Until recently, Betula megrelica – a birch species endemic to the Caucasus – was only known to grow on two mountains in north-west Georgia. But the discovery of a new population this autumn by a team of Georgian and UK botanists has raised hopes for the future of this Endangered tree species.
Betula megrelica trees are true mountaineers of the plant world. They can be found clinging to steep slopes at altitudes between 1500-2000m, their stems often contorted and forced downwards by the weight of winter snows. Betula megrelica is one of the few tree species that can survive such conditions, yet the world’s only two known populations, found in Georgia’s Samegrelo region, are currently under threat from over-grazing and poor forestry management. After confirming the existence of these two populations in 2013, conservationists agreed that it was imperative to determine whether more populations of Betula megrelica existed, so that its full distribution could be mapped, and appropriate action taken to protect this species in the wild.
Into unknown territory
A herbarium specimen housed in the Institute of Botany in Tbilisi, Georgia’s capital, suggested that there might be another population of Betula megrelica in the Samegrelo region. Details provided with the specimen suggested it had been collected from Mount Askhi, a peak relatively close to the sites of the two known Betula megrelica populations. So in September 2015, a team made up of botanists from BGCI, Ilia State University Institute of Botany and the National Botanic Garden of Georgia, led by Paul Bartlett from Stone Lane Gardens (UK), set out to discover the whereabouts of this new, and so far elusive, population of Betula megrelica.
Tracking down a tree species that grows on the upper slopes of mountains required both heavy-duty equipment and considerable mountaineering skills from the team. An old Soviet off-road truck navigated them up steep, rocky mountain tracks, but on extreme gradients where even this vehicle struggled, the team fell to trekking across mountain terrain littered with steep drops and scree slopes.
The herbarium specimen from Ilia State University had only vague details of the exact location it had been collected from, but using Bartlett’s expertise from his previous expeditions in search of Betula megrelica, the team headed for an area with the soil type, terrain and altitude favoured by the species in other locations. On the way, they stumbled upon prints and scat of brown bear (Ursus arctos) which shares Betula megrelica’s rugged mountain habitat. The team had had a close encounter with a brown bear only a few days earlier, close to another Betula megrelica population on nearby Mount Migaria.
The hazardous expedition proved thoroughly worthwhile when, on the third day of trekking, the team found their first Betula megrelica; small and weather-stunted, but the first sign that the herbarium specimen had not sent them barking up the wrong Betula. Small individuals gave way to entire stands of mature, fruiting trees; the team had discovered a Betula megrelica stronghold that had not been documented for decades.
Cause for hope
Such a discovery has significant implications for conservation of Betula megrelica. Due to its remote location, this population is not thought to be as threatened as the other two known populations in Samegrelo, which are more frequently accessed by people for livestock grazing and logging. Furthermore, this discovery lays open the possibility that there may be more, as yet undiscovered populations of Betula megrelica in other remote and difficult-to-access locations. The existence of such populations could spell positive news for the persistence of this tree species in the wild.
However, while this new population is relatively safe from human threats for the time being, its remoteness offers no protection from long-term effects of climate change in the region, which could alter the habitat conditions that are essential for Betula megrelica to survive.
Conservation of Betula megrelica therefore cannot totally rely on just protecting the remote strongholds of the species. Something also needs to be done to protect those populations under immediate threat from human activities.
Taking action for Betula megrelica
On their return from Samegrelo, members of the expedition team held meetings with government officials in Tbilisi, Georgia’s capital. In their discussions, the team recommended that a Protected Area be established around all locations known to support populations of Betula megrelica.
Seed collected from all three populations will be stored in seed banks in Georgia and the UK, and plants will be grown and raised at Bakuriani Alpine Botanical Garden in Georgia, and at Stone Lane Gardens. These plants will form the basis for ex situ living collections, representing the full genetic variation of Betula megrelica. As well as providing an easily accessible source of wild-origin material for research, the collections could be used in the future to reinforce wild populations.
Work is also underway to establish an education programme to teach children in the Samegrelo region about their local forest areas, the plants and animals in them, the threats they face and the need to manage resources sustainably. Betula megrelica, as a species endemic to the region, will act as a flagship for this programme. As many of these children will in the future become shepherds and forestry workers, they are the people who can make the most difference to the long-term conservation of Betula megrelica and the other species which share its habitat.
This project is funded by BGCI, National Geographic Society and the Rufford Foundation.