This year this award has been given to Professor David Richardson, deputy director of science strategy for the department of science and technology/National Research Foundation’s Centre of Excellence for Invasion Biology based at the University of Stellenbosch.
Richardson receives the award in recognition of his fundamental contributions in the rapidly emerging field of biological invasion ecology.
His work has shed new light on the dynamics of biological invasions, specifically relating to trees and shrubs, and has helped to develop robust theoretical frameworks for invasion ecology and the provision of practical guidelines for the management of invasive species.
Richardson has focused especially on the invasion ecology of tree species used in commercial forestry and agro-forestry, specifically pines.
“I’ve been researching pines for a long period,” says Richardson. “Although they are critically important in the forestry industry, they are also serious invaders in many parts of the world, causing huge headaches in terms of their environmental impact.”
The other prevalent group of plantation species, the eucalypts, as with pines, have been used all over the world in forestry, but unlike pines only a handful of eucalypt species are seriously invasive.
“Our research has focused on why these eucalypts have not been more invasive, what it is about them that is different and what could change in the future,” says Richardson.
Richardson says there are hundreds of other alien species of trees and shrubs used in agro-forestry, a term which encompasses the use of trees in various types of agriculture, be they interplanted with other agricultural crops to produce fodder for animals, used as windbreaks or to stabilise eroded ecosystems.
“Agro forestry is a huge and growing enterprise in developing countries and especially in large parts of Africa,” says Richardson.
“Unlike commercial forestry, where only a handful of tree species are used, in agro-forestry a large number of species are used. Introduction and use of these tree species, many of which have become serious invaders over large areas, have caused serious problems across the world.”
Richardson says that the most important of these invasive agro-forestry species are acacias and other woody legumes such as leucaena — a multipurpose tree native to Mexico that is used for producing fodder for livestock.
A lot of Richardson’s research has been done on exploring the biology of these invaders and thinking up innovative ways to reduce the problems these species cause as invaders.
“We can’t eradicate them because they are useful and have commercial value — in areas set aside for their cultivation,” he says.
“So we work on the basic biology and look for theoretical and conceptual frameworks to explain why some species are more successful than others and why some habitats support them better than others. By doing this we find out what makes them invasive and why and what their impact is on an ecosystem.”
Richardson defines these impacts in terms which are easy to understand for the decision makers in both governments and industry, making it easy for them to argue for expensive operations needed to clear the invader species.
Innovative research methods have revealed the main factors that determine the level of invasiveness in these species, which has led to the introduction of effective screening methods.
“We are using information from around the world — indeed, this is a global natural experiment,” says Richardson, adding that it’s impossible to do real manipulative experiments as this would be unethical in that it would entail the introduction of potentially damaging invasive species, and also impractical.