In his book on the evolution of life, paleontologist Richard Fortey wrote about a plant that was “undoubtedly the loneliest creature in the world.” He was talking about a South African plant called Encephalartos woodii (E. woodii). E. woodii is a member of the cycad family. These plants have thick stems and large, stiff leaves that form a majestic crown. These resilient survivors have outlived the dinosaurs and several mass extinctions. They were once widespread, but today they are one of the most extinct species on the planet. The only known wild E. woodii was discovered in 1895 by botanist John Medley Wood while on a botanical expedition in South Africa’s Ngoy Forest. He looked around for plants like it but found none. Over the next few decades, botanists removed stems and branches and cultivated them in gardens.
Fearing that the last stem would be lost, the Forest Department removed it from the wild in 1916 to be kept safe in a protective enclosure in Pretoria, South Africa, thereby making it extinct in the wild. The plant has since been grown around the world. However, E. woodii faces an existential crisis. All the plants are clones of the Ngoye specimen. They are all males, and natural reproduction is impossible without a female. The story of E. woodii is one of both survival and loneliness.
My team’s research was motivated by the dilemma of the solitary plant and the possibility that a female may still be out there. Our research involved the use of remote sensing technologies and artificial intelligence to aid the search for a female in the Ngoye Forest. Cycads are the oldest living plant group today and are often referred to as “living fossils” or “dinosaur plants” because of their evolutionary history dating back to the Carboniferous period, about 300 million years ago. During the Mesozoic Era (25 million to 66 million years ago), also known as the Age of Cycads, these plants were ubiquitous, thriving in the warm, humid climate that characterized the period.
Although they resemble ferns or palms, cycads are not related to them. Cycads are gymnosperms, a group that includes conifers and ginkgo. Unlike flowering plants (angiosperms), cycads reproduce using cones. It is impossible to tell the males and females apart until they mature and form their spectacular cones. Female cones are typically broad and round, and male cones appear tall and narrow. Male cones produce pollen, which is carried to female cones by insects (mites). This ancient method of reproduction has remained largely unchanged for millions of years.
Despite their longevity, today cycads are ranked as the most endangered living organisms on Earth, with most species considered to be at risk of extinction. This is because of their slow growth and reproduction cycles, typically taking ten to 20 years to mature, and their existence is declining due to deforestation, grazing and excessive collection. This is why cycads have become symbols of botanical rarity. Their striking appearance and ancient lineage make them popular in exotic ornamental gardening and this fuels the illegal trade. Rare cycads can cost more than US$620 (£495) per cm, while some specimens sell for millions of pounds. Poaching of cycads is a threat to their survival. Among the most valuable species is E. woodii. It is protected in botanical gardens with security measures such as dangerous cages designed to deter predators.
AI in the sky
In our quest to find female E. woodii we have used innovative techniques to locate areas of the forest from a vertical vantage point. In 2022 and 2024, our drone surveys covered an area of 195 acres, or the size of 148 football fields, generating detailed maps from thousands of photographs taken by the drones. This is still only a small part of the Ngoy Forest, which spans 10,000 acres. Our AI systems enhanced the efficiency and accuracy of these searches. As E. woodii is believed to be extinct from the forest, synthetic images were used in training the AI model to improve its ability, through image recognition algorithms, to recognize cycads based on shape in different ecological contexts.
Plant species are disappearing at an alarming rate globally. Since all existing E. woodii specimens are clones, their capacity for genetic diversity in the face of environmental change and disease is limited. Notable examples include the Great Famine of Ireland in the 1840s, where the uniformity of cloned potatoes worsened the crisis, and the susceptibility of clonal Cavendish bananas to Panama disease, which threatened their production, as happened with Gros Michel bananas in the 1950s. Finding a female would mean that E. woodii is no longer on the brink of extinction and such a discovery could revive the species. A female would aid reproduction, bring genetic diversity and signal a breakthrough in conservation efforts. E. woodii is a grim reminder of the fragility of life on Earth. But our discovery of a female E. woodii shows that there is hope for even the most endangered species if we act fast enough.
Tags: World news
FIRST PUBLISHED : June 14, 2024, 12:44 IST