Studying the oldest plants in the world
Welwitschia mirabilis are the Methuselahs of the plant kingdom, with carbon dating revealing that medium-sized plants can be as old as 1 000 years. Very little is known about these extraordinary plants, despite the fact that they are among the oldest living plants on planet Earth. This, coupled with the fact that Welwitschias occur in abundance on the Swakop Uranium Exclusive Prospecting Licence (EPL) area, prompted the company to get to know them better.
It started in 2009 with a pioneering census of the Welwitschia plants within Swakop Uranium’s EPL. Over 52 000 of the plants have been counted in the Welwitschia Flats area over the past four years. This field is now being studied with an unprecedented intensity in order to grasp what makes a Welwitschia population tick and what it requires to keep on ticking.
Swakop Uranium’s Welwitschia census, which documented the plant’s position, its relative state of health and size, its gender, and position in the landscape will be a vital addition to many other research papers that have been conducted in the past. Despite more than 300 research papers having been published on this tenacious plant, several mysteries remain – among which are “what does the root system of the Welwitschia look like, and how does it access water?” The plant census gives botanists an indication as to where the Welwitschias occur and enables them to surmise a bit more as to what the root system needs to look like for it to utilise ground or other water sources in the desert soils.
When a few Welwitschia plants were affected by the upgrading of the temporary access road in 2011, Swakop Uranium obtained a permit from the MET to excavate the plants and maximise the scientific work that could be done as a result. The Namib Ecological Restoration and Monitoring Unit (NERMU) at Gobabeb was asked to coordinate and manage the excavations of the five affected Welwitschias and help map the root system, measure soil moisture, collect samples of roots and soil, and log the soil profiles. The permit conditions required that the excavated plants be relocated, if possible, and thus the excavated plants were replanted nearby or at the Namib Botanical Gardens near Swakopmund. We are not expecting them to survive as the excavation process was focussed on mapping the root structure, not preserving it.
Removing the plants provided a unique opportunity to improve knowledge of the root system and possible source of water, and to measure a host of other biophysical characteristics, including some of the other micro organisms associated with the plant.