The Wild Cycad Conservancy
Genetic and pollination research to support cycad conservation
By John Donaldson & Vanessa Handley
OUR NEWS
Are there too many cycad species in South Africa?
By using existing genetic approaches, it is difficult to distinguish between several of the 37 Encephalartos species described from South Africa. This could mean that taxonomists have been too eager to describe new species or that the genetic methods are not refined enough to accurately resolve species.
Probably both are true, which raises important questions, for example:
- Which species or populations should be prioritised for conservation action;
- And what tools can be used to identify populations that are important for conservation?
Unravelling species relationships
In April 2024, we convened an international interdisciplinary team in the Eastern Cape. Here we kickstarted a research project which aims to develop more informative methods to unravel species relationships and support conservation planning and action. Our aim is to combine genomic information with morphological and ecological data to identify methods that can better resolve the relationship between the different cycad populations.
An ideal group for developing and testing these methods comprises the four Eastern Cape ‘blue’ cycads: Encephalartos arenarius, E. horridus, E. lehmannii, and E. trispinosus. These species are poorly differentiated in many phylogenetic studies and some populations are hard to identify based on morphology alone.
What the insects are telling us
On the flip side, past (incomplete) insect surveys revealed that these cycads have separate beetle pollinators, which would act as a barrier to gene flow between them. This supports their status as valid species.
There is also an increasing body of knowledge showing that gene flow between populations is affected by variation in the odours released by the cycads to attract pollinators. That means matching genome data to more comprehensive information on insect pollinators and cone odours can inform our understanding of how different populations are related to each other.
Above: Sampling cone odours in the Eastern Cape.
Fortunately, many populations were coning, and we managed to sample leaflets for DNA extraction from 18 populations of the four species together with beetles and cone volatiles from many of them.
Above: The team with SANParks staff after their daily exercise, hunting and finding wild cycads.
This represents the most comprehensive population-level sampling for any cycad complex in Africa.
It includes the first beetles obtained from E. arenarius in the wild, as well as the first cone volatiles collected from wild populations of several species. This is a very exciting start and we are now in the process of analysing the samples. The results will start to be published in 2025.
Special thanks go to:
the conservation authorities; the landowners who allowed us to access the plants; the funder of our two postdoctoral fellows, James Clugston who is working on the genomics and Paul Janse van Rensburg, who is studying the pollinators; and the San Diego Zoo and Wildlife Alliance who funded our fieldwork in the Eastern Cape.
Paul Janse van Rensburg and Vanessa Handley collecting samples in the Eastern Cape.
Our PROJECTS
The Wild Cycad Conservancy (or WCC) takes a three-pronged approach to cycad conservation.