the country which were already remote and difficult to access became completely off-limits to Angolan and non-Angolan botanists alike after independence from Portugal in 1975. The 27 year civil war that followed ended in 2002, but evidence of the conflict is still all too apparent and local knowledge is vital when planning fieldwork.
The HALO Trust, which gave logistical support to the Okavango Wilderness Project and kept us safe on our most recent visit, estimates that despite years of work, approximately 25,000 land mines still need to be cleared from around Cuito Cuanavale alone, the site of the largest tank battle in Africa since the Second World War.
First inventory of Angolan plants published
In an attempt to address the lack of basic knowledge of Angolan plant diversity, eight Kew staff joined an international team to publish the first inventory of plants from the country, compiling information from existing literature and herbarium resources (Figueiredo & Smith, 2008). This work provides a baseline for future studies and lists 6,735 native species, 1,000 of which occur nowhere else. New species have been described since, both from areas thought to be well known, like the Lubango Escarpment of south-west Angola (e.g. Hind & Goyder, 2014), and from regions that until recently were inaccessible.
Botanical inventories support conservation initiatives
In 2011, the Angolan government approved a strategy to expand the network of protected areas across the country. The Ministry of the Environment (MINAMB) focussed initially on a remote and pristine valley in north-east Angola untainted by the diamond mining that has devastated other valleys in the region. Field surveys of the Carumbo area by Kew and Angolan botanists in 2011 and 2013 revealed a staggering 750 taxa, added 72 species to the national list, and highlighted 22 probable new species from the area, some of which have since been formally described (e.g. Cheek et al. 2015). Such data submitted to the Angolan government, provided evidence that helped MINAMB make the case for formal protection of this area under the Angolan protected area expansion strategy.
Other conservation initiatives have focussed on major rivers that drain south and east into the vast wetlands of Botswana’s Okavango Delta, but which originate in the central plateau of Angola. The three countries that these rivers pass through, Angola, Namibia and Botswana, are trying to ensure preservation of the environment while developing tourism and other much needed economic activity in the region. Kew conducted botanical surveys in the south east of this region in 2013, through SAREP (the Southern African Regional Environmental Programme), and in May of this year I had the chance to work with the Wild Bird Trust, who are conducting baseline surveys of the Cuito River from its source in central Angola to the inland delta of the Okavango in northern Botswana thanks to a grant from the National Geographic Society. Participation on this expedition gave access to some extremely remote regions of central and southern Angola.
All of these projects result in plant collections and high quality data from remote areas of the country and strengthen Kew’s links with Angolan institutions. We are starting to fill some of the gaps in our knowledge and our understanding of the environment. Collections from this area are the necessary first step towards an accurate inventory of the plants of eastern Angola. This in turn facilitates analysis of distributions, levels of diversity, and habitats of local or regional significance.
'Underground forests' of Africa
One habitat is of particular interest. It is a seasonally burned savanna grassland rich in geoxylic suffrutices (plants with enlarged woody structures below the ground and annually produced above-ground shoots), the 'underground forests' of Africa, whose nearest relatives are woodland or forest trees.
These grasslands support a diverse and highly specialised flora and are found only on wind-blown Kalahari sand deposits in high rainfall areas – 80% of this habitat occurs within the political boundaries of Angola. We surveyed this environment around Carumbo in north-east Angola, and again in the Cuito valley in central and southern Angola, and found many unusual range-restricted species. Recent studies on the origins of 'underground forest' species in southern Africa (Maurin et al. 2014) offer only partial explanations for this particular habitat, and probably overemphasise the role of fire at the expense of other factors that appear to limit the growth of trees in this environment. As so little of the habitat occurs outside Angola, filling gaps in the collections from this area and understanding the local ecology are vital if we are to address questions like this.
Cheek, M., Lopez Poveda, L. & Darbyshire, I. (2015). Ledermanniella lunda sp. nov. (Podostemaceae) of Lunda Norte, Angola. Kew Bulletin 70(10): 1–5. DOI 10.1007/S12225-015-9559-8. Available online
Figueiredo, E. & Smith, G. F. (2008). Plants of Angola/Plantas de Angola. Strelitzia 22. South African National Biodiversity, Institute, Pretoria.
Hind, D. J. N. & Goyder, D. J. (2014). Stomatanthes tundavalaensis (Compositae: Eupatorieae: Eupatoriinae), a new species from Huíla Province, Angola, and a synopsis of the African species of Stomatanthes. Kew Bulletin 69 (9545): 1–9. DOI 10.1007/S12225-014-9545-6. Available online
Hooker, J. D. (1862). On Welwitschia mirabilis. Gardeners Chronicle 1862: 71.
Hooker, J. D. (1863). On Welwitschia, a new genus of the Gnetaceae. Transactions of the Linnean Society of London 24: 1–48.
Maurin, O., Davies, J. T., Burrows, J. E., Daru, B. H., Yessoufou, K., Muasya, A. M., van der Bank, M. & Bond, W. J. (2014). Savanna fire and the origins of the ‘underground forests’ of Africa. New Phytologist 204: 201–214. DOI 10.1111/nph.12936. Available online
Prance, G. T. & Jongkind, C. C. H. (2015). A revision of African Lecythidaceae. Kew Bulletin 70(6): 1–68. DOI 10.1007/S12225-014-9547-4. Available online