Endemic species of plant in Britain are rare and are often the product of relatively recent evolution that has occurred, in the past 10 thousand years, since the last glacial maximum. Hybridisation between species and polyploidy have caused a large range of genetic diversification in the genus Sorbus. Understanding both the evolutionary origins and breeding systems of these endemic taxa is essential to the conservation of their genetic variability and to allow their future evolution to continue, particularly in response to environmental change. It is this current state of diversification and evolution within the Sorbus genus that has lead to our interest in them here at FossilPlants. To find we had one endemic to our area (just a km away from our nursery) that was classed as Critically Endangered meant that we had to get involved in its conservation.
The Menai Strait Whitebeam (Sorbus arvonensis) is a shrub or small tree to at least 10 m tall. It is found on the top of the shore of the Menai Strait on limestone rock in open and tall woodland is endemic to this area of the Menai Strait, in North Wales. The population contains about 30 plants, and most of these are thought to be mature. It also has a highly restricted range (both extent of occurrence and area of occupancy) and is found at a single location. The main threat is from future sea level rise. Both the extent of occurrence (EOO) and the area of occupancy (AOO) are very small (<4 km2 and probably c.0.1 km2). It is found in a single location. In the future sea level rise could be a significant threat to this species, through causing erosion of the shoreline. It is therefore classified as Critically Endangered.
This joint project between FossilPlants and the National Botanic Garden of Wales (with assistance from North Wales Wildlife Trust) aims to bring into cultivation a number of individuals of Sorbus arvonensis through seed collection, produce a cultivation protocol for the species; as per the guidelines of the International Union for the Conservation of Nature (IUCN) Species Survival Commission Guidelines on the Use of Ex situ Management for Species Conservation, and thus enable the distribution of plants of this species to the wider botanic garden network securing the species in cultivation.
This project would provide background information for any future restoration or translocation initiative for S. arvonensis.
Read the Menai Strait Whitebeam Project Plan here
See The IUCN Red-List Assessment for the Menai Strait Whitebeam here
See the Menai Strait Whitebeam Global Trees Campaign profile here