By Gillian Maggs-Kölling, Rosalia Iileka, Ruusa Gottlieb and Esther Uushona
The Namib is a desert landscape that stuns with its awesome scenery and fascinates with its unique geographical features. The sandy habitat, developed by superlative geological processes over millions of years, hosts a myriad of life forms that have evolved and adapted to conditions that may appear to the uninformed as harsh and inhospitable. One of the most striking examples of adaptation to arid conditions is the desert cucurbit, !nara (Acanthosicyos horridus Welw. ex Hook.f.).
The second part of the scientific name says it all – it is easily distinguished by its exceptionally spiny habit – but its rather formidable appearance belies the fact that this plant is a treasured and essential desert element. Not only does this flagship species play a vital support role to other organisms in the desert ecosystem, but is inextricably linked with desert-dwelling people to whom it offers a lifeline of sustenance, deeply entrenched within their cultural heritage. It can thus be considered both a keystone ecological and a keystone cultural species.
Description and distribution of !nara
!Nara is a leafless, thorny, melon-bearing bush that is endemic to the Namib Desert. The plants occur sporadically throughout this coastal desert from Port Nolloth in South Africa (last recorded in 1925) to Namibe in Southern Angola, with the greatest concentrations around the Kuiseb River Delta, and the most eastern distribution from around Sossusvlei. Recent explorative fieldwork has improved understanding of a more widespread occurrence in westward flowing ephemeral rivers of the northern Namib.
Plants are restricted to sand desert, often at the base of dunes, and are mostly associated with rivers ending in or flowing through the Namib, and their palaeochannels. They are absent from stony desert plains.
The plants form hummocks, which may extend over large surface areas, 1500 m2 or more, ever-increasing as the sand continues to accumulate around the plant. The spiny domes of stems may project a centimeter to one meter or higher above the hummocks. !Nara, where it occurs, is usually the dominant feature in the landscape and is not associated with other vegetation, since few other plants can survive the wind-borne sand and rainless climate. The tangled, grey- to yellow-green masses of stems enable it to be easily recognised from a distance. As the plants are leafless, a desert adaptation taken to the extreme, it is these ridged stems and paired spines of
20–30 mm long, making up almost 50% of the total surface area of the plant, which enable the plant to photosynthesise. A thick, robust tap-root system, which may extend more than 50 m below the surface,
efficiently draws moisture from deep underground. This, coupled with structural adaptations to limit evaporative water losses from the surface of the plant, enables the !nara to survive for many years without rain.
The plants are dioecious (male and female flowers on separate plants), with male flowers appearing throughout the year, and female flowers mostly during spring. Sex expression in cucurbits is controlled by environmental as well as genetic factors, and may explain discrepancies in the life-cycle events, such as flowering of northern populations, revealed during recent fieldwork.
!Nara fruit are round and melon-like, weighing mostly around 1 kg but sometimes reaching up to 2.5 kg. They are pale-green even when ripe, and spiny on the outside. The fruit has a mass of watery, orange-yellow pulp, which is sweet and aromatic, tasting like avocado or a cross between cucumber and pineapple. Toxic and potentially therapeutic compounds called cucurbitacins, which cause bitterness in the fruit, are currently under investigation in !nara. Further study of these compounds could elucidate taxonomic relationships; provide evidence to support the hypothesis of pre-selection as a husbandry practice; as well as present opportunities for novel pharmaceutical product development due to their professed anticancer properties. The large seeds are white to cream in colour with buttery kernels.
History of use
Significant data exist that intimate a long history of use. Fossilised plant roots occurring in Tsondab Sandstone suggest that !nara may have existed for as long as the Namib dunes. The earliest evidence of human use was documented through the identification of seed coat fragments from an archaeological site at Mirabib Hill shelter near Gobabeb, dated at approximately 8,000 years old. Several millennia after the initial introduction of pottery to Namib inhabitants, the appearance of wide-mouthed, soot-covered clay pots at 800-year-old
archaeological sites indicates local innovation of cooking !nara fruit.
As evidenced by special praise songs that extol its virtue, !nara has a long association with and is central to the culture of the ≠Aonin/Topnaar people who have lived along the ephemeral Kuiseb River for more than 600 years.
Products from the !nara plant
The oil produced from the seeds is bottled or mixed with other ingredients in food products or cosmetics. These products are available at the on-site Desert Hills outlet, as well as selected retailers in Namibia. International specialty cosmetic companies, such as The Body Shop, have previously expressed interest in the oil, but have been deterred by concerns regarding guaranteed supply of raw material
Future of a nascent !nara industry
Given the obvious promise of !nara, it is somewhat surprising that the plant has not been prioritised in re-levant INP programmes in Namibia. This reluctance has been ascribed to a plethora of complex and sensitive ecological, economic and social issues. During the early 2000s, a concerted effort to initiate multidisciplinary investigations into the biology and economics of this species was spearheaded by the Gobabeb Research and Training Centre and endorsed by the Topnaar Traditional Authority. The INP sector in Namibia has since matured and is gaining international credibility with the development and marketing of several successful plant derivatives, coupled with fair and effective benefit-sharing arrangements. A current resurgence of interest in the species, from a scientific as well as a development perspective, coupled with appropriate investment and a shared vision for its development, may elevate the !nara to its rightful place on the INP platform.